[backend] Health Check Endpoint (Supabase + Stellar)

[josueazc]

DESCRIPTION

There is no way to verify that the API's external dependencies (Supabase and Stellar testnet) are reachable and healthy. Without a health endpoint, Railway's deployment checks pass blindly and external monitoring tools cannot observe the system. This task adds GET /api/health returning structured connectivity status.

GOAL

GET /api/health returns a structured JSON status of Supabase and Stellar connectivity, with HTTP 200 when healthy or 503 when any dependency is down.

REQUIREMENTS

• GET /api/health — no authentication required
• Checks: Supabase reachability (simple DB ping), Stellar Horizon reachability
• Response shape: { status: 'ok'|'degraded', supabase: 'up'|'down', stellar: 'up'|'down', uptime: seconds }
• HTTP 200 when all up, HTTP 503 when any dependency is down
• 3-second timeout per dependency check to avoid hanging

ACCEPTANCE CRITERIA

• GET /api/health returns 200 with { status: 'ok', ... } in normal operation
• Response includes supabase and stellar status fields
• Response time is under 5s in normal operation
• Endpoint is unauthenticated (no JWT required)
• Work follows Velar monorepo structure
• No existing endpoints are affected
• Can be reviewed by the team

NOTES

Relevant files: apps/api/src/app.controller.ts or a new apps/api/src/health/ module. Good first task — no blockchain knowledge required. Consider @nestjs/terminus for structured health checks. Railway uses health checks to determine deployment success.

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Difficulty: Beginner
Priority: Low

[iamayushtiwari]

hi @josueazc ,
I would love to work on this issue. Could you please assign it to me?I have reviewed the description and feel confident I can implement the required changes. If you have any specific pointers or preferences before I start, please let me know.

[sibaja0225]

I'm interested because it matches my backend experience, and I'd like to contribute while learning more about Supabase and Stellar.

[grantfox-oss]

🦊 GrantFox — @sibaja0225 has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #5)
2. Your PR will be reviewed by the Velar-Bonds maintainers

Good luck! Track your progress on GrantFox.