# Introduction

Baler is an ontology-agnostic building data platform: API-first,
load-time-pluggable (Brick/Haystack/DBO), headless by design. Time-series
readings live in Postgres/TimescaleDB — so Grafana, or anything else that
speaks SQL, reads them natively, no plugin required. Entity and
relationship data lives in Oxigraph as RDF, queryable over SPARQL.

It feeds from Windrow (BACnet/Modbus → MQTT, a sibling project) over the same
wire envelope both `mqtt_listener.py` and `POST /ingest` consume.

## Where to go next

- **[Architecture](/architecture)** — the real service topology: what
  runs where, what talks to what, and why.
- **[Fault Detection](/fault-detection)** — how `range`/`stuck`/`stale`
  rules work, and the gotchas that aren't obvious from the code.
- **[Webhooks](/webhooks)** — delivery semantics, signing, retries, and
  the one security caveat you need to know before registering one.
- **[Haxall Drop-In](/haxall-drop-in)** — how Baler becomes the
  actual history backend behind a real Haxall project, proven live.
- **[Haystack Puller](/haystack-puller)** — the opposite direction: an
  opt-in daemon that pulls points, equipment, and history from a remote
  Haystack/Haxall/SkySpark server.
- **[Adding a Data Source](/adding-a-data-source)** — which repo a new
  source belongs in, and the pattern to follow either way.
- **[Weather Stations](/weather-stations)** — "add your own" local weather
  station, recorded as points, with no WWW dependency.
- **API Reference** — both APIs, generated live from the same
  `openapi.yaml` / `fault-api-openapi.yaml` files each process serves at
  `GET /openapi.yaml`.