diff --git a/CHANGELOG.md b/CHANGELOG.md
index c725163..c51e70a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,7 +6,7 @@ Format basé sur [Keep a Changelog](https://keepachangelog.com/fr/1.1.0/),
 et [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 > **En cours de développement** : les changements à venir sont listés dans la section
-> [Unreleased](#unreleased). La dernière version livrée est **2.27.6**.
+> [Unreleased](#unreleased). La dernière version livrée est **2.27.7**.
 
 ---
 
@@ -14,6 +14,10 @@ et [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ---
 
+## [2.27.7] — 2026-09-26
+
+---
+
 ## [2.27.6] — 2026-09-26
 
 ---
@@ -34,6 +38,14 @@ et [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### Modifié
 
+- **#85 (T6a) — extraction lecture fichiers hors du monolithe `backend/main.py`.**
+  `/api/browse/{vault}`, `/api/file/{vault}/raw|download|backlinks` et
+  `GET /api/file/{vault}` (vue rendue tous formats) sont servis par le
+  nouveau `backend/routers/files_read.py` ; modèles dans `schemas.py`,
+  `_content_disposition`/`_media_max_inline_bytes` dans
+  `backend/routers/helpers.py` (partagés avec les tranches suivantes).
+  Correctif au passage : décorateur orphelin `/s/{token}` resté en T3 et
+  double-enregistrement de `/api/conflicts` supprimés.
 - **#85 (T5) — extraction du domaine `search` hors du monolithe `backend/main.py`.**
   Les 11 routes (`/api/search`, `/advanced`, `/replace`, `/tags`,
   `/tree-search`, `/vault/{vault}/paths`, `/suggest`, `/tags/suggest`,
diff --git a/README.fr.md b/README.fr.md
index 11f8310..43d073f 100644
--- a/README.fr.md
+++ b/README.fr.md
@@ -4,7 +4,7 @@
 
 **Porte d'entrée web ultra-léger pour vos vaults Obsidian** — Accédez, naviguez et recherchez dans toutes vos notes Obsidian depuis n'importe quel appareil via une interface web moderne et responsive.
 
-[![Version](https://img.shields.io/badge/Version-2.27.6-blue.svg)]()
+[![Version](https://img.shields.io/badge/Version-2.27.7-blue.svg)]()
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 [![Docker](https://img.shields.io/badge/Docker-Ready-blue.svg)](https://www.docker.com/)
 [![Python](https://img.shields.io/badge/Python-3.11+-green.svg)](https://www.python.org/)
@@ -976,8 +976,8 @@ Ce projet est sous licence **MIT** — voir le fichier [LICENSE](LICENSE) pour l
 
 ## 📝 Changelog
 
-Consultez le [CHANGELOG.md](./CHANGELOG.md) pour l'historique complet de toutes les versions (v1.0.0 → v2.27.6).
+Consultez le [CHANGELOG.md](./CHANGELOG.md) pour l'historique complet de toutes les versions (v1.0.0 → v2.27.7).
 
 ---
 
-*Projet : ObsiGate | Version : 2.27.6 | Dernière mise à jour : Septembre 2026*
+*Projet : ObsiGate | Version : 2.27.7 | Dernière mise à jour : Septembre 2026*
diff --git a/README.md b/README.md
index e2c3b36..4ee85e8 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 **Ultra-light web gateway for your Obsidian vaults** — Access, browse, and search all your Obsidian notes from any device via a modern, responsive web interface.
 
-[![Version](https://img.shields.io/badge/Version-2.27.6-blue.svg)]()
+[![Version](https://img.shields.io/badge/Version-2.27.7-blue.svg)]()
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 [![Docker](https://img.shields.io/badge/Docker-Ready-blue.svg)](https://www.docker.com/)
 [![Python](https://img.shields.io/badge/Python-3.11+-green.svg)](https://www.python.org/)
@@ -1151,8 +1151,8 @@ This project is licensed under the **MIT License** - see the [LICENSE](LICENSE)
 
 ## 📝 Changelog
 
-See [CHANGELOG.md](./CHANGELOG.md) for the complete version history (v1.0.0 → v2.27.6).
+See [CHANGELOG.md](./CHANGELOG.md) for the complete version history (v1.0.0 → v2.27.7).
 
 ---
 
-*Project: ObsiGate | Version: 2.27.6 | Last updated: September 2026*
+*Project: ObsiGate | Version: 2.27.7 | Last updated: September 2026*
diff --git a/VERSION b/VERSION
index 9b38703..28e21cc 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.27.6
+2.27.7
diff --git a/backend/main.py b/backend/main.py
index 7c366ba..699720d 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -11,7 +11,6 @@ import urllib.request
 from contextlib import asynccontextmanager
 from pathlib import Path
 from typing import Any
-from urllib.parse import quote
 
 import frontmatter
 import mistune
@@ -33,11 +32,9 @@ from backend.history import (
 )
 from backend.image_processor import preprocess_images
 from backend.indexer import (
-    _extract_tags,
     add_vault_to_index,
     build_index,
     find_file_in_index,
-    get_backlinks,
     get_conflicts,
     get_vault_data,
     handle_file_move,
@@ -64,7 +61,6 @@ from backend.schemas import (
     AppConfigResponse,
     AttachmentRescanResponse,
     AttachmentStatsResponse,
-    BacklinksResponse,
     BookmarksResponse,
     BookmarkToggleResponse,
     ConflictResolveResponse,
@@ -87,7 +83,6 @@ from backend.search import (
 from backend.semantic_search import init_semantic_index
 from backend.services.backups import get_backup_dir as service_get_backup_dir
 from backend.services.errors import ServiceError
-from backend.services.files import read_raw_file
 from backend.services.mutations import (
     batch_upload_files as service_batch_upload_files,
 )
@@ -121,7 +116,6 @@ from backend.services.mutations import (
 from backend.services.recent import humanize_mtime, list_recent
 from backend.services.sanitizer import sanitize_html
 from backend.services.vaults import (
-    browse_directory,
     list_accessible_vaults,
     list_all_files,
 )
@@ -149,64 +143,6 @@ class VaultInfo(BaseModel):
     type: str = Field(default="VAULT", description="Type of the vault mapping (VAULT or DIR)")
 
 
-class BrowseItem(BaseModel):
-    """A single entry (file or directory) returned by the browse endpoint."""
-    name: str = Field(description="File or directory name")
-    path: str = Field(description="Relative path within vault")
-    type: str = Field(description="'file' or 'directory'")
-    children_count: int | None = Field(default=None, description="Number of children (directories only)")
-    size: int | None = Field(default=None, description="File size in bytes")
-    extension: str | None = Field(default=None, description="File extension")
-
-
-class BrowseResponse(BaseModel):
-    """Paginated directory listing for a vault."""
-    vault: str
-    path: str
-    items: list[BrowseItem]
-
-
-class FileContentResponse(BaseModel):
-    """Rendered file content with metadata."""
-    vault: str = Field(description="Vault name")
-    path: str = Field(description="Relative file path within the vault")
-    title: str = Field(description="File title (from frontmatter or filename)")
-    tags: list[str] = Field(description="Extracted tags from frontmatter and inline #tags")
-    frontmatter: dict[str, Any] = Field(description="YAML frontmatter as key-value dict")
-    html: str = Field(description="Rendered HTML content")
-    raw_length: int = Field(description="Length of raw file content in characters")
-    extension: str = Field(description="File extension (e.g. .md, .txt)")
-    is_markdown: bool = Field(description="Whether the file is markdown")
-    unsupported: bool | None = Field(default=False, description="True for binary/unsupported files")
-    size_bytes: int | None = Field(default=None, description="File size in bytes (for unsupported files)")
-    is_pdf: bool | None = Field(default=None, description="True for PDF files")
-    is_image: bool | None = Field(default=None, description="True for image files")
-    is_audio: bool | None = Field(default=None, description="True for audio files (HTML5 <audio>, roadmap #109)")
-    is_video: bool | None = Field(default=None, description="True for video files (HTML5 <video>, roadmap #109)")
-    media_too_large: bool | None = Field(default=None, description="True when audio/video exceeds the inline streaming limit")
-    stream_url: str | None = Field(default=None, description="Byte-range streaming URL under /api/media (audio/video)")
-    media_mime: str | None = Field(default=None, description="MIME type for audio/video files")
-    is_csv: bool | None = Field(default=None, description="True for CSV files")
-    is_xlsx: bool | None = Field(default=None, description="True for Excel .xlsx files")
-    xlsx_sheets: list[dict[str, Any]] | None = Field(
-        default=None, description="Rendered xlsx sheets [{name, html}]"
-    )
-    is_json: bool | None = Field(default=None, description="True for JSON files")
-    is_excalidraw: bool | None = Field(default=None, description="True for Excalidraw diagram files")
-    excalidraw_data: dict[str, Any] | None = Field(default=None, description="Excalidraw diagram data (elements, appState, files)")
-    excalidraw_data_compressed: str | None = Field(default=None, description="Compressed Excalidraw data for .excalidraw.md files")
-    pdf_metadata: dict[str, Any] | None = Field(default=None, description="PDF metadata")
-    pdf_toc: list[dict[str, Any]] | None = Field(default=None, description="PDF table of contents")
-    image_mime: str | None = Field(default=None, description="MIME type for image files")
-
-
-class FileRawResponse(BaseModel):
-    """Raw text content of a file."""
-    vault: str = Field(description="Vault name")
-    path: str = Field(description="Relative file path within the vault")
-    raw: str = Field(description="Raw file content as text")
-
-
 class FileSaveResponse(BaseModel):
     """Confirmation after saving a file."""
     status: str = Field(description="Always 'ok'")
@@ -717,6 +653,7 @@ from backend.ai_routes import router as ai_router
 from backend.bookslm_routes import router as bookslm_router
 from backend.export import ExportError, export_epub, export_html, export_md_bundle
 from backend.routers.backups import router as backups_router
+from backend.routers.files_read import router as files_read_router
 from backend.routers.health import router as health_router
 from backend.routers.search import router as search_router
 from backend.routers.sharing import router as sharing_router
@@ -733,6 +670,7 @@ app.include_router(skills_router)
 app.include_router(health_router)  # ROADMAP #85 T1 — System / health
 app.include_router(search_router)  # ROADMAP #85 T5 — Search
 app.include_router(backups_router)  # ROADMAP #85 T4 — Backups
+app.include_router(files_read_router)  # ROADMAP #85 T6a — Files read
 app.include_router(webhooks_router)  # ROADMAP #85 T2 — Webhooks
 app.include_router(sharing_router)  # ROADMAP #85 T3 — Sharing
 
@@ -784,44 +722,11 @@ async def api_docs_landing():
 
 
 # ---------------------------------------------------------------------------
-# Path safety helper
+# Path safety helper : voir backend.routers.helpers (#85 T6a)
 # ---------------------------------------------------------------------------
 
-def _content_disposition(disposition: str, filename: str) -> str:
-    """Build a header-safe Content-Disposition value.
-
-    HTTP header values must be ASCII. Unicode filenames are sent per
-    RFC 5987 via ``filename*`` (percent-encoded UTF-8) with a pure-ASCII
-    ``filename`` fallback. This avoids a UnicodeDecodeError / HTTP 500 when
-    the filename contains accented characters (e.g. 'Bière blonde…pdf').
-    """
-    from urllib.parse import quote
-    ascii_name = "".join(c for c in filename if c.isascii() and (c.isalnum() or c in " _-.")).strip() or "file"
-    ext = Path(filename).suffix
-    if ext and not Path(ascii_name).suffix:
-        ascii_name = ascii_name + ext
-    return f"{disposition}; filename=\"{ascii_name}\"; filename*=UTF-8''{quote(filename)}"
-
-
-def _media_max_inline_bytes() -> int:
-    """Maximum size (bytes) for inline audio/video playback (roadmap #109-A3).
-
-    Configurable via ``OBSIGATE_MEDIA_MAX_INLINE_MB`` (default 500 MB). Files
-    above the limit are not streamed in the viewer (the UI falls back to the
-    download button), which keeps a single uvicorn worker from being pinned by
-    multi-gigabyte media. Invalid or non-positive values fall back to default.
-    """
-    default_mb = 500
-    raw = os.environ.get("OBSIGATE_MEDIA_MAX_INLINE_MB", "").strip()
-    if not raw:
-        return default_mb * 1024 * 1024
-    try:
-        mb = float(raw)
-    except ValueError:
-        return default_mb * 1024 * 1024
-    if mb <= 0:
-        return default_mb * 1024 * 1024
-    return int(mb * 1024 * 1024)
+from backend.routers.helpers import content_disposition as _content_disposition
+from backend.routers.helpers import media_max_inline_bytes as _media_max_inline_bytes
 
 
 def _resolve_safe_path(vault_root: Path, relative_path: str | None) -> Path:
@@ -1199,97 +1104,9 @@ async def api_delete_saved_search(search_id: str, current_user=Depends(require_a
     return {"status": "deleted"}
 
 
-@app.get("/api/browse/{vault_name}", response_model=BrowseResponse)
-async def api_browse(vault_name: str, path: str = "", current_user=Depends(require_auth)):
-    """Browse directories and files in a vault at a given path level.
-
-    Returns sorted entries (directories first, then files) with metadata.
-    Hidden files/directories (starting with ``"."`` ) are excluded.
-
-    Args:
-        vault_name: Name of the vault to browse.
-        path: Relative directory path within the vault (empty = root).
-
-    Returns:
-        ``BrowseResponse`` with vault name, path, and item list.
-    """
-    if not check_vault_access(vault_name, current_user):
-        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
-    return browse_directory(vault_name, path)
-
-
-# Map file extensions to highlight.js language hints
-EXT_TO_LANG = {
-    ".py": "python", ".js": "javascript", ".ts": "typescript",
-    ".jsx": "jsx", ".tsx": "tsx", ".sh": "bash", ".bash": "bash",
-    ".zsh": "bash", ".fish": "fish", ".bat": "batch", ".cmd": "batch",
-    ".ps1": "powershell", ".json": "json", ".yaml": "yaml", ".yml": "yaml",
-    ".toml": "toml", ".xml": "xml", ".csv": "plaintext",
-    ".cfg": "ini", ".ini": "ini", ".conf": "ini", ".env": "bash",
-    ".html": "html", ".css": "css", ".scss": "scss", ".less": "less",
-    ".java": "java", ".c": "c", ".cpp": "cpp", ".h": "c", ".hpp": "cpp",
-    ".cs": "csharp", ".go": "go", ".rs": "rust", ".rb": "ruby",
-    ".php": "php", ".sql": "sql", ".r": "r", ".swift": "swift",
-    ".kt": "kotlin", ".txt": "plaintext", ".log": "plaintext",
-    ".lua": "lua", ".pl": "perl", ".pm": "perl", ".ex": "elixir", ".exs": "elixir",
-    ".dart": "dart", ".tf": "haskell", ".gradle": "groovy", ".groovy": "groovy",
-    ".graphql": "graphql", ".gql": "graphql", ".prisma": "sql", ".proto": "c",
-    ".vb": "basic", ".asm": "x86asm", ".s": "armasm",
-    ".vue": "xml", ".svelte": "xml", ".astro": "xml",
-    ".properties": "ini", ".service": "ini", ".hosts": "ini",
-    ".ksh": "bash", ".dockerfile": "dockerfile",
-    ".makefile": "makefile", ".cmake": "cmake",
-}
-
-
-@app.get("/api/file/{vault_name}/raw", response_model=FileRawResponse)
-async def api_file_raw(vault_name: str, path: str = Query(..., description="Relative path to file"), current_user=Depends(require_auth)):
-    """Return raw file content as plain text.
-
-    Args:
-        vault_name: Name of the vault.
-        path: Relative file path within the vault.
-
-    Returns:
-        ``FileRawResponse`` with vault, path, and raw text content.
-    """
-    if not check_vault_access(vault_name, current_user):
-        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
-    return read_raw_file(vault_name, path)
-
-
-@app.get("/api/file/{vault_name}/download", response_class=FileResponse)
-async def api_file_download(vault_name: str, path: str = Query(..., description="Relative path to file"), current_user=Depends(require_auth)):
-    """Download a file as an attachment.
-
-    Args:
-        vault_name: Name of the vault.
-        path: Relative file path within the vault.
-
-    Returns:
-        ``FileResponse`` with ``application/octet-stream`` content-type.
-    """
-    if not check_vault_access(vault_name, current_user):
-        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
-    vault_data = get_vault_data(vault_name)
-    if not vault_data:
-        raise HTTPException(status_code=404, detail=f"Vault '{vault_name}' not found")
-
-    vault_root = Path(vault_data["path"])
-    file_path = _resolve_safe_path(vault_root, path)
-
-    if not file_path.exists() or not file_path.is_file():
-        raise HTTPException(status_code=404, detail=f"File not found: {path}")
-
-    # Record history
-    record_open(current_user.get("username"), vault_name, path)
-
-    return FileResponse(
-        path=str(file_path),
-        filename=file_path.name,
-        media_type="application/octet-stream",
-    )
-
+# ---------------------------------------------------------------------------
+# File browse & read endpoints : voir backend.routers.files_read (#85 T6a)
+# ---------------------------------------------------------------------------
 
 @app.get(
     "/api/file/{vault_name}/pdf",
@@ -1906,389 +1723,7 @@ def _get_backup_dir(vault_name: str, relative_path: str) -> Path:
 # File-level backup endpoints : voir backend.routers.backups (#85 T4)
 # ---------------------------------------------------------------------------
 
-@app.get("/api/file/{vault_name}/backlinks", response_model=BacklinksResponse)
-async def api_file_backlinks(
-    vault_name: str,
-    path: str = Query(..., description="Relative path to file"),
-    current_user=Depends(require_auth),
-):
-    """Get backlinks (files linking to this file via wikilinks).
-
-    Returns a list of files that contain `[[wikilinks]]` pointing
-    to the requested file, across all accessible vaults.
-
-    Args:
-        vault_name: Name of the vault containing the target file.
-        path: Relative path of the target file within the vault.
-
-    Returns:
-        ``{"vault": str, "path": str, "backlinks": [...]}``
-    """
-    if not check_vault_access(vault_name, current_user):
-        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
-    vault_data = get_vault_data(vault_name)
-    if not vault_data:
-        raise HTTPException(status_code=404, detail=f"Vault '{vault_name}' not found")
-
-    user_vaults = current_user.get("_token_vaults") or current_user.get("vaults", [])
-    backlinks = get_backlinks(vault_name, path)
-
-    # Filter by user-accessible vaults
-    if "*" not in user_vaults:
-        backlinks = [b for b in backlinks if b["vault"] in user_vaults]
-
-    return {
-        "vault": vault_name,
-        "path": path,
-        "backlinks": backlinks,
-        "total": len(backlinks),
-    }
-
-
-@app.get("/api/file/{vault_name}", response_model=FileContentResponse)
-async def api_file(vault_name: str, path: str = Query(..., description="Relative path to file"), current_user=Depends(require_auth)):
-    """Return rendered HTML and metadata for a file.
-
-    Markdown files are parsed for frontmatter, rendered with wikilink
-    support, and returned with extracted tags. Other supported file
-    types are syntax-highlighted as code blocks.
-
-    Args:
-        vault_name: Name of the vault.
-        path: Relative file path within the vault.
-
-    Returns:
-        ``FileContentResponse`` with HTML, metadata, and tags.
-    """
-    if not check_vault_access(vault_name, current_user):
-        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
-    vault_data = get_vault_data(vault_name)
-    if not vault_data:
-        raise HTTPException(status_code=404, detail=f"Vault '{vault_name}' not found")
-
-    vault_root = Path(vault_data["path"])
-    file_path = _resolve_safe_path(vault_root, path)
-
-    if not file_path.exists() or not file_path.is_file():
-        raise HTTPException(status_code=404, detail=f"File not found: {path}")
-
-    # Record history
-    record_open(current_user.get("username"), vault_name, path, title=file_path.name)
-
-    ext = file_path.suffix.lower()
-
-    # === PDF: special handling before read_text (binary file) ===
-    if ext == ".pdf":
-        try:
-            from backend.pdf_reader import extract_pdf_metadata, extract_pdf_text, extract_pdf_toc
-            pdf_text = extract_pdf_text(file_path, max_chars=100000)
-            pdf_meta = extract_pdf_metadata(file_path)
-            pdf_toc = extract_pdf_toc(file_path)
-            size = file_path.stat().st_size
-            return {
-                "vault": vault_name,
-                "path": path,
-                "title": pdf_meta.get("title") or file_path.name,
-                "tags": [],
-                "frontmatter": {},
-                "html": f"<div class='pdf-viewer'><p>PDF — {pdf_meta.get('pages', '?')} pages</p><pre>{pdf_text[:5000]}</pre></div>",
-                "raw_length": size,
-                "extension": ext,
-                "is_markdown": False,
-                "is_pdf": True,
-                "unsupported": False,
-                "pdf_metadata": pdf_meta,
-                "pdf_toc": pdf_toc,
-                "size_bytes": size,
-            }
-        except Exception as e:
-            logger.error(f"PDF read error for {path}: {e}")
-            raise HTTPException(status_code=500, detail=f"Error reading PDF: {e!s}")
-
-    # === Excel .xlsx: render sheets as HTML tables (binary, before read_text) ===
-    if ext == ".xlsx":
-        try:
-            from backend.xlsx_reader import render_sheets
-
-            sheets = render_sheets(file_path)
-            size = file_path.stat().st_size
-            return {
-                "vault": vault_name,
-                "path": path,
-                "title": file_path.name,
-                "tags": [],
-                "frontmatter": {},
-                "html": sheets[0]["html"] if sheets else "",
-                "raw_length": size,
-                "extension": ext,
-                "is_markdown": False,
-                "is_xlsx": True,
-                "xlsx_sheets": sheets,
-                "unsupported": False,
-                "size_bytes": size,
-            }
-        except Exception as e:
-            logger.error(f"XLSX read error for {path}: {e}")
-            raise HTTPException(status_code=500, detail=f"Error reading XLSX: {e!s}")
-
-    # === Images: return as viewable image ===
-    if is_image(ext):
-        size = file_path.stat().st_size
-        mime = media_mime_type(str(file_path))
-        # #108-B1 — the raw endpoint returns JSON (FileRawResponse), so the
-        # standalone <img> must point to /api/image, which serves the bytes
-        # with the right MIME type. Paths are URL-encoded (accents, spaces).
-        img_url = f"/api/image/{quote(vault_name, safe='')}?path={quote(path, safe='')}"
-        html = (
-            f'<div class="image-viewer">'
-            f'<img src="{img_url}" '
-            f'alt="{html_mod.escape(file_path.name, quote=True)}" '
-            f'style="max-width:100%;max-height:80vh;object-fit:contain" />'
-            f'</div>'
-        )
-        return {
-            "vault": vault_name,
-            "path": path,
-            "title": file_path.name,
-            "tags": [],
-            "frontmatter": {},
-            "html": html,
-            "raw_length": size,
-            "extension": ext,
-            "is_markdown": False,
-            "is_image": True,
-            "image_mime": mime,
-            "size_bytes": size,
-        }
-
-    # === Audio / Video: HTML5 players streamed from /api/media (roadmap #109) ===
-    if is_audio(ext) or is_video(ext):
-        size = file_path.stat().st_size
-        mime = media_mime_type(str(file_path))
-        media_kind = "audio" if is_audio(ext) else "video"
-
-        # #109-A3 — beyond the inline limit the viewer falls back to download
-        # (a single uvicorn worker must not be pinned by multi-GB media).
-        if size > _media_max_inline_bytes():
-            return {
-                "vault": vault_name,
-                "path": path,
-                "title": file_path.name,
-                "tags": [],
-                "frontmatter": {},
-                "html": "",
-                "raw_length": size,
-                "extension": ext,
-                "is_markdown": False,
-                "unsupported": True,
-                "media_too_large": True,
-                "size_bytes": size,
-            }
-
-        # #109-A2 — byte-range endpoint: enables scrub and is required by Safari.
-        stream_url = f"/api/media/{quote(vault_name, safe='')}?path={quote(path, safe='')}"
-        if media_kind == "audio":
-            html = (
-                f'<div class="audio-viewer">'
-                f'<audio controls preload="metadata" src="{stream_url}"></audio>'
-                f'</div>'
-            )
-        else:
-            html = (
-                f'<div class="video-viewer">'
-                f'<video controls playsinline preload="metadata" src="{stream_url}"></video>'
-                f'</div>'
-            )
-        return {
-            "vault": vault_name,
-            "path": path,
-            "title": file_path.name,
-            "tags": [],
-            "frontmatter": {},
-            "html": html,
-            "raw_length": size,
-            "extension": ext,
-            "is_markdown": False,
-            "is_audio": media_kind == "audio",
-            "is_video": media_kind == "video",
-            "media_mime": mime,
-            "stream_url": stream_url,
-            "size_bytes": size,
-        }
-
-    try:
-        raw = file_path.read_text(encoding="utf-8", errors="replace")
-    except PermissionError as e:
-        logger.error(f"Permission denied reading file {path}: {e}")
-        raise HTTPException(status_code=403, detail=f"Permission denied: cannot read file {path}")
-    except UnicodeDecodeError:
-        # Binary / unsupported file — return structured info with download option
-        size = file_path.stat().st_size
-        return {
-            "vault": vault_name,
-            "path": path,
-            "title": file_path.name,
-            "tags": [],
-            "frontmatter": {},
-            "html": "",
-            "raw_length": size,
-            "extension": ext,
-            "is_markdown": False,
-            "unsupported": True,
-            "size_bytes": size,
-        }
-    except Exception as e:
-        logger.error(f"Unexpected error reading file {path}: {e}")
-        raise HTTPException(status_code=500, detail=f"Error reading file: {e!s}")
-
-    # === CSV: render as HTML table ===
-    if ext == ".csv":
-        import csv
-        import io as csv_io
-        reader = csv.reader(csv_io.StringIO(raw))
-        rows = list(reader)
-        if not rows:
-            html = "<p><em>Fichier CSV vide</em></p>"
-        else:
-            headers = rows[0]
-            data_rows = rows[1:]
-            html = '<div class="csv-table-wrapper"><table class="csv-table"><thead><tr>'
-            for h in headers:
-                html += f"<th>{h}</th>"
-            html += "</tr></thead><tbody>"
-            for row in data_rows:
-                html += "<tr>"
-                for cell in row:
-                    html += f"<td>{cell}</td>"
-                html += "</tr>"
-            html += "</tbody></table></div>"
-        return {
-            "vault": vault_name, "path": path,
-            "title": file_path.name, "tags": [], "frontmatter": {},
-            "html": html, "raw_length": len(raw), "extension": ext,
-            "is_markdown": False, "is_csv": True,
-        }
-
-    # === JSON: syntax-highlighted display ===
-    if ext == ".json":
-        import json as json_mod
-        try:
-            parsed = json_mod.loads(raw)
-            formatted = json_mod.dumps(parsed, indent=2, ensure_ascii=False)
-        except json_mod.JSONDecodeError:
-            formatted = raw
-        html = f"<pre class='json-viewer'><code>{html_mod.escape(formatted)}</code></pre>"
-        return {
-            "vault": vault_name, "path": path,
-            "title": file_path.name, "tags": [], "frontmatter": {},
-            "html": html, "raw_length": len(raw), "extension": ext,
-            "is_markdown": False, "is_json": True,
-        }
-
-    # === Excalidraw .excalidraw.md (Obsidian plugin format) ===
-    if path.lower().endswith(".excalidraw.md"):
-        import re as re_mod
-        raw_lower = file_path.read_text(encoding="utf-8", errors="replace")
-        # Check for excalidraw-plugin in frontmatter or body
-        if "excalidraw-plugin:" in raw_lower:
-            # Extract compressed JSON block
-            match = re_mod.search(r'```compressed-json\n(.*?)\n```', raw_lower, re_mod.DOTALL)
-            if match:
-                compressed = match.group(1).strip()
-                return {
-                    "vault": vault_name, "path": path,
-                    "title": file_path.name.replace(".excalidraw.md", ""),
-                    "tags": [], "frontmatter": {},
-                    "html": "", "raw_length": len(raw_lower),
-                    "extension": ".excalidraw.md",
-                    "is_markdown": False,
-                    "is_excalidraw": True,
-                    "excalidraw_data_compressed": compressed,
-                }
-        # Fallback: treat as regular markdown
-        raw = raw_lower
-    if ext == ".excalidraw":
-        import json as json_mod
-        try:
-            parsed = json_mod.loads(raw)
-        except json_mod.JSONDecodeError:
-            parsed = None
-        if parsed and parsed.get("type") == "excalidraw":
-            return {
-                "vault": vault_name,
-                "path": path,
-                "title": parsed.get("appState", {}).get("name") or file_path.name,
-                "tags": [],
-                "frontmatter": {},
-                "html": "",
-                "raw_length": len(raw),
-                "extension": ext,
-                "is_markdown": False,
-                "is_excalidraw": True,
-                "excalidraw_data": {
-                    "elements": parsed.get("elements", []),
-                    "appState": parsed.get("appState", {}),
-                    "files": parsed.get("files", {}),
-                },
-            }
-        else:
-            # Not a valid Excalidraw file — fall through to text viewer
-            pass
-
-    # === Plain text / other readable files ===
-    TEXT_EXTENSIONS = {".txt", ".log", ".yml", ".yaml", ".toml", ".ini", ".cfg",
-                       ".sh", ".bash", ".py", ".js", ".ts", ".html", ".css",
-                       ".xml", ".rst", ".tex", ".sql", ".conf", ".env"}
-    if ext in TEXT_EXTENSIONS or ext == ".md":
-        pass  # handled below or by markdown section
-
-    if ext == ".md":
-        post = parse_markdown_file(raw)
-
-        # Extract metadata using shared indexer logic
-        tags = _extract_tags(post)
-
-        title = post.metadata.get("title", file_path.stem.replace("-", " ").replace("_", " "))
-        html_content = _render_markdown(post.content, vault_name, file_path)
-
-        return {
-            "vault": vault_name,
-            "path": path,
-            "title": str(title),
-            "tags": tags,
-            "frontmatter": dict(post.metadata) if post.metadata else {},
-            "html": html_content,
-            "raw_length": len(raw),
-            "extension": ext,
-            "is_markdown": True,
-        }
-    else:
-        # Non-markdown: wrap in syntax-highlighted code block
-        lang = EXT_TO_LANG.get(ext, "")
-        if not lang:
-            # Fichiers sans extension usuels (Dockerfile, Makefile, etc.)
-            NAME_TO_LANG = {
-                "dockerfile": "dockerfile", "makefile": "makefile",
-                "cmakelists.txt": "cmake", "jenkinsfile": "groovy",
-                "vagrantfile": "ruby", "rakefile": "ruby", "gemfile": "ruby",
-                "procfile": "plaintext", "bashrc": "bash", "bash_profile": "bash",
-                "zshrc": "bash", "profile": "bash", "gitignore": "plaintext",
-            }
-            lang = NAME_TO_LANG.get(file_path.name.lower(), "plaintext")
-        escaped = html_mod.escape(raw)
-        html_content = f'<pre><code class="language-{lang}">{escaped}</code></pre>'
-
-        return {
-            "vault": vault_name,
-            "path": path,
-            "title": file_path.name,
-            "tags": [],
-            "frontmatter": {},
-            "html": html_content,
-            "raw_length": len(raw),
-            "extension": ext,
-            "is_markdown": False,
-        }
+# File backlinks + view endpoints : voir backend.routers.files_read (#85 T6a)
 
 
 def _stream_file_with_range(file_path: Path, request: Request, media_type: str):
@@ -3379,9 +2814,7 @@ async def api_dashboard(current_user=Depends(require_auth)):
 # Share (public document) endpoints : voir backend.routers.sharing (#85 T3)
 # ---------------------------------------------------------------------------
 
-@app.get("/s/{token}", response_class=HTMLResponse)
-# ---------------------------------------------------------------------------
-# Syncthing conflict endpoints
+
 # ---------------------------------------------------------------------------
 # Syncthing conflict endpoints
 # ---------------------------------------------------------------------------
diff --git a/backend/routers/files_read.py b/backend/routers/files_read.py
new file mode 100644
index 0000000..6996cef
--- /dev/null
+++ b/backend/routers/files_read.py
@@ -0,0 +1,525 @@
+"""File browsing & reading endpoints (ROADMAP #85, tranche 6a).
+
+Handlers déplacés depuis :mod:`backend.main` sans changement de
+comportement : mêmes chemins (``/api/browse/*``, ``/api/file/*`` en
+lecture), mêmes modèles de réponse (déménagés dans
+:mod:`backend.schemas`), mêmes dépendances d'authentification.
+
+Adaptations strictement équivalentes :
+- ``_resolve_safe_path`` → :mod:`backend.services.paths` (pass-through).
+- ``_render_markdown`` reste dans ``main`` (import différé, extraction
+  prévue dans une tranche ultérieure).
+- ``_content_disposition`` / ``_media_max_inline_bytes`` / ``EXT_TO_LANG``
+  ont déménagé : helpers partagés dans :mod:`backend.routers.helpers`
+  (``EXT_TO_LANG`` n'était utilisé que par la vue fichier).
+"""
+
+import html as html_mod
+import logging
+from pathlib import Path
+from urllib.parse import quote
+
+from fastapi import APIRouter, Depends, HTTPException, Query
+from fastapi.responses import FileResponse
+
+from backend.auth.middleware import check_vault_access, require_auth
+from backend.history import record_open
+from backend.indexer import (
+    _extract_tags,
+    get_backlinks,
+    get_vault_data,
+    parse_markdown_file,
+)
+from backend.media_types import is_audio, is_image, is_video, media_mime_type
+from backend.routers.helpers import media_max_inline_bytes
+from backend.schemas import (
+    BacklinksResponse,
+    BrowseResponse,
+    FileContentResponse,
+    FileRawResponse,
+)
+from backend.services.files import read_raw_file
+from backend.services.paths import resolve_safe_path
+from backend.services.vaults import browse_directory
+
+logger = logging.getLogger("obsigate")
+
+# Map file extensions to highlight.js language hints
+EXT_TO_LANG = {
+    ".py": "python", ".js": "javascript", ".ts": "typescript",
+    ".jsx": "jsx", ".tsx": "tsx", ".sh": "bash", ".bash": "bash",
+    ".zsh": "bash", ".fish": "fish", ".bat": "batch", ".cmd": "batch",
+    ".ps1": "powershell", ".json": "json", ".yaml": "yaml", ".yml": "yaml",
+    ".toml": "toml", ".xml": "xml", ".csv": "plaintext",
+    ".cfg": "ini", ".ini": "ini", ".conf": "ini", ".env": "bash",
+    ".html": "html", ".css": "css", ".scss": "scss", ".less": "less",
+    ".java": "java", ".c": "c", ".cpp": "cpp", ".h": "c", ".hpp": "cpp",
+    ".cs": "csharp", ".go": "go", ".rs": "rust", ".rb": "ruby",
+    ".php": "php", ".sql": "sql", ".r": "r", ".swift": "swift",
+    ".kt": "kotlin", ".txt": "plaintext", ".log": "plaintext",
+    ".lua": "lua", ".pl": "perl", ".pm": "perl", ".ex": "elixir", ".exs": "elixir",
+    ".dart": "dart", ".tf": "haskell", ".gradle": "groovy", ".groovy": "groovy",
+    ".graphql": "graphql", ".gql": "graphql", ".prisma": "sql", ".proto": "c",
+    ".vb": "basic", ".asm": "x86asm", ".s": "armasm",
+    ".vue": "xml", ".svelte": "xml", ".astro": "xml",
+    ".properties": "ini", ".service": "ini", ".hosts": "ini",
+    ".ksh": "bash", ".dockerfile": "dockerfile",
+    ".makefile": "makefile", ".cmake": "cmake",
+}
+
+router = APIRouter(tags=["files"])
+
+
+@router.get("/api/browse/{vault_name}", response_model=BrowseResponse)
+async def api_browse(vault_name: str, path: str = "", current_user=Depends(require_auth)):
+    """Browse directories and files in a vault at a given path level.
+
+    Returns sorted entries (directories first, then files) with metadata.
+    Hidden files/directories (starting with ``"."`` ) are excluded.
+
+    Args:
+        vault_name: Name of the vault to browse.
+        path: Relative directory path within the vault (empty = root).
+
+    Returns:
+        ``BrowseResponse`` with vault name, path, and item list.
+    """
+    if not check_vault_access(vault_name, current_user):
+        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
+    return browse_directory(vault_name, path)
+
+
+@router.get("/api/file/{vault_name}/raw", response_model=FileRawResponse)
+async def api_file_raw(vault_name: str, path: str = Query(..., description="Relative path to file"), current_user=Depends(require_auth)):
+    """Return raw file content as plain text.
+
+    Args:
+        vault_name: Name of the vault.
+        path: Relative file path within the vault.
+
+    Returns:
+        ``FileRawResponse`` with vault, path, and raw text content.
+    """
+    if not check_vault_access(vault_name, current_user):
+        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
+    return read_raw_file(vault_name, path)
+
+
+@router.get("/api/file/{vault_name}/download", response_class=FileResponse)
+async def api_file_download(vault_name: str, path: str = Query(..., description="Relative path to file"), current_user=Depends(require_auth)):
+    """Download a file as an attachment.
+
+    Args:
+        vault_name: Name of the vault.
+        path: Relative file path within the vault.
+
+    Returns:
+        ``FileResponse`` with ``application/octet-stream`` content-type.
+    """
+    if not check_vault_access(vault_name, current_user):
+        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
+    vault_data = get_vault_data(vault_name)
+    if not vault_data:
+        raise HTTPException(status_code=404, detail=f"Vault '{vault_name}' not found")
+
+    vault_root = Path(vault_data["path"])
+    file_path = resolve_safe_path(vault_root, path)
+
+    if not file_path.exists() or not file_path.is_file():
+        raise HTTPException(status_code=404, detail=f"File not found: {path}")
+
+    # Record history
+    record_open(current_user.get("username"), vault_name, path)
+
+    return FileResponse(
+        path=str(file_path),
+        filename=file_path.name,
+        media_type="application/octet-stream",
+    )
+
+
+@router.get("/api/file/{vault_name}/backlinks", response_model=BacklinksResponse)
+async def api_file_backlinks(
+    vault_name: str,
+    path: str = Query(..., description="Relative path to file"),
+    current_user=Depends(require_auth),
+):
+    """Get backlinks (files linking to this file via wikilinks).
+
+    Returns a list of files that contain `[[wikilinks]]` pointing
+    to the requested file, across all accessible vaults.
+
+    Args:
+        vault_name: Name of the vault containing the target file.
+        path: Relative path of the target file within the vault.
+
+    Returns:
+        ``{"vault": str, "path": str, "backlinks": [...]}``
+    """
+    if not check_vault_access(vault_name, current_user):
+        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
+    vault_data = get_vault_data(vault_name)
+    if not vault_data:
+        raise HTTPException(status_code=404, detail=f"Vault '{vault_name}' not found")
+
+    user_vaults = current_user.get("_token_vaults") or current_user.get("vaults", [])
+    backlinks = get_backlinks(vault_name, path)
+
+    # Filter by user-accessible vaults
+    if "*" not in user_vaults:
+        backlinks = [b for b in backlinks if b["vault"] in user_vaults]
+
+    return {
+        "vault": vault_name,
+        "path": path,
+        "backlinks": backlinks,
+        "total": len(backlinks),
+    }
+
+
+@router.get("/api/file/{vault_name}", response_model=FileContentResponse)
+async def api_file(vault_name: str, path: str = Query(..., description="Relative path to file"), current_user=Depends(require_auth)):
+    """Return rendered HTML and metadata for a file.
+
+    Markdown files are parsed for frontmatter, rendered with wikilink
+    support, and returned with extracted tags. Other supported file
+    types are syntax-highlighted as code blocks.
+
+    Args:
+        vault_name: Name of the vault.
+        path: Relative file path within the vault.
+
+    Returns:
+        ``FileContentResponse`` with HTML, metadata, and tags.
+    """
+    from backend.main import _render_markdown  # différé : évite l'import circulaire (#85)
+
+    if not check_vault_access(vault_name, current_user):
+        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
+    vault_data = get_vault_data(vault_name)
+    if not vault_data:
+        raise HTTPException(status_code=404, detail=f"Vault '{vault_name}' not found")
+
+    vault_root = Path(vault_data["path"])
+    file_path = resolve_safe_path(vault_root, path)
+
+    if not file_path.exists() or not file_path.is_file():
+        raise HTTPException(status_code=404, detail=f"File not found: {path}")
+
+    # Record history
+    record_open(current_user.get("username"), vault_name, path, title=file_path.name)
+
+    ext = file_path.suffix.lower()
+
+    # === PDF: special handling before read_text (binary file) ===
+    if ext == ".pdf":
+        try:
+            from backend.pdf_reader import extract_pdf_metadata, extract_pdf_text, extract_pdf_toc
+            pdf_text = extract_pdf_text(file_path, max_chars=100000)
+            pdf_meta = extract_pdf_metadata(file_path)
+            pdf_toc = extract_pdf_toc(file_path)
+            size = file_path.stat().st_size
+            return {
+                "vault": vault_name,
+                "path": path,
+                "title": pdf_meta.get("title") or file_path.name,
+                "tags": [],
+                "frontmatter": {},
+                "html": f"<div class='pdf-viewer'><p>PDF — {pdf_meta.get('pages', '?')} pages</p><pre>{pdf_text[:5000]}</pre></div>",
+                "raw_length": size,
+                "extension": ext,
+                "is_markdown": False,
+                "is_pdf": True,
+                "unsupported": False,
+                "pdf_metadata": pdf_meta,
+                "pdf_toc": pdf_toc,
+                "size_bytes": size,
+            }
+        except Exception as e:
+            logger.error(f"PDF read error for {path}: {e}")
+            raise HTTPException(status_code=500, detail=f"Error reading PDF: {e!s}")
+
+    # === Excel .xlsx: render sheets as HTML tables (binary, before read_text) ===
+    if ext == ".xlsx":
+        try:
+            from backend.xlsx_reader import render_sheets
+
+            sheets = render_sheets(file_path)
+            size = file_path.stat().st_size
+            return {
+                "vault": vault_name,
+                "path": path,
+                "title": file_path.name,
+                "tags": [],
+                "frontmatter": {},
+                "html": sheets[0]["html"] if sheets else "",
+                "raw_length": size,
+                "extension": ext,
+                "is_markdown": False,
+                "is_xlsx": True,
+                "xlsx_sheets": sheets,
+                "unsupported": False,
+                "size_bytes": size,
+            }
+        except Exception as e:
+            logger.error(f"XLSX read error for {path}: {e}")
+            raise HTTPException(status_code=500, detail=f"Error reading XLSX: {e!s}")
+
+    # === Images: return as viewable image ===
+    if is_image(ext):
+        size = file_path.stat().st_size
+        mime = media_mime_type(str(file_path))
+        # #108-B1 — the raw endpoint returns JSON (FileRawResponse), so the
+        # standalone <img> must point to /api/image, which serves the bytes
+        # with the right MIME type. Paths are URL-encoded (accents, spaces).
+        img_url = f"/api/image/{quote(vault_name, safe='')}?path={quote(path, safe='')}"
+        html = (
+            f'<div class="image-viewer">'
+            f'<img src="{img_url}" '
+            f'alt="{html_mod.escape(file_path.name, quote=True)}" '
+            f'style="max-width:100%;max-height:80vh;object-fit:contain" />'
+            f'</div>'
+        )
+        return {
+            "vault": vault_name,
+            "path": path,
+            "title": file_path.name,
+            "tags": [],
+            "frontmatter": {},
+            "html": html,
+            "raw_length": size,
+            "extension": ext,
+            "is_markdown": False,
+            "is_image": True,
+            "image_mime": mime,
+            "size_bytes": size,
+        }
+
+    # === Audio / Video: HTML5 players streamed from /api/media (roadmap #109) ===
+    if is_audio(ext) or is_video(ext):
+        size = file_path.stat().st_size
+        mime = media_mime_type(str(file_path))
+        media_kind = "audio" if is_audio(ext) else "video"
+
+        # #109-A3 — beyond the inline limit the viewer falls back to download
+        # (a single uvicorn worker must not be pinned by multi-GB media).
+        if size > media_max_inline_bytes():
+            return {
+                "vault": vault_name,
+                "path": path,
+                "title": file_path.name,
+                "tags": [],
+                "frontmatter": {},
+                "html": "",
+                "raw_length": size,
+                "extension": ext,
+                "is_markdown": False,
+                "unsupported": True,
+                "media_too_large": True,
+                "size_bytes": size,
+            }
+
+        # #109-A2 — byte-range endpoint: enables scrub and is required by Safari.
+        stream_url = f"/api/media/{quote(vault_name, safe='')}?path={quote(path, safe='')}"
+        if media_kind == "audio":
+            html = (
+                f'<div class="audio-viewer">'
+                f'<audio controls preload="metadata" src="{stream_url}"></audio>'
+                f'</div>'
+            )
+        else:
+            html = (
+                f'<div class="video-viewer">'
+                f'<video controls playsinline preload="metadata" src="{stream_url}"></video>'
+                f'</div>'
+            )
+        return {
+            "vault": vault_name,
+            "path": path,
+            "title": file_path.name,
+            "tags": [],
+            "frontmatter": {},
+            "html": html,
+            "raw_length": size,
+            "extension": ext,
+            "is_markdown": False,
+            "is_audio": media_kind == "audio",
+            "is_video": media_kind == "video",
+            "media_mime": mime,
+            "stream_url": stream_url,
+            "size_bytes": size,
+        }
+
+    try:
+        raw = file_path.read_text(encoding="utf-8", errors="replace")
+    except PermissionError as e:
+        logger.error(f"Permission denied reading file {path}: {e}")
+        raise HTTPException(status_code=403, detail=f"Permission denied: cannot read file {path}")
+    except UnicodeDecodeError:
+        # Binary / unsupported file — return structured info with download option
+        size = file_path.stat().st_size
+        return {
+            "vault": vault_name,
+            "path": path,
+            "title": file_path.name,
+            "tags": [],
+            "frontmatter": {},
+            "html": "",
+            "raw_length": size,
+            "extension": ext,
+            "is_markdown": False,
+            "unsupported": True,
+            "size_bytes": size,
+        }
+    except Exception as e:
+        logger.error(f"Unexpected error reading file {path}: {e}")
+        raise HTTPException(status_code=500, detail=f"Error reading file: {e!s}")
+
+    # === CSV: render as HTML table ===
+    if ext == ".csv":
+        import csv
+        import io as csv_io
+        reader = csv.reader(csv_io.StringIO(raw))
+        rows = list(reader)
+        if not rows:
+            html = "<p><em>Fichier CSV vide</em></p>"
+        else:
+            headers = rows[0]
+            data_rows = rows[1:]
+            html = '<div class="csv-table-wrapper"><table class="csv-table"><thead><tr>'
+            for h in headers:
+                html += f"<th>{h}</th>"
+            html += "</tr></thead><tbody>"
+            for row in data_rows:
+                html += "<tr>"
+                for cell in row:
+                    html += f"<td>{cell}</td>"
+                html += "</tr>"
+            html += "</tbody></table></div>"
+        return {
+            "vault": vault_name, "path": path,
+            "title": file_path.name, "tags": [], "frontmatter": {},
+            "html": html, "raw_length": len(raw), "extension": ext,
+            "is_markdown": False, "is_csv": True,
+        }
+
+    # === JSON: syntax-highlighted display ===
+    if ext == ".json":
+        import json as json_mod
+        try:
+            parsed = json_mod.loads(raw)
+            formatted = json_mod.dumps(parsed, indent=2, ensure_ascii=False)
+        except json_mod.JSONDecodeError:
+            formatted = raw
+        html = f"<pre class='json-viewer'><code>{html_mod.escape(formatted)}</code></pre>"
+        return {
+            "vault": vault_name, "path": path,
+            "title": file_path.name, "tags": [], "frontmatter": {},
+            "html": html, "raw_length": len(raw), "extension": ext,
+            "is_markdown": False, "is_json": True,
+        }
+
+    # === Excalidraw .excalidraw.md (Obsidian plugin format) ===
+    if path.lower().endswith(".excalidraw.md"):
+        import re as re_mod
+        raw_lower = file_path.read_text(encoding="utf-8", errors="replace")
+        # Check for excalidraw-plugin in frontmatter or body
+        if "excalidraw-plugin:" in raw_lower:
+            # Extract compressed JSON block
+            match = re_mod.search(r'```compressed-json\n(.*?)\n```', raw_lower, re_mod.DOTALL)
+            if match:
+                compressed = match.group(1).strip()
+                return {
+                    "vault": vault_name, "path": path,
+                    "title": file_path.name.replace(".excalidraw.md", ""),
+                    "tags": [], "frontmatter": {},
+                    "html": "", "raw_length": len(raw_lower),
+                    "extension": ".excalidraw.md",
+                    "is_markdown": False,
+                    "is_excalidraw": True,
+                    "excalidraw_data_compressed": compressed,
+                }
+        # Fallback: treat as regular markdown
+        raw = raw_lower
+    if ext == ".excalidraw":
+        import json as json_mod
+        try:
+            parsed = json_mod.loads(raw)
+        except json_mod.JSONDecodeError:
+            parsed = None
+        if parsed and parsed.get("type") == "excalidraw":
+            return {
+                "vault": vault_name,
+                "path": path,
+                "title": parsed.get("appState", {}).get("name") or file_path.name,
+                "tags": [],
+                "frontmatter": {},
+                "html": "",
+                "raw_length": len(raw),
+                "extension": ext,
+                "is_markdown": False,
+                "is_excalidraw": True,
+                "excalidraw_data": {
+                    "elements": parsed.get("elements", []),
+                    "appState": parsed.get("appState", {}),
+                    "files": parsed.get("files", {}),
+                },
+            }
+        else:
+            # Not a valid Excalidraw file — fall through to text viewer
+            pass
+
+    # === Plain text / other readable files ===
+    TEXT_EXTENSIONS = {".txt", ".log", ".yml", ".yaml", ".toml", ".ini", ".cfg",
+                       ".sh", ".bash", ".py", ".js", ".ts", ".html", ".css",
+                       ".xml", ".rst", ".tex", ".sql", ".conf", ".env"}
+    if ext in TEXT_EXTENSIONS or ext == ".md":
+        pass  # handled below or by markdown section
+
+    if ext == ".md":
+        post = parse_markdown_file(raw)
+
+        # Extract metadata using shared indexer logic
+        tags = _extract_tags(post)
+
+        title = post.metadata.get("title", file_path.stem.replace("-", " ").replace("_", " "))
+        html_content = _render_markdown(post.content, vault_name, file_path)
+
+        return {
+            "vault": vault_name,
+            "path": path,
+            "title": str(title),
+            "tags": tags,
+            "frontmatter": dict(post.metadata) if post.metadata else {},
+            "html": html_content,
+            "raw_length": len(raw),
+            "extension": ext,
+            "is_markdown": True,
+        }
+    else:
+        # Non-markdown: wrap in syntax-highlighted code block
+        lang = EXT_TO_LANG.get(ext, "")
+        if not lang:
+            # Fichiers sans extension usuels (Dockerfile, Makefile, etc.)
+            NAME_TO_LANG = {
+                "dockerfile": "dockerfile", "makefile": "makefile",
+                "cmakelists.txt": "cmake", "jenkinsfile": "groovy",
+                "vagrantfile": "ruby", "rakefile": "ruby", "gemfile": "ruby",
+                "procfile": "plaintext", "bashrc": "bash", "bash_profile": "bash",
+                "zshrc": "bash", "profile": "bash", "gitignore": "plaintext",
+            }
+            lang = NAME_TO_LANG.get(file_path.name.lower(), "plaintext")
+        escaped = html_mod.escape(raw)
+        html_content = f'<pre><code class="language-{lang}">{escaped}</code></pre>'
+
+        return {
+            "vault": vault_name,
+            "path": path,
+            "title": file_path.name,
+            "tags": [],
+            "frontmatter": {},
+            "html": html_content,
+            "raw_length": len(raw),
+            "extension": ext,
+            "is_markdown": False,
+        }
diff --git a/backend/routers/helpers.py b/backend/routers/helpers.py
new file mode 100644
index 0000000..0465ba4
--- /dev/null
+++ b/backend/routers/helpers.py
@@ -0,0 +1,51 @@
+"""Shared helpers for the file routers (ROADMAP #85, tranche 6a).
+
+Petites fonctions pures extraites de :mod:`backend.main` sans changement
+de comportement. Regroupées ici car utilisées par plusieurs routers
+(``files_read`` aujourd'hui, ``files_media`` / mutations ensuite) :
+- :func:`content_disposition` — aussi utilisée par ``_stream_file_with_range``
+  (resté dans ``main`` jusqu'à la tranche media).
+- :func:`media_max_inline_bytes` — aussi utilisée par ``/api/media``.
+"""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+
+
+def content_disposition(disposition: str, filename: str) -> str:
+    """Build a header-safe Content-Disposition value.
+
+    HTTP header values must be ASCII. Unicode filenames are sent per
+    RFC 5987 via ``filename*`` (percent-encoded UTF-8) with a pure-ASCII
+    ``filename`` fallback. This avoids a UnicodeDecodeError / HTTP 500 when
+    the filename contains accented characters (e.g. 'Bière blonde…pdf').
+    """
+    from urllib.parse import quote
+    ascii_name = "".join(c for c in filename if c.isascii() and (c.isalnum() or c in " _-.")).strip() or "file"
+    ext = Path(filename).suffix
+    if ext and not Path(ascii_name).suffix:
+        ascii_name = ascii_name + ext
+    return f"{disposition}; filename=\"{ascii_name}\"; filename*=UTF-8''{quote(filename)}"
+
+
+def media_max_inline_bytes() -> int:
+    """Maximum size (bytes) for inline audio/video playback (roadmap #109-A3).
+
+    Configurable via ``OBSIGATE_MEDIA_MAX_INLINE_MB`` (default 500 MB). Files
+    above the limit are not streamed in the viewer (the UI falls back to the
+    download button), which keeps a single uvicorn worker from being pinned by
+    multi-gigabyte media. Invalid or non-positive values fall back to default.
+    """
+    default_mb = 500
+    raw = os.environ.get("OBSIGATE_MEDIA_MAX_INLINE_MB", "").strip()
+    if not raw:
+        return default_mb * 1024 * 1024
+    try:
+        mb = float(raw)
+    except ValueError:
+        return default_mb * 1024 * 1024
+    if mb <= 0:
+        return default_mb * 1024 * 1024
+    return int(mb * 1024 * 1024)
diff --git a/backend/schemas.py b/backend/schemas.py
index 19887a0..276704e 100644
--- a/backend/schemas.py
+++ b/backend/schemas.py
@@ -214,6 +214,73 @@ class RestoreResponse(BaseModel):
     current_backed_up: int | None = Field(default=None, description="Timestamp of the backup created from the current version before restore, if any")
 
 
+# ---------------------------------------------------------------------------
+# Files — browse / read (#85 — extrait de backend.main, inchangé)
+# ---------------------------------------------------------------------------
+
+
+class BrowseItem(BaseModel):
+    """A single entry (file or directory) returned by the browse endpoint."""
+
+    name: str = Field(description="File or directory name")
+    path: str = Field(description="Relative path within vault")
+    type: str = Field(description="'file' or 'directory'")
+    children_count: int | None = Field(default=None, description="Number of children (directories only)")
+    size: int | None = Field(default=None, description="File size in bytes")
+    extension: str | None = Field(default=None, description="File extension")
+
+
+class BrowseResponse(BaseModel):
+    """Paginated directory listing for a vault."""
+
+    vault: str
+    path: str
+    items: list[BrowseItem]
+
+
+class FileContentResponse(BaseModel):
+    """Rendered file content with metadata."""
+
+    vault: str = Field(description="Vault name")
+    path: str = Field(description="Relative file path within the vault")
+    title: str = Field(description="File title (from frontmatter or filename)")
+    tags: list[str] = Field(description="Extracted tags from frontmatter and inline #tags")
+    frontmatter: dict[str, Any] = Field(description="YAML frontmatter as key-value dict")
+    html: str = Field(description="Rendered HTML content")
+    raw_length: int = Field(description="Length of raw file content in characters")
+    extension: str = Field(description="File extension (e.g. .md, .txt)")
+    is_markdown: bool = Field(description="Whether the file is markdown")
+    unsupported: bool | None = Field(default=False, description="True for binary/unsupported files")
+    size_bytes: int | None = Field(default=None, description="File size in bytes (for unsupported files)")
+    is_pdf: bool | None = Field(default=None, description="True for PDF files")
+    is_image: bool | None = Field(default=None, description="True for image files")
+    is_audio: bool | None = Field(default=None, description="True for audio files (HTML5 <audio>, roadmap #109)")
+    is_video: bool | None = Field(default=None, description="True for video files (HTML5 <video>, roadmap #109)")
+    media_too_large: bool | None = Field(default=None, description="True when audio/video exceeds the inline streaming limit")
+    stream_url: str | None = Field(default=None, description="Byte-range streaming URL under /api/media (audio/video)")
+    media_mime: str | None = Field(default=None, description="MIME type for audio/video files")
+    is_csv: bool | None = Field(default=None, description="True for CSV files")
+    is_xlsx: bool | None = Field(default=None, description="True for Excel .xlsx files")
+    xlsx_sheets: list[dict[str, Any]] | None = Field(
+        default=None, description="Rendered xlsx sheets [{name, html}]"
+    )
+    is_json: bool | None = Field(default=None, description="True for JSON files")
+    is_excalidraw: bool | None = Field(default=None, description="True for Excalidraw diagram files")
+    excalidraw_data: dict[str, Any] | None = Field(default=None, description="Excalidraw diagram data (elements, appState, files)")
+    excalidraw_data_compressed: str | None = Field(default=None, description="Compressed Excalidraw data for .excalidraw.md files")
+    pdf_metadata: dict[str, Any] | None = Field(default=None, description="PDF metadata")
+    pdf_toc: list[dict[str, Any]] | None = Field(default=None, description="PDF table of contents")
+    image_mime: str | None = Field(default=None, description="MIME type for image files")
+
+
+class FileRawResponse(BaseModel):
+    """Raw text content of a file."""
+
+    vault: str = Field(description="Vault name")
+    path: str = Field(description="Relative file path within the vault")
+    raw: str = Field(description="Raw file content as text")
+
+
 # ---------------------------------------------------------------------------
 # Search / suggest / graph (#85 — extrait de backend.main, inchangé)
 # ---------------------------------------------------------------------------
diff --git a/desktop/Cargo.lock b/desktop/Cargo.lock
index d70b5ab..dc2415b 100644
--- a/desktop/Cargo.lock
+++ b/desktop/Cargo.lock
@@ -2626,7 +2626,7 @@ dependencies = [
 
 [[package]]
 name = "obsigate-desktop"
-version = "2.27.6"
+version = "2.27.7"
 dependencies = [
  "chrono",
  "env_logger",
diff --git a/desktop/Cargo.toml b/desktop/Cargo.toml
index f7a534e..f13f4df 100644
--- a/desktop/Cargo.toml
+++ b/desktop/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "obsigate-desktop"
-version = "2.27.6"
+version = "2.27.7"
 description = "ObsiGate Desktop — Porte d'entrée native pour vos vaults Obsidian"
 authors = ["Bruno Charest"]
 edition = "2021"
diff --git a/desktop/tauri.conf.json b/desktop/tauri.conf.json
index 589ce02..5f1f3e7 100644
--- a/desktop/tauri.conf.json
+++ b/desktop/tauri.conf.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://raw.githubusercontent.com/nicedoc/obsigate/main/desktop/tauri.conf.schema.json",
   "productName": "ObsiGate",
-  "version": "2.27.6",
+  "version": "2.27.7",
   "identifier": "com.obsigate.desktop",
   "build": {
     "frontendDist": "../frontend",
diff --git a/docs/ROADMAP.md b/docs/ROADMAP.md
index 16a3b96..b10183e 100644
--- a/docs/ROADMAP.md
+++ b/docs/ROADMAP.md
@@ -1,6 +1,6 @@
 # ObsiGate — Roadmap
 
-> **Version :** 2.27.6 | **Dernière mise à jour :** 2026-09-26
+> **Version :** 2.27.7 | **Dernière mise à jour :** 2026-09-26
 > **Ce fichier ne contient que le travail à venir** (🔵 En cours + ⚪ Backlog) et un index compact
 > vers les fonctionnalités livrées.
 > - **Méthode de livraison à appliquer pour toute tâche : [DELIVERY_WORKFLOW.md](./DELIVERY_WORKFLOW.md)**
@@ -67,10 +67,10 @@
 
 - **Effort :** 8-12 jours | **Impact :** 🟡 | **Zone :** backend
 - **Décision 2026-09-26 : prioritaire (axe Dette & sécurité).**
-- **Statut :** 🔵 en cours depuis 2026-09-26 — découpe par tranches à impact minimal (comportement inchangé, un domaine par commit). **T1 livrée (v2.27.2) :** `health` (`/api/health`, `/api/health/detailed` → `backend/routers/health.py`, `HealthResponse` → `schemas.py`). **T2 livrée (v2.27.3) :** `webhooks` (CRUD `/api/webhooks` → `backend/routers/webhooks.py`, logique déjà dans `backend/webhooks.py`). **T3 livrée (v2.27.4) :** `sharing` (`/api/share/*`, `/api/shares`, `/s/{token}*` → `backend/routers/sharing.py`, logique déjà dans `backend/share.py`). **T4 livrée (v2.27.5) :** `backups` (9 routes `/api/file/{vault}/backups|diff|restore` + `/api/backups*` → `backend/routers/backups.py`, `Diff/Restore*` → `schemas.py`, singleton SSE → `backend/sse.py`). **T5 livrée (v2.27.6) :** `search` (11 routes search/tags/suggest/graph/reload → `backend/routers/search.py`, modèles search → `schemas.py`, pool threads → `backend/search_executor.py`).
+- **Statut :** 🔵 en cours depuis 2026-09-26 — découpe par tranches à impact minimal (comportement inchangé, un domaine par commit). **T1 livrée (v2.27.2) :** `health` (`/api/health`, `/api/health/detailed` → `backend/routers/health.py`, `HealthResponse` → `schemas.py`). **T2 livrée (v2.27.3) :** `webhooks` (CRUD `/api/webhooks` → `backend/routers/webhooks.py`, logique déjà dans `backend/webhooks.py`). **T3 livrée (v2.27.4) :** `sharing` (`/api/share/*`, `/api/shares`, `/s/{token}*` → `backend/routers/sharing.py`, logique déjà dans `backend/share.py`). **T4 livrée (v2.27.5) :** `backups` (9 routes `/api/file/{vault}/backups|diff|restore` + `/api/backups*` → `backend/routers/backups.py`, `Diff/Restore*` → `schemas.py`, singleton SSE → `backend/sse.py`). **T5 livrée (v2.27.6) :** `search` (11 routes search/tags/suggest/graph/reload → `backend/routers/search.py`, modèles search → `schemas.py`, pool threads → `backend/search_executor.py`). **T6a livrée (v2.27.7) :** lecture fichiers (`/api/browse`, `/raw`, `/download`, `/backlinks`, `GET /api/file` → `backend/routers/files_read.py`, modèles + `EXT_TO_LANG` déplacés, helpers `_content_disposition`/`_media_max_inline_bytes` → `backend/routers/helpers.py`).
 - **Description :** extraire le monolithe `backend/main.py` (~4 827 lignes au 2026-09-26, ~17 % du backend) en routers FastAPI par domaine et rendre persistant l'état qui ne l'est pas (index de recherche, JTI révoqués, compteurs de rate-limit) pour préparer le multi-nœuds. L'état mémoire actuel (index, inverted index, vecteurs sémantiques, `SSEManager`, collab) rend le multi-workers unsafe.
 - **Sous-tâches :**
-  - [ ] Routers par domaine : files, search, share, webhooks, plugins, collab, admin, ai — `main.py` conservé comme assemblage (< 500 lignes) ; dédupliquer les modèles Pydantic vers `schemas.py`. **Avancement :** `health` ✅ (T1, `backend/routers/health.py`), `webhooks` ✅ (T2, `backend/routers/webhooks.py`), `sharing` ✅ (T3, `backend/routers/sharing.py`), `backups` ✅ (T4, `backend/routers/backups.py` + `backend/sse.py`), `search` ✅ (T5, `backend/routers/search.py` + `backend/search_executor.py`) ; `tools/registry.py` existe déjà (permissions/quotas/redaction — à compléter, pas à créer)
+  - [ ] Routers par domaine : files, search, share, webhooks, plugins, collab, admin, ai — `main.py` conservé comme assemblage (< 500 lignes) ; dédupliquer les modèles Pydantic vers `schemas.py`. **Avancement :** `health` ✅ (T1, `backend/routers/health.py`), `webhooks` ✅ (T2, `backend/routers/webhooks.py`), `sharing` ✅ (T3, `backend/routers/sharing.py`), `backups` ✅ (T4, `backend/routers/backups.py` + `backend/sse.py`), `search` ✅ (T5, `backend/routers/search.py` + `backend/search_executor.py`), `files-read` ✅ (T6a, `backend/routers/files_read.py` + `helpers.py`) ; `tools/registry.py` existe déjà (permissions/quotas/redaction — à compléter, pas à créer)
   - [ ] Compléter `tools/registry.py` (existant : permissions/quotas/redaction) comme contrat central des outils IA si des manques sont constatés
   - [ ] Persister index, JTI révoqués et compteurs de rate-limit (SQLite par défaut, Redis en option multi-nœuds ; le rate-limit actuel est in-memory mono-process)
   - [ ] Verrous asyncio autour de l'index global et des stores JSON ; auditer les `except Exception` larges (> 100 occurrences) : best-effort (backup/audit) vs masquage d'erreur (erreurs typées 4xx/5xx + test)
diff --git a/package.json b/package.json
index d38b5fa..9f286de 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "obsigate",
-  "version": "2.27.6",
+  "version": "2.27.7",
   "description": "**Porte d'entrée web ultra-léger pour vos vaults Obsidian** — Accédez, naviguez et recherchez dans toutes vos notes Obsidian depuis n'importe quel appareil via une interface web moderne et responsive.",
   "main": "patch.js",
   "directories": {