Show HN: Scry – Test migrations against production scale copy of your DB

We built a tool that catches migration regressions before production by replaying real query traffic against shadow databases.

The blog post walks through a concrete example: a missing index that causes a 92x regression on a core query path. Staging misses it because it has 100 rows instead of 25k. Scry catches it because it replays actual production queries at real data scale.

You can replay this exact scenario locally in under 2 minutes:

scry demo Install: https://github.com/scrydata/scry-cli/releases

The demo spins up a source Postgres, applies a migration with a missing index, replays captured traffic, and shows you the regression report. No cloud account needed — everything runs locally.

Happy to answer questions about the architecture (transparent PG proxy for query capture, CDC replication for shadow databases, NATS for event streaming).