Stripe API Errors: How to Fix Rate Limits (429), Authentication (401), and Webhook Failures

Understanding the Error

When integrating with the Stripe API, developers frequently encounter HTTP status codes that indicate issues with request volume, authentication, or asynchronous event delivery (webhooks). The most common errors include 429 Too Many Requests (Rate Limit), 401 Unauthorized (Authentication Failed), and various webhook delivery failures.

429 Too Many Requests (Rate Limits)

Stripe limits the number of API requests you can make per second to ensure system stability. For most endpoints in live mode, the limit is 100 read/write operations per second. In test mode, limits are lower (typically 25/second). When you exceed these limits, Stripe returns a 429 status code.

Error Message:

{
  "error": {
    "message": "Rate limit exceeded",
    "type": "invalid_request_error"
  }
}

401 Unauthorized (Authentication Failed)

A 401 error occurs when your API request lacks valid authentication credentials. This typically happens if the API key is missing, malformed, revoked, or if you are using a test key to access live data (or vice versa).

Error Message:

{
  "error": {
    "message": "Invalid API Key provided: sk_test_********************1234",
    "type": "invalid_request_error"
  }
}

Webhook Failures and Timeouts

Stripe uses webhooks to notify your application of asynchronous events (like a successful payment). If your webhook endpoint takes too long to respond, returns a non-2xx status code, or throws an unhandled exception, Stripe considers the delivery a failure and will retry it (for up to 3 days in live mode).

Step 1: Diagnose

1. Check Stripe Dashboard Logs: Navigate to the Developers > Logs section in your Stripe Dashboard. Filter by status codes (429, 401, 500) to identify the specific endpoints and times when errors occurred.
2. Verify API Keys: Ensure your application is loading the correct STRIPE_SECRET_KEY for the current environment. A common mistake is deploying test keys to production.
3. Analyze Webhook Delivery: Check Developers > Webhooks in the dashboard. Look at the "Failed" tab to see the exact HTTP response your server returned to Stripe.

Step 2: Fix

Fixing 429 Rate Limits

The standard solution for rate limiting is implementing Exponential Backoff. Most official Stripe SDKs have built-in support for auto-retries. You can configure this when initializing the client.

Example (Node.js):

const stripe = require('stripe')('sk_test_...', {
  maxNetworkRetries: 3, // Automatically retries requests with exponential backoff
});

If you are writing custom HTTP requests, you must catch the 429 status and retry after a delay that increases exponentially with each failure, adding jitter to prevent thundering herd problems.

Fixing 401 Authentication Errors

1. Double-check your .env file or environment variables in your hosting provider (Vercel, AWS, Heroku).
2. Ensure there are no trailing spaces in the API key string.
3. If a key was compromised and rolled, update your configuration immediately and restart your application.

Fixing Webhook Failures

1. Acknowledge Immediately: Your webhook endpoint should immediately return a 200 OK response before performing any heavy processing (like updating a database or sending emails). Use background jobs (e.g., Celery, Sidekiq, BullMQ) for processing.
2. Verify Signatures: Always verify the Stripe-Signature header to ensure the request actually came from Stripe and wasn't tampered with. If signature verification fails, it will often result in a 400 or 401 on your end.

Example (Express.js Webhook Signature Verification):

app.post('/webhook', express.raw({type: 'application/json'}), (request, response) => {
  const sig = request.headers['stripe-signature'];
  let event;
  try {
    event = stripe.webhooks.constructEvent(request.body, sig, endpointSecret);
  } catch (err) {
    response.status(400).send(`Webhook Error: ${err.message}`);
    return;
  }
  // Handle event...
  response.send(); // Return 200 immediately
});