# ADS-B Source

ADS-B Exchange support is optional and intended for unfiltered aircraft and military-flight awareness.

- Source module: `apis/sources/adsb.mjs`
- Preferred provider: ADS-B Exchange via RapidAPI
- Credentials: `ADSB_API_KEY` or `RAPIDAPI_KEY`
- Runtime status without credentials: `disabled`
- Runtime status when providers fail: `degraded`
- Runtime status with usable aircraft payloads: `live`

The source does not treat a missing key or unavailable public feed as normal live data. `/api/health` and `/api/metrics` surface the degraded source state through the sweep source summary.

Known failure modes:

- Missing `ADSB_API_KEY` / `RAPIDAPI_KEY`: source is disabled with operator guidance.
- RapidAPI rejects or rate-limits the request: source is degraded and records provider failure detail.
- Public feed is blocked, rate-limited, or changes shape: source remains degraded instead of returning stale-looking data.

Register for the provider documented in the README, then set:

```env
ADSB_API_KEY=<rapidapi-key>
```