A browser-local checker flags unsafe PostgreSQL migrations using the real Postgres parser compiled to WebAssembly

Sources: primary, discussion
Summary: The tool compiles libpg_query to WebAssembly and runs it in a browser worker, so migration SQL is parsed rather than pattern-matched and never leaves the page, with no API route, no logs and no account. Verdicts are conditioned on row count and on whether the migration tool wraps DDL in a transaction, which is what separates a safe statement from a table-locking one in practice. The sample buffer shows the distinction it is built around, CREATE INDEX CONCURRENTLY and a foreign key added NOT VALID then validated in a second statement.
Why it matters: The page states SQL never leaves the browser, with no API route, no logs and no account, so a migration from a private repository can be checked against the real parser rather than a regex. No command-line or CI form is offered, and the npx line on the page is demo text inside a mock terminal pane rather than a published package.