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dev_to 2026年3月7日

Chromium拡張機能を使用してAPIレスポンスを即時にシミュレートしました

I Built a Chrome Extension to Simulate API Responses Instantly

Translated: 2026/3/7 11:03:42
google-chromechrome-extensionapi-mockingfrontend-developmentapi-simulation

Japanese Translation

ソフトウェア開発のduring中、フロントエンドはしばしばリモートのバックエンドAPIによって制約を受けます。これはしばしば問題になる点です:待機 API の実装完了に至るまでの待ち時間です。

Original Content

During software development, frontend work often depends on backend APIs that may not always be ready. This creates common challenges: waiting for backend APIs to be implemented testing error responses or edge cases simulating slow network responses verifying UI behavior with different payloads While there are tools available for API mocking, many of them require additional setup such as proxies or backend configuration. I wanted a simpler solution that works directly inside the browser. So I built a browser extension for Google Chrome that allows developers to intercept API requests and return custom responses instantly. What the Extension Does The extension lets developers define rules that match specific API requests. When a request matches a rule, the extension can return a mocked response instead of the original response from the server. This makes it possible to: test frontend features without backend dependencies simulate error responses test different payload structures debug applications faster All of this happens directly in the browser without modifying the application code. Why This Is Useful This approach helps developers: continue development without waiting for backend APIs simulate multiple scenarios quickly test UI behavior under different conditions speed up debugging and testing workflows Full Technical Article I wrote a detailed blog post explaining the architecture, implementation, and examples. You can read the full article here: 👉 Medium Article: https://medium.com/@hritik4november2003/tired-of-waiting-for-backend-apis-i-built-a-chrome-extension-to-simulate-them-31466f42ed52