diff --git a/services/sofiia-console/app/idempotency.py b/services/sofiia-console/app/idempotency.py
index 32ec20f7..f8b90266 100644
--- a/services/sofiia-console/app/idempotency.py
+++ b/services/sofiia-console/app/idempotency.py
@@ -2,10 +2,13 @@ from __future__ import annotations
 
 import os
 import time
+import json
 from collections import OrderedDict
 from dataclasses import dataclass
 from typing import Any, Dict, Optional, Protocol
 
+from .logging import log_event
+
 
 @dataclass
 class ReplayEntry:
@@ -71,9 +74,62 @@ class InMemoryIdempotencyStore:
         self._values.clear()
 
 
+class RedisIdempotencyStore:
+    def __init__(self, redis_client: Any, ttl_seconds: int = 900, prefix: str = "sofiia:idem:") -> None:
+        self._redis = redis_client
+        self._ttl_seconds = max(60, int(ttl_seconds))
+        self._prefix = str(prefix or "sofiia:idem:")
+
+    def _k(self, key: str) -> str:
+        return f"{self._prefix}{key}"
+
+    def get(self, key: str) -> Optional[ReplayEntry]:
+        raw = self._redis.get(self._k(key))
+        if raw is None:
+            return None
+        if isinstance(raw, bytes):
+            raw = raw.decode("utf-8", errors="ignore")
+        try:
+            payload = json.loads(str(raw))
+        except Exception:
+            return None
+        if not isinstance(payload, dict):
+            return None
+        return ReplayEntry(
+            message_id=str(payload.get("message_id") or ""),
+            response_body=dict(payload.get("response_body") or {}),
+            created_at=float(payload.get("created_at") or 0.0),
+            node_id=str(payload.get("node_id") or ""),
+        )
+
+    def set(self, key: str, entry: ReplayEntry) -> None:
+        payload = {
+            "message_id": entry.message_id,
+            "response_body": entry.response_body,
+            "created_at": float(entry.created_at),
+            "node_id": entry.node_id,
+        }
+        self._redis.set(self._k(key), json.dumps(payload, ensure_ascii=True), ex=self._ttl_seconds)
+
+    # Debug/test helpers
+    def delete(self, key: str) -> None:
+        self._redis.delete(self._k(key))
+
+    def reset(self) -> None:
+        keys = self._redis.keys(f"{self._prefix}*")
+        if keys:
+            self._redis.delete(*keys)
+
+
 _STORE: Optional[IdempotencyStore] = None
 
 
+def _make_redis_client(redis_url: str) -> Any:
+    import redis  # type: ignore
+
+    return redis.Redis.from_url(redis_url, decode_responses=False)
+
+
 def get_idempotency_store() -> IdempotencyStore:
     global _STORE
     if _STORE is None:
@@ -83,7 +139,25 @@ def get_idempotency_store() -> IdempotencyStore:
                 os.getenv("CHAT_IDEMPOTENCY_TTL_SEC", "900"),
             )
         )
-        max_size = int(os.getenv("SOFIIA_IDEMPOTENCY_MAX", "5000"))
-        _STORE = InMemoryIdempotencyStore(ttl_seconds=ttl, max_size=max_size)
+        backend = os.getenv("SOFIIA_IDEMPOTENCY_BACKEND", "inmemory").strip().lower() or "inmemory"
+        if backend == "redis":
+            redis_url = os.getenv("SOFIIA_REDIS_URL", "redis://localhost:6379/0").strip()
+            prefix = os.getenv("SOFIIA_REDIS_PREFIX", "sofiia:idem:").strip() or "sofiia:idem:"
+            try:
+                client = _make_redis_client(redis_url)
+                _STORE = RedisIdempotencyStore(client, ttl_seconds=ttl, prefix=prefix)
+            except Exception as exc:
+                max_size = int(os.getenv("SOFIIA_IDEMPOTENCY_MAX", "5000"))
+                _STORE = InMemoryIdempotencyStore(ttl_seconds=ttl, max_size=max_size)
+                log_event(
+                    "idempotency.backend.fallback",
+                    backend="redis",
+                    status="degraded",
+                    error_code="redis_unavailable",
+                    error=str(exc)[:180],
+                )
+        else:
+            max_size = int(os.getenv("SOFIIA_IDEMPOTENCY_MAX", "5000"))
+            _STORE = InMemoryIdempotencyStore(ttl_seconds=ttl, max_size=max_size)
     return _STORE
 
diff --git a/services/sofiia-console/requirements.txt b/services/sofiia-console/requirements.txt
index 71ba37d6..9c24b35c 100644
--- a/services/sofiia-console/requirements.txt
+++ b/services/sofiia-console/requirements.txt
@@ -5,6 +5,7 @@ python-multipart>=0.0.6
 pyyaml>=6.0
 python-dotenv>=1.0.0
 prometheus-client>=0.20.0
+redis>=5.0.0
 # Projects / Documents / Sessions persistence (Phase 1: SQLite)
 aiosqlite>=0.20.0
 # Document text extraction (optional — used when available)