convex-migration-helper

Convex zero-downtime migrations use a widen-migrate-narrow strategy: widen the schema to support both old and new shapes, backfill data in batches, then narrow the schema to complete the breaking change safely.

Online data backfills in Convex are best handled using the @convex-dev/migrations component, which supports robust, resumable workflows that process data in batches to keep your application available during migration windows.

The @convex-dev/migrations component handles table reshaping by providing robust, resumable migration workflows across production and development environments, ensuring data integrity during batch processing.

Yes, you can safely run batch migrations on Convex production environments by using online migrations that process data incrementally, ensuring the application remains available throughout the migration window.

You need to use a widening migration path in Convex when applying breaking changes to your schema, allowing you to support both old and new data shapes simultaneously before narrowing the schema to finalize the update.