Concepts¶

These pages give you the mental model behind Courier's runtime. They are short by design — read them before writing your own components.

• Envelope — the single message type that flows between every node.
• Backpressure — how bounded channels and the broadcast splitter shape end-to-end flow control.
• Observability — structured logs, metrics, and W3C-propagated traces exported via OTLP.
• Lifecycle, health probes, and shutdown — pipeline states, health endpoints, graceful drain, and exit codes.
• Components — the built-in sources, transforms, sinks, and extension points.