API returns 303 response on Shopify checkout creation

Technical Q&A

Topic summary

API checkout creation calls are returning HTTP 303 (See Other) when made in parallel via restClient.shopifyClient.rest.Checkout(…). The requester asks whether this is a Shopify issue or a client-side mistake.

Key points:

  • 303 indicates a redirection rather than a server error; the request may be getting redirected to another URL.
  • Potential causes: invalid/expired session authentication and hitting rate limits due to concurrent (parallel) requests.
  • Correct API usage should be verified (endpoint and HTTP method) to ensure the call aligns with Shopify’s expectations.

Recommended actions:

  • Validate the session is active and properly authenticated before calling checkout.save().
  • Throttle or serialize concurrent checkout creations to avoid rate limiting.
  • Confirm endpoint/method correctness for the Checkout REST resource.
  • Implement handling for 303 responses (follow redirect or retry logic) as shown in the provided JavaScript example.

Artifacts: A short code snippet demonstrates catching a 303 and handling redirection or retry. No images or attachments.

Status: No definitive root cause confirmed; guidance provided, and the issue remains open pending the requester’s checks.

Summarized with AI on December 28. AI used: gpt-5.
1

Hi, When I am on sending parallel call to a Shopify checkout creation API:
“const checkout = new restClient.shopifyClient.rest.Checkout({session: restClient.session});
checkout.save()”.
I am getting the following response:
“303 If you report this error, please include this id: ec08ca43-7080-442e-9b14-b1356a18826f-1716393386” from Shopify while calling the checkout creation Shopify API

I want to know why I am getting this error or that if it’s an issue from the Shopify side or if it’s something I am missing.

2

The 303 error you’re seeing usually means Shopify is redirecting your request to a different URL. Here are some things to check

  1. Session: Make sure your session is valid and authenticated. If it’s expired you’ll get errors

  2. Too Many Requests: If you’re making many API calls at the same time, you might be hitting Shopify’s rate limits try spacing out your requests

  3. Correct API Usage: Double-check that you’re using the right API endpoint and method

    It should look something like that

const checkout = new restClient.shopifyClient.rest.Checkout({session: restClient.session});

checkout.save()
  .then(response => {
    console.log('Checkout created successfully:', response);
  })
  .catch(error => {
    if (error.status === 303) {
      console.error('Received 303 See Other response:', error.response);
      // Handle redirection or retry here
    } else {
      console.error('Error creating checkout:', error);
    }
  });