Is there any way to make Shopify CLI spit out the final file that will be used for file size validations
Not at this time, but the feedback is noted.
I built this for myself: https://compress.r10r.dev/ (It’s not an official tool, but maybe it can help)
new checkout file
Original: 21.14 KB
Gzip: 8.22 KB (61.1% smaller)
Brotli: 7.49 KB (64.6% smaller)
@muchisx the nightly version of the cli now contains a change that will show the original and uncompressed size of UI extensions when you run app build or app dev.
ext-1 │ ext-1 successfully built (25.5 KB original, ~9.7 KB compressed)
ext-2 │ ext-2 successfully built (118.3 KB original, ~37.3 KB compressed)
The change should land in the next stable version of the CLI in a couple of weeks.
Since it’s only in nightly, I suggest that if you want to try it, don’t do it on your production app!
Thanks for the update on that front, that will be certainly extremely helpful !
On the proposed limit front, is there any chance on discussion for the possibility of grandfathering existing apps to the existing limit or/and to increase the global proposed limit?
Hey, I brought this feedback to the team and it’s being discussed internally. For now there are no plans to change extension file size limits.
Hi @Robin-Shopify,
I appreciate the update, and was curious if there has been anything new from the team with regards to this issue?
I’ve just finished a build of migrating my checkout-extensions from API version 2025-07 to 2025-10 which includes the preact migration along with the new 64kb bundle size limit, and though my bundle size decreased quite a bit from ~500kb to now ~380kb (~80 KB gzipped as per Shopify CLI) it still doesn’t meet the new 64kb requirement.
Going forward I think my only option is to split major features into separate smaller extensions in order to meet the size limit. However this creates some problems that I’m not sure how to proceed with.
If I move forward with the migration and split up my extension into several smaller ones then deploying this change will cause breaking changes to many store checkouts because features present in the old extension would have to be removed and added to a new and separate extension that they would need to manually add to their checkout.
I can reach out to the merchants ahead of time to help with migration but there’s a good chance many will not respond or miss the email, so they would not know until they find out their customized checkout flow is not working as intended.
If I ignore the changes then my existing merchants continue without interruption, but come 2026-10 and pushing any updates to my app or any of its other functions will no longer be possible due to the enforced 64kb limit. I’m not sure what happens after 2025-07 is no longer supported either, but I think this essentially means my app dies.
It just seems like there’s no smooth path forward for apps that are above the current 64kb limit trying to migrate, at least not without high risk of breaking existing checkout customizations.
But if older apps were grandfathered in with a higher limit similar to what is being done with the new Metafields 16KB limit, or if the limit was raised, it would help a lot with the migration. Otherwise I’m not sure how best to proceed or if there’s any other alternatives I’m missing.
Could you update us on Shopify’s stance on this? If I understand correctly, deprecation starts next month (2026-07), we’ve done plenty of prototypes for migrating but they all require breaking changes to our features and will interrupt merchant’s setups.
Sadly our extension can’t be just simply split into multiple extensions, so with this change it would basically break it.