Topology
Studio, demo and docs run on Vercel. API, worker, PostgreSQL and Redis run on Railway. R2 is durable artifact storage; Redis is never a source of truth.
Release order
Restore-test backup, deploy migrations, verify /ready, deploy worker then API, and finally frontends. Roll out Behavior changes through shadow and targeted canary.
Rollback
Application rollback creates a new deployment event pointing to an old exact revision. Infrastructure rollback uses the previous immutable platform deployment.