Run PostgreSQL online

PostgreSQL is the SQL database the industry defaults to when correctness, concurrency, and features matter — CTEs, window functions, JSONB, full-text search, generated columns, partitioning, and strict type enforcement.

ls-judge runs a real PostgreSQL 17 server inside a Firecracker microVM. Every submission gets its own cluster seeded with a `playground` database (users + orders fixtures); each run is ephemeral — writes vanish when the VM dies, so you can CREATE, INSERT and DROP freely.

What you get in PostgreSQL

Clicking "Run now" opens the playground with this exact code and a matching test case pre-loaded — passes on first Run.

SELECT 'Hello, World!';

Common questions about PostgreSQL on ls-judge

Which version?

PostgreSQL 17 — the current stable major (released Sept 2024).

Pre-loaded data?

Yes — database `playground` with tables users(id, name, email) and orders(id, user_id, total, placed_at). Drop and recreate as you like.

Persistent DB?

No — the cluster is destroyed when the VM is torn down. Great for safe experimentation.

Extensions?

Only what ships with the Alpine postgresql17 package (standard contrib — pg_stat_statements, pgcrypto, etc.). No pgvector in v1.

Free?

Yes.

• PostgreSQL documentation↗