I Built a MongoDB Migration Tool After One Bad Deploy

Santosh Gupta — Sat, 06 Jun 2026 07:15:09 +0000

A few months ago I shipped a bad MongoDB migration.

Classic mistake.

I had run 3 migrations.

The third one had a bug.

I only wanted to rollback that migration.

Turns out with migrate-mongo, rollback is mostly:

undo the last applied migration

Which sounds fine until you have:

multiple deployments
multiple environments
teammates deploying too

“Last applied” stops feeling obvious.

I ended up manually undoing DB changes and fixing migration history myself.

Not fun.

That was the moment I realized our migration setup had started breaking down as the project grew.

The stuff I kept wishing existed

After that incident I wrote down all the things I wanted from a migration tool:

run one migration file
rollback a specific migration
preview migrations before running (dry-run)
avoid concurrent deploys stepping on each other (locking)
detect edited migrations (checksums)
a redo command for local development
TypeScript support without setup pain
migration history that doesn’t disappear after rollback

None of these felt unusual.

They felt like things you eventually want once your project stops being small.

So I ended up building one.

Meet `mongo-migrate-kit`

CLI name: mmk

A few examples:

Run pending migrations:

mmk up

Rollback a specific migration:

mmk down migration-name

Preview before touching production:

mmk up --dry-run

Redo during development:

mmk redo

The hard problem: switching tools safely

This was the part I cared about most.

Migration tools are easy to adopt on day 1.

They’re painful to switch after 50+ migrations already exist.

I didn’t want people to:

rerun old migrations
recreate indexes
duplicate seed data
accidentally touch production data

So I added:

mmk import

It reads your existing migrate-mongo changelog and adopts the migration history.

Then:

mmk up

only runs new migrations.

No replaying old history.

No scary production moments.

One thing I intentionally don't support

Imported migrate-mongo migrations are forward-only.

You can’t rollback imported migrations using mmk.

I could have tried to force compatibility, but I didn’t trust it enough to be safe.

Different execution models + database tooling = not something I wanted to gamble with.

So the tool fails loudly instead of pretending everything is reversible.

Curious what other teams are doing

If you're running MongoDB migrations in production:

What’s your current setup?
Have you hit similar pain points?
Are you still happy with migrate-mongo?

Would genuinely love feedback.

Project:

mongo-migrate-kit

Docs/demo:
mongo-migrate-kit.vercel.app

npm:
mongo-migrate-kit