Hi everyone,
We’re happy to share that nested modifier support in the Catalog API shipped as part of the 2026-08-19 API release.
What’s changed:
Nested modifiers are now available in the public API. Previously, access required being added to an Alpha feature flag — that’s no longer the case. Any integrator can now read and edit nested modifiers.
How to get access:
Upgrade your API version to 2026-08-19 or later. That’s it — no allowlisting or feature flag request needed.
Documentation:
We’ve published a developer guide to walk you through the feature:
If you run into issues or have questions about integrating, reply in this thread and we’ll help out.
How would the nested modifiers show up in the older versions of the Square API?
On API versions earlier than 2026-08-19, nested modifiers
simply aren’t visible - Square omits child_modifier_list_ids from
responses, so you won’t get an error, the field just isn’t there. The same
applies to include_options, which older versions don’t support.
Your existing data is safe. Because the field is omitted from your
responses, a normal read-modify-write cycle sends the object back without
it, and Square treats that as “not supplied” rather than “set to empty” -
your stored nesting carries forward. And if you do try to send
child_modifier_list_ids on an older version, you’ll get a clear 400 rather
than a silent no-op.
In practice this means an older-version integration keeps working exactly as
it does today. You’ll still retrieve all your modifier lists, they’ll just
look flat, with no indication of which list sits beneath which modifier.
Upgrading to 2026-08-19 or later is all that’s needed to see the
relationships.
Let me know if you have a specific scenario in mind and I’m happy to dig in!