diff --git a/CHANGELOG.md b/CHANGELOG.md
index d580db8..4ec7de6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Fixed
+- Fixed `ProgrammingError` (`cached statement plan is invalid`) raised by the asyncpg dialect during startup: SQLAlchemy's asyncpg wrapper maintains an LRU prepared-statement cache per connection (default size 100). When `Base.metadata.create_all()` executes `CREATE TYPE … AS ENUM` DDL inside a transaction, PostgreSQL invalidates the cached plans for that connection. The next enum-type existence check then fails because the dialect tries to reuse the now-stale prepared statement. Fix: set `prepared_statement_cache_size=0` in `connect_args` on `create_async_engine` to disable the cache entirely, which is the documented SQLAlchemy recommendation for DDL-at-startup scenarios.
 - Fixed `UndefinedTableError` on first boot: the lifespan startup event now calls `Base.metadata.create_all()` via the async engine before attempting to seed default settings, so all tables are created automatically when the database is empty (e.g., fresh PostgreSQL container with no Alembic migrations run yet).
 - Fixed frontend API calls being hardcoded to `http://localhost:8000` in production: `NEXT_PUBLIC_API_URL` is baked into the JavaScript bundle at Next.js build time, so it can never be overridden at container runtime. Replaced the `NEXT_PUBLIC_API_URL` mechanism with a Next.js Route Handler proxy at `/api/v1/[...path]` that reads `process.env.BACKEND_URL` at server startup and proxies all `/api/v1/*` requests to the real backend. The frontend Axios client now uses a relative base URL (`/api/v1`), which also eliminates the CORS issue since the browser only ever talks to the same-origin Next.js server. Update `BACKEND_URL=http://backend:8000` in `docker-compose.new.yml` (or your deployment env) to point the proxy at your backend.
 - Fixed infinite spinning wheel on the home page: `authStore` no longer initialises `isLoading` as `true` unconditionally — it is now `false` when no access token exists in `localStorage`, so unauthenticated users see the landing page immediately instead of an endless spinner
diff --git a/backend/app/core/database.py b/backend/app/core/database.py
index dba292c..05f8c8a 100644
--- a/backend/app/core/database.py
+++ b/backend/app/core/database.py
@@ -9,12 +9,17 @@ from sqlalchemy.orm import declarative_base
 from app.core.config import settings
 
 # Create async engine
+# prepared_statement_cache_size=0 disables SQLAlchemy's asyncpg prepared-statement
+# LRU cache. This prevents ProgrammingError("cached statement plan is invalid") when
+# CREATE TYPE / CREATE TABLE DDL (run via create_all at startup) invalidates previously
+# cached statement plans on the same connection.
 engine = create_async_engine(
     settings.DATABASE_URL,
     echo=settings.DEBUG,
     pool_size=settings.DATABASE_POOL_SIZE,
     max_overflow=settings.DATABASE_MAX_OVERFLOW,
     pool_pre_ping=True,
+    connect_args={"prepared_statement_cache_size": 0},
 )
 
 # Create async session factory
diff --git a/docs/TODO.md b/docs/TODO.md
index d0d3797..7e0244d 100644
--- a/docs/TODO.md
+++ b/docs/TODO.md
@@ -101,6 +101,7 @@ Comprehensive task breakdown for repository improvements and production readines
 - [x] Fix frontend API URL hardcoded to `localhost:8000` in production: replaced build-time `NEXT_PUBLIC_API_URL` with a runtime Next.js Route Handler proxy (`/api/v1/[...path]`) reading `BACKEND_URL` at server startup
 - [x] Log `BACKEND_URL` at frontend server startup and include target URL in per-request proxy error messages
 - [x] Fix `UndefinedTableError` on first boot: lifespan event now runs `Base.metadata.create_all()` so tables are created automatically when no migrations have been applied
+- [x] Fix `ProgrammingError` (cached statement plan is invalid) during startup: set `prepared_statement_cache_size=0` on the asyncpg engine to prevent plan invalidation when `CREATE TYPE` DDL runs at startup
 
 ### In Progress 🔨
 - [ ] Configure branch protection rules