Resolving a Translation API Issue Impacting Cypress End-to-End Testing

This article describes a technical challenge encountered during end-to-end (E2E) testing of a multilingual Enterprise Resource Planning (ERP) system using Cypress.io. Despite the application working flawlessly in real browsers, automated tests started failing due to translation labels showing raw keys instead of translated values. The root cause was identified as an ERR_INCOMPLETE_CHUNKED_ENCODING error from the translation API, caused by server-side issues with HTTP chunked encoding and gzip compression. This problem was compounded by 404 errors on static assets due to server configuration inconsistencies when proxied by Cypress, which handles HTTP responses more strictly than browsers. The article emphasizes the importance of cross-team collaboration between QA, backend developers, and DevOps to diagnose such obscure infrastructure problems. Temporarily, the team bypassed the flaky server responses by mocking translation API calls and static assets with local fixtures in Cypress, restoring stability to the test suite. The case illustrates how E2E tests can reveal subtle backend or infrastructure flaws unnoticed during manual testing and underscores the value of understanding Cypress’s proxy behavior and using mocks to maintain automation reliability while awaiting permanent server fixes.