See the lock a Postgres migration takes before you merge it.

Migration Guard is a planned GitHub check. On a pull request that changes SQL migrations, it will post one comment per PR: which statements take which Postgres lock, what that lock blocks, and a lower-risk rewrite where one exists. It will link the PostgreSQL documentation for each lock.

Status: Early access. Not built yet: the GitHub Action is not started; we will build it if early-access demand is there.

Join early access

Who it is for

Backend engineers and tech leads who review Postgres migration .sql files in GitHub pull requests.

How it will work

1. Add the GitHub Action to your repo.
2. Open a PR that touches migration .sql files.
3. Read one comment listing each statement's lock, what it blocks, and a lower-risk rewrite.

See an example

Hand-written illustrations of the report format (the Action is not built yet):

• ADD COLUMN with a DEFAULT
• CREATE INDEX without CONCURRENTLY
• ALTER COLUMN TYPE

What it will not do

It will never say a migration is "safe". It uses a fixed rule list; statements it does not recognise are marked for review. It will not know your table sizes in the first version.

Price

$19 per repo per month early-access price. This is a planned price, not yet charged. Nothing is charged when you join early access.

Free alternative

Squawk is a free open-source linter for Postgres migrations (github.com/sbdchd/squawk). We are testing whether plain-language lock explanations and rewrites are worth paying for. Squawk is a separate project and is not affiliated with us.