# ADR 0001: Synchronous External Calls For MVP

## Status
Accepted

## Context
OTP sends, booking notifications, and payment provider calls were needed quickly for MVP reliability. Running queue infrastructure early would add operational overhead.

## Decision
Keep external calls synchronous in request/response paths for MVP, with explicit timeouts and failure handling.

## Consequences
- Faster delivery, fewer moving pieces.
- Higher latency risk when providers are slow.
- Payment/OTP failures surface to clients immediately.
- Notification failures are recorded (`FAILED`) and monitored, not returned to client requests.

## Alternatives Considered
- Full queue (Celery/Redis): deferred.
- Hybrid queue for notifications only: valid future step when latency/throughput needs it.

## Related
- `docs/architecture.md`
- `docs/runbooks/auth_otp_failures.md`
- `docs/runbooks/payments_sanity_check.md`