Building an app with AI tools is fast. Keeping it working after every update is the hard part, because one small change can break a screen you never touched. TestGrid's CoTester is an AI testing agent that writes and runs tests for web and mobile apps. Here is what it does, what it costs, and a test brief you can paste in on day one.
What you need
TestGrid CoTester: testgrid.io/cotester. Paid. The Starter package is listed at $199 per seat per month, with 4 devices or browsers and 5,000 tokens. Larger plans are custom-priced. See testgrid.io/pricing.
A trial or demo: You can request a free trial or book a demo. The pricing page FAQ says TestGrid usually offers a guided proof-of-concept of one to two weeks rather than a self-serve free trial.
Your app: A live or staging URL for a website, or a build of your mobile app.
Optional: Your Jira stories or a written spec, which CoTester can turn into tests.
Step by step
1. Sign up and set up your project. Request the trial, then add your app's URL or mobile build when your account is ready.
2. Pick your most important flows. Do not try to test everything at once. Choose the 3 to 5 journeys that would cost you users or money if they broke, such as sign-up, login, checkout or the main feature.
3. Describe the tests in plain language. TestGrid says CoTester can create test logic from a pasted URL, an uploaded document, or a plain-language description. Fill in the brackets and paste this:
App URL: [your staging URL]
Test these user journeys on Chrome desktop and one Android phone:
1. Sign up: open the home page, click "Sign up", enter a new email and a valid password, submit, and confirm the user lands on the dashboard and sees a welcome message.
2. Login and logout: log in with the test account [email / password], confirm the dashboard loads, log out, and confirm the user is back on the login page.
3. Wrong password: try to log in with a wrong password and confirm a clear error message appears and the user is not logged in.
4. Main feature: [describe the one action your app exists for, step by step, and what the user should see at the end].
5. Payment or form submit: [describe the steps], using test data only, and confirm the success screen appears.
For every failed step, record a screenshot, the step that failed, what was expected and what actually happened.4. Review before you run. TestGrid says the agent pauses at checkpoints and does not run anything without your approval. Read the generated steps and fix anything it misunderstood.
5. Run and read the report. After a run you get execution logs and screenshots, and the agent flags bugs it finds. Check each failure yourself before you treat it as a real bug.
6. Schedule regular runs. You can schedule runs for nightly builds, weekly regressions or before each release. A good habit is to run your core flows after every update you ship.
7. Keep a manual checklist too. Use this short list before each release, whatever tool you use:
Pre-release checklist
[ ] Sign up, login, logout and password reset all work
[ ] Main feature works end to end with real-looking data
[ ] Forms show clear errors for empty and wrong inputs
[ ] Payments work in test mode and show the right amount
[ ] Pages load and look right on a small phone screen
[ ] Nothing broke on screens you did not change
[ ] No test data or debug messages visible to usersGood to know
The big claims are TestGrid's own. TestGrid says its "AgentRx" auto-heal engine detects UI changes, including redesigns, and updates tests while they run, and that a vision-language model reads screens using visuals, text and layout. We could not find independent tests of how well this works.
It is built for teams. TestGrid pitches CoTester at banking, e-commerce, telecom, healthcare and travel companies. At $199 per seat per month, it may be more than a solo builder needs.
Privacy. Use test accounts and test payment modes, not real customer data. TestGrid says it supports private cloud and on-premise setups for stricter needs.
No tool catches everything. Automated tests only check what you describe. Keep testing new features by hand too.
Sources
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