Changes to CarrierService API rate request timeouts - 10s -> 5s

Shopify Staff
Shopify Staff
57 4 28

UPDATE - Nov 3, 2020:

TL;DR: Shopify will be moving to a dynamic timeout based on the number of requests made per minute.



TL;DR - We will not ship this change. The timeout will remain at 10 seconds.



TL;DR - The timeout for responding to rate requests from Shopify is being lowered to 5s on Wednesday, September 30th.

BFCM 2020 is exceptional. We have already experienced unprecedented traffic levels on our platform and as trusted partners, you certainly have had to scale your infrastructure, and are busy doing BFCM preparations to ensure a smooth and incident-free holiday season. As we continue to prepare for BFCM 2020, Shopify is looking to optimize the overall performance of checkout. A root cause of merchant, partner, and customer dissatisfaction is the dependence on external calls, including usage of the CarrierService API. 

To protect buyers, merchants, partners, and the platform, we're lowering the timeout for CarrierService API rate requests from 10 seconds to 5 seconds.

Dealing with timeouts - Backup rates

We understand that custom rate calculations are complex, and can often depend on even more external factors that are invisible to Shopify. In order to gracefully handle the timeout, and avoid returning no rates at checkout, we recommend you configure your app to return a backup rate when approaching the time limit.

Example Implementation

To prepare for returning a backup rate, we add a new field to our app’s configuration, which captures the backup rate the merchant would like to surface.

During rate calculation, if the total process for a specific rate request is approaching 5 seconds, we refer to our previous field and return that. Alternatively, if our rate calculation provides us with information as it processes, we can return our current best guess.

Both of these will return a less accurate rate than under optimal conditions, but will not timeout, allowing the checkout to complete.


We expect to ship this change to all our rate requests on Wednesday, September 30th.

We encourage you to implement fallback rates and test with our current timeout as part of your BFCM 2020 prep.

Shopify Partner
124 6 24

Hey @Alex_B,

Is there any way to extend the date to give developers a bit more time here? Our average calculation time is 1 second or less for live rates & rules, so in a regular use case this is completely fine. However, we have a significant number of users who use Intuitive Shipping for very complex shipping setups, with a large proportion being Plus stores who require granular control. We've been given 4 days to create a timeout fallback in our apps, add it into our UIs, and to educate our affected users on the new changes and what an effective fallback rate would be in their store. It's simply not enough time to educate and implement this for merchants, especially considering we are entering the weekend. 



Co-Founder / CEO @ Intuitive Shipping Inc.
Intuitive Shipping | Smart Boxing | Automate Shipping Profiles

3 0 4

Echo "We've been given 4 days to create a timeout fallback in our apps, add it into our UIs, and to educate our affected users on the new changes and what an effective fallback rate would be in their store. It's simply not enough time to educate and implement this for merchants, especially considering we are entering the weekend."

Shopify Expert
4476 45 484

Ha. I can almost guarantee that this decision will result in the following.

Any merchants using and depending on Carrier Service requests that are at all complex and take 5001 ms or more to respond will simply die. And when they complain, the complaints will 100% be directed at Shopify. And so it goes. 

There is a puny to approaching zero chance App developers will respond by implementing this quaint little pseudo-pattern as presented. Makes no difference to Plus or non-plus... it is simply hardcore.

As the author of ~20 CustomCarrier Apps of various age, ability and utility, I am pretty sure I am going to just ignore this change, and let the merchants scream at Shopify. Not my gig to jump to the pump for what has never been a problem to date. All the previous BFCM dates in the past came and went with exactly zero complaints. Well, let's see if 2020 is a repeat!

Making popcorn now.




Custom Shopify Apps built just for you!
19 0 10


Could you please reconsider this or consider making the request timeout configurable per shop? Not to mention the lack of notice here is terrible especially that this means many shops would timeout and show nothing for shipping and thus halt checkout without CarrierService developers even being able to show an error message.

Also realistically what is the point of this? Shopify currently retries CarrierService calls 3-4 times if it hits the timeout. You are really telling developers to create some sort of complex rate resumption/order lookup(btw we still don't get a checkout id when rates are requested) in order to get up to `timeout * max retries` to calculate a rate. We haven't had to implement this yet but it doesn't sound fun especially when you have to sync requests from multiple servers.

Our app FreightChick connects 20+ LTL carriers to Shopify and often requires complex 3d bin packing calculations to figure out the final dimensions packages/pallets/etc. Bin packing even with bleeding edge algorithms and methods can take several seconds when there are many items. This means you already only have 3-5 seconds on a bad(400-500+ item) order before you have to cut off any pending rates and just pick from the ones which returned quickly. We do this currently but it'd basically mean for the large orders we'd have almost no time. Also the LTL industry as a whole is well on its way towards only allowing volume/dimensional rates which require 3d bin packing.


We developed the Shopify integration for a Shopify Plus customer who also runs several other shops and we plan to launch our public app soon. You are making it harder and harder to integrate shipping with Shopify. We can't return an error message, get a checkout id, or stream rates as they come back from carriers(1 carrier service limit per app + you'd have to sync all the pre rate calculations like bin packing between multiple requests unless you actually support streamed responses).

FreightChick - Automate your Logistics
CartJumper - Sync with NetSuite
Shopify Partner
9 0 7

You're seriously springing notice of a midweek API change on the preceding Friday afternoon?

Shopify Expert
4476 45 484

That is management for you! Release the new code to production on Friday at 5:00pm! Live large!

I would've approached this by making it opt-out with a simple tick-box. Since Shopify knows if a shop has CarrierServices registered, they could simply offer a checkbox to allow the reduction to 5 second or NOT, especially since for a minority of important customers, that might be a deal breaker!

But alas, I am not in charge, so I sit by and once again marvel at the internal machinations. Simply marvelous!

Custom Shopify Apps built just for you!
Shopify Partner
78 1 35

Hi Shopify,

I think this should be a opt out option as well, as an app that runs thousands of stores, I can tell you now you will have hundreds of merchants left out in the cold and unable the transact, many of them plus customers, you need to consider the fact that some merchants have complex rates and needs to look up several live carrier rates, this often takes over 5seconds.



Shopify Partner
164 9 55

Hey Shopify Shipping Team,

Unfortunately, at this point, we haven't been given enough notice to implement a fallback rates feature as a knee jerk reaction to this last-minute decision.  All we can do now is reach out to the merchants who may be impacted and try to find ways to streamline their setup.

What's confusing is that one of the reasons for making this decision is for the betterment of the merchant.  From experience, merchants who require complicated shipping expect the checkout to be slightly slower.  The trade-off is accurate shipping calculations ensuring they remain profitable at the end of the month.  If this decision was really in the best interest of the merchant, the decision would be left up to the merchant to make.  If an app that they're using for shipping is too slow, they have every reason to switch to a faster app.  This keeps app developers competitive.

This decision, however, will negatively impact merchants because they're not given a say in this process at all.  This is being forced on them and the consequence will be that they're unable to make sales because their shipping solution may not surface rates fast enough.  What tends to be overlooked with changes like this is that not all merchants fit inside a tidy little box.  There are many outliers, and those outliers are the ones most likely to be using carrier services.

We have invested a significant amount of time and resources to streamline our entire rating process, but at the end of the day, we're still at the mercy of external services such as Shopify's Admin API and third-party carriers which consume over 90% of our current calculation times.  If the goal is to reduce latency, we need a better version of carrier services that includes additional information such as customer tags, etc.  This will reduce overhead both on carrier services as well as Shopify's Admin API.

Since we're discussing BFCM, has there been consideration to take into account that BFCM sees a spike in server demand for everyone, including third-party carriers, seeing an increase in their own response time.  This naturally causes our response times to climb which would cause our system to be unable to return rates in time, preventing the end customer from completing checkout and the merchant losing a sale.  This is not a better experience for either merchant or customer.

Ultimately, I believe a better approach would be to educate merchants on checkout speed.  The faster the checkout, the better the customer experience, which results in a higher conversion rate.

Co-Founder / CTO @ Intuitive Shipping Inc.
Intuitive Shipping | Smart Boxing | Automate Shipping Profiles
Shopify Partner
78 1 35

Yes precisely,

FedEx and UPS endpoints have been quite flakey in the past month or so too, I can imagine the spike of users come BFCM will cause merchants that run under the limit now be impacted once this change is out through too. A lot of merchants is already dissatisfied with the level of support of shipping rates in Shopify, this will likely be the final nail in the coffin which forces then to leave Shopify for good, its a lose lose for everyone.

Merchants who are forced to simplify their rates will likely lose money on shipping too, or lose customers if their rates aren't competitive enough, multiply this by volume there are significant losses here.

There is lots that can be done to improve the carrier service API so these requests can be made more efficient too, however there has been absolutely no improvement in at least the past 7 years, It would be a much better approach to give us the right tools first before taking away the capabilities.