supaschema and Atlas both manage schema as code, but they aim at different scopes. supaschema is a PostgreSQL tool that generates a replay-safe migration from declarative SQL and proves it locally, against any Postgres provider (self-hosted, RDS/Aurora, Cloud SQL, AlloyDB, Neon, Azure, or Supabase). Atlas is a broader multi-database schema-as-code platform whose migration linting and custom policy rules moved to the paid Atlas Pro tier.
Short answer
Usesupaschema when you want free, Postgres-native migration generation plus replay-safety and lock-hazard checks from declarative SQL, with no Docker or shadow database. Use Atlas when you want its multi-database platform and hosted reporting and you are willing to pay for Atlas Pro to keep atlas migrate lint.
Comparison
| Capability | supaschema | Atlas |
|---|---|---|
| Migration-safety linting cost | Free (supaschema check) | atlas migrate lint is Atlas Pro only since v0.38 (2025-10-28) |
| Custom policy linting | Free rule packs in scan | Schema-policy rules are Atlas Pro only |
| Database focus | Any PostgreSQL database (any provider) | Many database engines |
| Parser | PostgreSQL’s parser (libpg_query) compiled to WebAssembly | Its own multi-engine schema engine |
| Docker or shadow database | Not required | Often used for diffing |
| RLS policy body changes | Compared structurally | Postgres RLS coverage varies by feature |
| Generated types | TypeScript and Zod from the schema files | Not the same generated-type workflow |
| Apply to production | No, generation and proof only | Yes, Atlas applies migrations |
Why the workflow differs
supaschema parses declarative SQL into PostgreSQL parse trees and renders a guarded migration from the structural difference, then supaschema check flags replay-safety and lock hazards. Those safety checks are in the free core. Grant and RLS safety run through free scan and deploy-safety gates; the licensed standalone CLI gate is type-contract --enforce.
Atlas is a larger platform that spans multiple database engines and adds hosted reporting and CI integration. Starting with Atlas v0.38, atlas migrate lint and the custom schema-policy rule language require Atlas Pro. Atlas’s current pricing pages describe separate CLI seat, pipeline project, and target-database pricing. If migration linting was the reason you used Atlas and you want a free Postgres-native option, supaschema check covers that lane.
Atlas pricing and feature gating are set by Atlas and can change. Last verified 2026-06-18 against the Atlas documentation; confirm current terms before relying on them.
Atlas lint is paid: free alternatives
The free Postgres migration-safety options after the v0.38 change.
The check command
The replay-safety and lock-hazard diagnostics supaschema runs for free.
Sources
- Atlas, “Verifying Migration Safety” —
atlas migrate lintis Atlas Pro only since v0.38. - Atlas v0.38 release notes (2025-10-28)
- Atlas pricing