Test the whole journey,
not just the unit.

Your team ships features faster than ever. AI coding tools write the first draft, and a small team now moves like a large one.

Testing did not keep up. The slowest, most fragile layer is the one that checks a whole user journey end to end. It is also the layer that catches the bugs unit tests never see. So it is the first thing teams skip, and the first thing that bites them in production.

Unit tests check a single piece of code. End-to-end tests check what the user actually does. Here is where each layer fits:

A real end-to-end suite covers the journeys that lose you customers when they break:

• Sign-in, SSO, and permissions. Login, logout, role-based access, and the checks that a viewer cannot reach what an admin can.
• Payments, carts, subscriptions, and refunds. The full purchase path, including upgrades, coupon codes, and the refund flow.
• Email and magic-link flows. Passmark receives the verification email, extracts the code, and carries the journey through signup or login the way a real user would.
• Uploads, forms, and error states. File uploads across types and sizes, form validation, and the messages users see when something goes wrong.
• Multi-tenant isolation. A test creates two tenants and confirms one never sees the other’s data.

Traditional E2E tests are scripts tied to selectors. They name the exact button, class, or test id to click. The test passes until a developer renames that element, then it fails even though the feature still works. This is why so many teams have an E2E suite they have stopped trusting.

Bug0 writes the same test as intent, not implementation. The step describes what the user wants. The engine figures out how to do it at run time:

await page.click('[data-testid="submit-btn"]');
await page.waitForSelector('.success-message');

await runSteps([
  { description: "Submit the form" },
  { description: "Verify the success message appears" },
]);

Bug0 is Passmark as a service. Your forward-deployed engineer builds the suite on the engine, and the engine runs and heals it.

• Plain-English steps on Passmark. Each step is resolved into a real Playwright action, with smart waits instead of hardcoded timeouts, so tests are stable without sleep statements.
• Self-healing. When the UI changes, Passmark re-resolves the affected step with fresh AI rather than failing on a dead selector.
• Catches what screenshots miss. Video assertions record the whole step, so a toast or snackbar that flashes for half a second is still verified.
• Fast and verified. Hundreds of browser tests run in parallel in under five minutes, on every pull request, and a forward-deployed engineer verifies every failure before it reaches you.

The real question is not which tool, but who writes and maintains the tests once your app starts changing.

Bug0 end-to-end testing is web browser testing. We cover web applications: B2B SaaS, internal tools, and customer-facing products built on modern frameworks like React, Vue, and Next.js.

We do not test mobile-native apps, API-only flows without a UI, or run load testing. If your product lives in a browser, we cover it end to end. The engine, Passmark, is open source, so there is no lock-in.