The Now Shipping API enforces a rate limit of 120 requests per minute per API key. This limit applies across all endpoints and all merchants served by the same key. If your integration exceeds the limit, the API stops processing requests until the window resets and returns HTTP 429 for every subsequent call until then.
Rate limit details
Error response
When you exceed the rate limit, every request returns the following response until the window resets:
Do not retry a 429 response immediately. Retrying without a delay will keep your integration locked out for the remainder of the current window and can cause your requests to pile up, making the problem worse.
Best practices
Implement exponential backoff
When you receive a 429, wait before retrying. Use exponential backoff with jitter so multiple workers in your system don’t all retry at the same instant:
A simple backoff strategy: wait min(2^attempt × 100ms + random(0–100ms), 30s) before each retry. Cap retries at 5 attempts and surface a meaningful error to your system if all retries are exhausted.
Cache the zone catalog
GET /delivery-zones returns an ETag header. Store the ETag and send it as If-None-Match on subsequent requests. When the catalog hasn’t changed, the API returns 304 Not Modified with no body — this response still counts against your limit but transfers no data and is processed faster.
Avoid polling order status in tight loops
If you need to track order status changes, use a reasonable polling interval (for example, every 2–5 minutes) rather than polling continuously. Tight polling loops are one of the most common causes of hitting the rate limit unnecessarily.
Space out bulk operations
If your integration creates many orders in a batch — for example, processing overnight orders in the morning — distribute those requests over time rather than firing them all at once. At 120 requests per minute, you can safely sustain one request every 500 ms with comfortable headroom.
Requesting a higher rate limit
If your integration legitimately requires more than 120 requests per minute — for example, during peak sales periods or high-volume batch processing — contact your Now Shipping account manager. Rate limit increases are evaluated on a case-by-case basis. 