how to get response in checkout ui extension from third party API without CORS issue

Shopify Apps
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Topic summary

  • Issue: The poster needs to call a third‑party API on Shopify’s Thank You (post‑purchase) page using a Checkout UI extension but consistently encounters CORS (Cross‑Origin Resource Sharing) errors.

  • Goal: Retrieve and display the API response within the post‑purchase experience without violating browser cross‑origin restrictions.

  • Technical note: CORS is a browser security policy that blocks requests to different origins unless the target server returns permissive CORS headers (e.g., Access‑Control‑Allow‑Origin).

  • Status: The author has tried multiple approaches but none worked; they are requesting guidance. No solutions, decisions, or consensus have been provided yet; the question remains open.

Summarized with AI on December 13. AI used: gpt-5.
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I want to get response form a third party API in a thankyou page in shopify using Post purchase chekcout Ui extension, How can i get this without getting CORS headers error. I have tried several option nothing works, can anybody guide me on this