Hello everyone, The issue relates to the Carrier Service API. Our app is responsible for delivering shipping rate calculations based on defined conditions — as described in the App Store: Your shipping, your rules! Offer precise shipping rates tailored to every customer and destination. Create y…

Hi folks, thanks again for your patience while we looked into this, I have some context to share and an update. Right now, this is expected behaviour but it was undocumented. Essentially, the backup rates are being triggered by a connection establishment timeout, which is separate from the respon…

Hey @Alan_G , here is another one 8284108849458. We had no requests reaching our API. Our clients are getting frustrated to see such inconsistencies. Please advise on how we can prevent back rates from showing up.

hey @Alan_G new Order ID: 7072724877649

Hi @Alan_G we’re seeing an uptick of backup rates recently too, but checking our servers, there’s been no change in load or issues from what i can see, it’ll be good if i can get some insight into what shopify sees on their end, any error codes etc. In some instances we don’t receive the request at …

@Alan_G Are you able to provide an update here please? I’m getting more reports of these from merchants, most of the orders we have matching logs on our end which shows our app returned rates without any timeouts, other orders we don’t receive any payloads. It would be good to get to the bottom of t…

Hey @Alan_G , thank you for the details. Are you able to share some logs or timetamps about this connection timeout for our specific orders? What step of the TCP connection was slow (TLS handshake? DNS resolution? ACK reply?…). Our DNS is hosted on AWS, and our carrier is handled by AWS lambdas so…

No worries @Francois_Rulliere - I’ll send you a DM so we can look into this a bit more. I’ll need to grab some potentially more private info, so don’t want to surface that publicly if we can help it! Speak with you that way shortly.

Hi @Alan_G , Thank you for the explanation of the two tiers of timeouts. I’m also experiencing an up-tick in backup rates, recently. I don’t think it’s from a TCP Connection Timeout. Can I kindly ask you to look into this order Id: 7339225120835, which received a backup rate. According to my lo…

Hi @Phil_Sebastian_Coffe , happy to dig into this for you to see exactly where the timeout occurred. Could you share your shop domain, the carrier service endpoint URL that Shopify is calling, and which AWS region your Lambda is deployed in? That’ll help me correlate our connection logs with your i…

Thanks for your prompt reply and the follow-up. I’d rather DM with this info.

No worries @Phil_Sebastian_Coffe - DMing you, thanks again for your patience on this!

Issue with “Backup rates” message in Carrier Service API

Fulfillment & Inventory

Min_Liu March 3, 2026, 5:32am 37

Hi everyone, we’re seeing backup rates being thrown prematurely, the response from Shopify support is pretty alarming and you guys may be interested in this thread: Shopify backup rates triggering prematurely - #2 by Min_Liu

Topic		Replies	Views
Shopify backup rates triggering prematurely GraphQL Admin API Troubleshooting general-gql-troubles	9	284	March 23, 2026
Shipping Rates – Return backup rates for 3xx and 4xx carrier responses Changelog	0	54	May 22, 2025
Carrier service not called when attaching to shipping zone (Admin) – intermittent behavior Fulfillment & Inventory fulfillment-services	7	163	March 10, 2026
Issue with ajax cart API async_shipping_rates.json Online Store and Theme Development ajax-api	17	321	February 6, 2026
Requirements for being compatible with subscription orders Products and Orders APIs admin-api-orders , subscription-api	1	69	August 20, 2025

Issue with “Backup rates” message in Carrier Service API

Related topics