How to Seed a Real Backend for Playwright E2E Tests Using Batch APIs

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End-to-end test suites in Playwright commonly fail due to three data management problems: UI-driven setup, shared mutable databases, and hand-maintained fixture files. Each approach introduces fragility — slow test runs, order-dependent failures, or silent schema mismatches. A more reliable pattern involves describing required database records as templates with a fixed seed value, then generating them via a batch API before any test runs. Playwright's globalSetup hook can call this API, insert the results into a test database, and write the output to a local JSON fixture file. Individual spec files then import that fixture directly, eliminating redundant setup logic and making test data consistent and reproducible across environments.

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