SafeNotSafe tells you if your Postgres migration will lock up production
Is your Postgres migration safe or not safe?
SafeNotSafe is a command-line tool that parses migration.sql with libpg_query 17 (WASM) and flags each statement as SAFE or risky. It catches common Postgres traps: constant column defaults that don't rewrite rows, concurrent index builds that avoid blocking writes, and constraint validation designed for safer rollouts. Run npx safe-not-safe check migration.sql to see per-statement verdicts before your migration hits production.
SAFE— No blocking pattern found. The checked statements avoid the common lock, rewrite, and rollout traps in the launch rule set.