Skip to main content

Rate limiting / backoff

Use case​

Respect API rate limits by detecting 429 responses and backing off before retrying.

Interceptor recipe​

import { createClient, isHttpError } from '@parcely/core'

const http = createClient({ baseURL: 'https://api.example.com' })

http.interceptors.response.use(undefined, async (err) => {
  if (!isHttpError(err) || err.status !== 429) throw err

  const retryAfter = err.response?.headers.get('retry-after')
  const delay = retryAfter
    ? parseInt(retryAfter, 10) * 1000
    : 5000 // fallback: 5 seconds

  if (Number.isNaN(delay) || delay > 60000) throw err // don't wait more than 60s

  await new Promise((resolve) => setTimeout(resolve, delay))
  return http.request(err.config)
})

Notes​

  • The Retry-After header may be in seconds or a date string. This example handles the seconds case.
  • Set an upper bound on the retry delay to avoid hanging indefinitely.
  • Combine with the retries with backoff pattern for comprehensive retry logic.
  • A dedicated @parcely/retry package is planned for the future.