ADR-004: Neon Postgres for mvs-pay extensions DB

Status

Accepted (2026-05-28)

Context

The dedicated mvs-pay extensions DB needs Postgres-wire compatibility, branch-friendly dev/staging, and PITR.

Decision

Neon Postgres. Two projects: hyperswitch-prod (Hyperswitch router DB) and mvs-pay-extensions-prod (MVS extension data).

Consequences

  • Branchable for staging/preview environments.
  • PITR built-in.
  • PgBouncer connection pooling required to handle Vercel cold-start connection storms.
  • Cross-region replica deferred (single-region today).

Alternatives considered

  • AWS RDS: more enterprise-standard but no native branching; more operational overhead.
  • Aurora Serverless v2: scales well but expensive at low volume.