Plugins & interceptors

Built-in plugins

Plugin	Role
trace	Adds x-request-id
ssr-forward	Forwards cookies / auth on the server
retry-idempotent	Retries safe methods on retryable statuses
sse-resume	Drops heartbeats; sends Last-Event-ID on reconnect

createFetch({
  plugins: ['trace', 'ssr-forward', 'retry-idempotent', 'sse-resume'],
})

Named interceptors

api.use('locale', {
  order: 25,
  onRequest: (context) => {
    context.request.headers.set('accept-language', 'fa')
    return { action: 'continue', context }
  },
})

api.eject('locale')

Per-request control

await api.get('/admin', {
  interceptors: {
    use: [extraInterceptor],
    eject: ['retry-idempotent'],
  },
})

Match filters

Interceptors can match on operation, method, pathPrefix, or status.

Decision actions: continue · skip · retry · short-circuit · drop.

See Refresh token recipe for a real 401 → refresh → retry interceptor.