Backend function trigger throws internal runtime error

💬 App Building
2

Summary

On the new app builder (Cloud), calling .trigger(...).result on a generated backend-function hook (useBackendFunctions.ts) intermittently throws TypeError: (void 0) is not a function with a stack trace resolving into Retool's own compiled bundle, alongside related reliability issues — the generated hooks file being wiped after saving/publishing, stale 'previous version of this function' run history, and a Cloudflare 502 on a long-running backend function call that actually succeeded server-side.

AI Response

This behavior lines up with recently reported reliability issues in the new app builder's backend functions rather than app code. Retool published an incident on July 14, 2026 in which apps built in the new AI app builder showed an empty Data tab ("This app does not contain any functions") and could not publish because backend functions were flagged as unapproved or not visible — matching the symptom of the generated hooks file being wiped after save/publish; that incident is marked resolved. The pattern of regenerated code stranding or losing uncommitted edits in the new app builder is also independently corroborated in the community. For the long-running call, a Cloudflare 502 after 15–20+ seconds while the work completes server-side is consistent with a gateway timeout on the response rather than a failure of the function itself, so guarding against duplicate side effects and re-checking state after such calls is prudent. Note that the specific (void 0) is not a function runtime error thrown from Retool's own bundle does not have a directly matching public report or documented fix, so that exact signature remains unconfirmed.

Sources

:bookmark: https://status.retool.com
Retool's July 14, 2026 (resolved) incident — new app builder apps showing an empty Data tab and unable to publish because backend functions were unapproved/not visible — directly corroborates the disappearing/wiped generated functions symptom.
:bookmark: On New App Builder: Builder thread strands uncommitted edits — can't publish
A new app builder report of regenerated builder threads stranding uncommitted edits and blocking publish, corroborating the lost/regenerated backend function code reliability issue.

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