Plugin Overview

Add cross-cutting behavior without coupling your application to a provider.

Plugins are optional packages that extend Postbote at three distinct points.

Plugin	Capability	Use it for
`hooks()`	Middleware	Policy checks, message changes, lifecycle callbacks
`failover()`	Middleware	Switching to fallback adapters
`rateLimit()`	Middleware	Client-side throttling before a provider returns 429
`dryRun()`	Middleware	Staging and CI sends without calling an adapter
`redirect()`	Middleware	Replacing real recipients in staging
`logger()`	Middleware	JSON-safe lifecycle events
`otel()`	Middleware	OpenTelemetry spans and attempt events
`reactEmail()`	Input transform	Rendering a `ReactElement` to HTML and text
`betterResult()`	Send wrapper	Returning `Result` instead of rejecting

All plugins are explicit. Install only the capability you need and keep them in a tuple when their type extension matters.

src/lib/mailer.ts

const plugins = [reactEmail(), betterResult()] as const;
const mailer = createPostbote({ adapter, plugins });