diff --git a/pyproject.toml b/pyproject.toml
index 3e06aae..76c962e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.backends._legacy:_Backend"
 
 [project]
 name = "t2a"
-version = "2.0.0"
+dynamic = ["version"]
 description = "Pipeline de codage CIM-10/CCAM automatise pour le PMSI hospitalier"
 readme = "README.md"
 requires-python = ">=3.11"
@@ -43,6 +43,9 @@ dev = [
 [project.scripts]
 t2a = "src.main:main"
 
+[tool.setuptools.dynamic]
+version = {attr = "src.__version__.__version__"}
+
 [tool.setuptools.packages.find]
 include = ["src*"]
 
diff --git a/src/__version__.py b/src/__version__.py
new file mode 100644
index 0000000..fb8cbb7
--- /dev/null
+++ b/src/__version__.py
@@ -0,0 +1,3 @@
+"""Version unique du projet T2A v2 (single source of truth)."""
+
+__version__ = "2.1.0"
diff --git a/src/viewer/app.py b/src/viewer/app.py
index a78d99d..101bb0f 100644
--- a/src/viewer/app.py
+++ b/src/viewer/app.py
@@ -22,6 +22,7 @@ from ..config import (
     ALLOWED_EXTENSIONS, UPLOAD_MAX_SIZE_MB,
 )
 from .. import config as cfg
+from ..__version__ import __version__ as APP_VERSION
 from ..control.cpam_context import _assess_dossier_strength
 from ..medical.bio_normals import BIO_NORMALS
 from .referentiels import ReferentielManager
@@ -102,7 +103,12 @@ def create_app() -> Flask:
                     rep = item
                     break
             dossier_list.append({"name": format_dossier_name(group_name), "path": rep["path_rel"]})
-        return {"dossier_list": dossier_list}
+        return {"dossier_list": dossier_list, "app_version": APP_VERSION}
+
+    # --- Health check ---
+    @app.route("/health")
+    def health():
+        return jsonify({"status": "ok", "version": APP_VERSION})
 
     # ===================================================================
     # Routes principales
diff --git a/src/viewer/templates/base.html b/src/viewer/templates/base.html
index a9320af..9b7da04 100644
--- a/src/viewer/templates/base.html
+++ b/src/viewer/templates/base.html
@@ -421,6 +421,9 @@
     <input type="text" id="sidebar-search" placeholder="Rechercher un dossier…" autocomplete="off">
     <div id="sidebar-autocomplete" style="display:none;position:absolute;left:0;right:0;background:#0f172a;border:1px solid #475569;border-radius:0 0 6px 6px;max-height:250px;overflow-y:auto;z-index:100;"></div>
   </div>
+  <div style="padding:0.5rem 1rem;border-top:1px solid #334155;font-size:0.6rem;color:#475569;text-align:center;">
+    v{{ app_version }}
+  </div>
 </aside>
 
 <!-- Main -->