About Fiddler
Fiddler is a web debugging proxy from Progress Telerik. It sits between an application or browser and the network so developers can capture HTTP and HTTPS traffic, inspect requests and responses, mock them and modify them while troubleshooting problems.
The family has several editions: Fiddler Everywhere, a cross-platform application; Fiddler Classic; Fiddler Everywhere Reporter; and FiddlerCore, an embeddable library. Telerik also lists a Fiddler MCP offering among its AI tools. Documentation and support are published separately for each product. Fiddler is proprietary software, and the pricing pages list Fiddler Everywhere and FiddlerCore. It is part of the wider Telerik range of developer tools alongside its UI component bundles.
Key features
- Capture of HTTP and HTTPS traffic
- Inspection of requests and responses
- Mocking and modification of traffic
- Fiddler Everywhere cross-platform app
- FiddlerCore library for embedding
- Fiddler MCP for AI tools
Good fit for
- →Debugging API calls from web and desktop apps
- →Reproducing server responses with mocks
- Tags
- debugging-proxy
- http-debugging
- api-debugging
- telerik
- traffic-capture
- mocking
- desktop-app
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