diff --git a/server/pyproject.toml b/server/pyproject.toml
index 49648d6..d07f9a9 100644
--- a/server/pyproject.toml
+++ b/server/pyproject.toml
@@ -7,4 +7,5 @@ dependencies = [
     "uvicorn[standard]>=0.29",
     "pydantic>=2.0",
     "PyJWT>=2.8",
+    "cryptography>=42",
 ]
diff --git a/server/server.py b/server/server.py
index 815a00a..2619f57 100644
--- a/server/server.py
+++ b/server/server.py
@@ -1,13 +1,15 @@
 """BincioPlanner API — save/load route plans.
 
-Auth: validates bincio_session JWT issued by bincio-auth (HS256, shared secret).
+Auth: validates bincio_session JWT from bincio-auth.
+      Accepts RS256 OIDC tokens (BINCIO_OIDC_ISSUER) and HS256 session tokens (BINCIO_AUTH_JWT_SECRET).
 Storage: JSON files at $PLANS_DIR/{handle}/{plan_id}.json
          Collections: $PLANS_DIR/{handle}/_collections.json
          Shared plans: $PLANS_DIR/_shared/{plan_id}.json  (any authed user can read/write/delete)
 
 Run: uvicorn server:app --host 127.0.0.1 --port 8002
 Env vars:
-  BINCIO_AUTH_JWT_SECRET  HS256 secret shared with bincio-auth (required in production)
+  BINCIO_OIDC_ISSUER      OIDC issuer URL — JWKS fetched from {issuer}/.well-known/jwks.json
+  BINCIO_AUTH_JWT_SECRET  HS256 fallback secret
   PLANS_DIR               root dir for plan JSON files  (default: /var/bincio_planner)
   DEV_HANDLE              bypass auth in local dev
 """
@@ -18,23 +20,39 @@ import os
 import re
 import secrets
 import time
+import urllib.request
 from dataclasses import dataclass
 from pathlib import Path
 from typing import Optional
 
 import jwt as _jwt
+from jwt.algorithms import RSAAlgorithm as _RSAAlgorithm
 from fastapi import Cookie, Depends, FastAPI, HTTPException, Query
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.middleware.gzip import GZipMiddleware
 from fastapi.responses import JSONResponse
 from pydantic import BaseModel
 
-_JWT_SECRET = os.environ.get("BINCIO_AUTH_JWT_SECRET", "")
-_PLANS_DIR  = Path(os.environ.get("PLANS_DIR", "/var/bincio_planner"))
-_DEV_HANDLE = os.environ.get("DEV_HANDLE", "")
+_JWT_SECRET  = os.environ.get("BINCIO_AUTH_JWT_SECRET", "")
+_OIDC_ISSUER = os.environ.get("BINCIO_OIDC_ISSUER", "")
+_PLANS_DIR   = Path(os.environ.get("PLANS_DIR", "/var/bincio_planner"))
+_DEV_HANDLE  = os.environ.get("DEV_HANDLE", "")
 
 _SAFE_ID = re.compile(r"^[A-Za-z0-9_-]{1,32}$")
 
+# Load RS256 public key from JWKS at startup.
+_rs256_key = None
+if _OIDC_ISSUER:
+    try:
+        with urllib.request.urlopen(f"{_OIDC_ISSUER}/.well-known/jwks.json", timeout=5) as _r:
+            _jwks = json.loads(_r.read())
+        for _k in _jwks.get("keys", []):
+            if _k.get("kty") == "RSA":
+                _rs256_key = _RSAAlgorithm.from_jwk(json.dumps(_k))
+                break
+    except Exception as _e:
+        print(f"Warning: could not load JWKS from {_OIDC_ISSUER}: {_e}")
+
 
 # ── Auth ───────────────────────────────────────────────────────────────────────
 
@@ -45,6 +63,19 @@ class User:
 
 
 def _decode_session(token: str) -> Optional[User]:
+    # Try RS256 (OIDC id_token from bincio-auth)
+    if _rs256_key:
+        try:
+            payload = _jwt.decode(token, _rs256_key, algorithms=["RS256"],
+                                  options={"verify_aud": False})
+            handle = payload.get("sub")
+            if handle and payload.get("activity_access"):
+                return User(handle=handle,
+                            display_name=payload.get("name") or payload.get("display_name") or handle)
+        except _jwt.PyJWTError:
+            pass
+
+    # Fall back to HS256 session token
     if not _JWT_SECRET:
         return None
     try:
@@ -52,9 +83,7 @@ def _decode_session(token: str) -> Optional[User]:
     except _jwt.PyJWTError:
         return None
     handle = payload.get("sub")
-    if not handle:
-        return None
-    if not payload.get("activity_access"):
+    if not handle or not payload.get("activity_access"):
         return None
     return User(handle=handle, display_name=payload.get("display_name", handle))