Watching network traffic is standard practice on real Playwright teams. You cannot run it in the editor on this site, because our browser engine does not implement request interception. Everything below is real, working Playwright. Use it on a local project and it behaves exactly as described.
Here is a bug that a normal test will never catch.
You create a contact named Dana Fox at the company FoxLabs. The green message appears. The new row appears in the table. Everything looks correct on screen.
But the app sent an empty company name to the server. Nobody notices until a customer opens the record next week.