Status Codes

Nucleus uses standard HTTP status codes with a JSON body.

Code	Meaning	Body
200	Success	{"status":"ok", ...}
400	Bad request — missing/invalid param	{"status":"error","message":"..."}
404	Not found (e.g. invalid PNR, unknown PIN)	{"status":"not_found","message":"..."}
500	Server error	{"status":"error","message":"..."}
502	Upstream provider error	{"status":"error","message":"..."}
503	Database unavailable	{"status":"error","message":"db down"}

Error Format

All errors follow the same shape:

{
  "status": "error",
  "message": "Human-readable explanation"
}

For most APIs an extra api field tells you which service failed:

{
  "status": "error",
  "api": "weather",
  "message": "Unknown city. Available: kolkata, mumbai, delhi..."
}