Online Fiddler Alternatives
Fiddler is not available as a web app but there are some alternatives that runs in the browser with similar functionality. The best Online alternative is HTTP Toolkit, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 25 alternatives to Fiddler and six of them are available as a web app so hopefully you can find a suitable replacement. Other interesting Online alternatives to Fiddler are StopLight (Free Personal), RestCase (Freemium), CYFIRMA CAP (Freemium) and HTTP Header Live (Free, Open Source).