Working solution that replaces private apps url proxies?

Topic summary

Main issue: Private apps no longer support app proxies (used to route requests through a shop domain to avoid CORS, e.g., posting form data to an external endpoint). The OP needs a way to embed custom forms that can tag/edit customers and integrate with external systems.

Earlier resolution: Create a public app (unpublished) and use its app proxy. Clarification provided on app types:

  • Private app: single-shop, no OAuth, no proxies/extensions.
  • Public app: installable on multiple shops via OAuth; supports extensions and app proxies. Can be published (App Store) or unpublished (not listed).

New developments and concerns:

  • Shopify is steering developers toward Custom Apps over Private Apps; it’s unclear if Custom Apps support app proxies (question raised, no definitive answer in thread).
  • A participant notes Shopify ended unpublished apps and indicates the unpublished-app workaround may end by 2024-05-05, implying apps must be approved even if not listed; apps must meet general app requirements.
  • Recent breakage reported: POST requests to app proxy endpoints now returning “Bad Request,” previously worked, cause unknown.

Status: Originally marked solved via unpublished public app, but policy changes may invalidate that approach. Open questions: app proxy availability for Custom Apps and reasons for recent proxy POST failures.

Summarized with AI on December 22. AI used: gpt-5.

By any chance is this why my post requests to my app proxy url are suddenly failing now..? Last year my ajax calls to handle moving form submission data form shopify client to my external backend was working smoothly.. now they’ve all been throwing Bad Request errors and I have been trying to resolve this for almost a month now.. does anybody know what changed???