Playwright Test Data: Seeding a Real Backend for E2E Suites

Playwright test data is the set of database rows or API records your application needs to already contain before a browser test runs against it — a logged-in user, their orders, the products those orders reference — generated deterministically so the same run produces the same data every time. Unlike unit tests, a Playwright (or Cypress) spec drives a real browser against a real, running app, which means the backend behind it needs real rows to serve, not an intercepted network response. Getting that data right, and getting it there before the first test starts, is most of what makes a browser E2E suite fast and non-flaky instead of slow and order-dependent. Why is E2E test data hard to manage? Three patterns keep showing up, and each causes a different failure mode: Tests create their own data through the UI. A test that needs an order to exist first signs up a user, logs in, adds a product to a cart, and checks out — all before the actual assertion it cares about. That's slow multiplied across every spec that needs similar setup, and it means the thing under test (the UI) is also the thing doing the setup, so a bug in signup breaks fifty unrelated tests. A shared, mutable test database. If every spec reads and writes the same rows, test order starts to matter: a test that deletes a user breaks a later test that assumed that user still exists. This is one of the most common sources of a suite that passes locally, one file at a time, and fails intermittently in CI when specs run in parallel or in a different order. Hand-maintained fixture SQL or JSON. A fixtures.sql file or a static users.json works until the schema changes — a column gets renamed, a new required field is added — and the fixture silently stops matching what the app expects, or starts failing inserts with no clear signal about which of forty rows is the problem. The fix for all three is the same shape: generate the data the suite needs from a definition (a template), with a fixed seed, right before t