# Verify Then Control The Data

DevFeed: [Verify Then Control The Data](<https://devfeed.tech/articles/verify-then-control-the-data-28903.md>)

Original publisher: [Read original article](<https://glebbahmutov.com/blog/verify-then-control-the-data/>)

Author: Gleb Bahmutov

Published: 2025-11-30T05:00:00Z

Content type: tutorial

Language: en

Sources: [Gleb Bahmutov](<https://devfeed.tech/sources/gleb-bahmutov.md>)

Topics: [Testing](<https://devfeed.tech/topics/testing.md>), [Cypress](<https://devfeed.tech/topics/cypress.md>), [Web](<https://devfeed.tech/topics/web.md>), [API](<https://devfeed.tech/topics/api.md>)

Tags: [advice](<https://devfeed.tech/tags/advice.md>), [api](<https://devfeed.tech/tags/api.md>), [cypress](<https://devfeed.tech/tags/cypress.md>), [json](<https://devfeed.tech/tags/json.md>), [network-testing](<https://devfeed.tech/tags/network-testing.md>), [process](<https://devfeed.tech/tags/process.md>), [schema](<https://devfeed.tech/tags/schema.md>), [testing](<https://devfeed.tech/tags/testing.md>), [verify](<https://devfeed.tech/tags/verify.md>), [web](<https://devfeed.tech/tags/web.md>)

## AI overview

This tutorial presents four ways to test a web page that receives two numbers from a server and displays their sum. It recommends validating the server response against an expected schema, then stubbing the network response with deterministic mock data and checking the page's result.

## Source excerpt

Imagine we are testing a web page that receives two numbers from the server and then shows their sum