# An AI translation layer can shrink a database migration from months to days

- Category: product
- Author: Mihai Negrea (https://indie.md/people/mihai-negrea/)
- Source: https://indie.md/journeys/mihai-datadriven/
- Canonical URL: https://indie.md/advice/use-ai-to-derisk-a-database-migration/

Migrating from Cosmos DB to MongoDB is the kind of project that haunts a solo founder, so Mihai turned it into a verification problem instead of a rewrite. He had Claude build a translation layer for his queries, then ran the old Cosmos path and the new Mongo path in parallel, with automated validation comparing outputs until the two systems agreed on everything. Once parity held, the cutover was boring, and the whole thing took two to three days. The pattern generalizes beyond databases: when replacing a load-bearing component, do not aim for a heroic big-bang rewrite, aim for a shim that lets old and new run side by side while machines check the diff. AI assistants are unusually good at generating exactly this kind of mechanical translation code that nobody wants to write by hand.