Looking for a Fiddler alternative?

HTTP Toolkit is a modern powerful alternative to Fiddler designed from the ground up for instant targeted debugging and control of any HTTP(S) traffic.

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One-click setup integrations for every tool you use

HTTP Toolkit includes one-click automated setup to provide precisely targeted interception of individual mobile apps, browsers, terminal windows, Docker containers & more.

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HTTP Toolkit has all the core Fiddler features you use, plus:

One-click zero-configuration HTTPS interception

Inspect & rewrite any HTTPS in seconds, with no global CA certificate required, for mobile apps, browsers, Docker containers, and more.

Built-in documentation

Documentation for every standard HTTP header and status code, plus specific endpoint docs & validation for 2600+ popular APIs, from Stripe to GitHub to AWS.

Powerful rules engine for rewriting & mocking HTTP traffic

Define custom rules that precisely match requests to automatically edit their contents, redirect them, simulate network errors, or breakpoint them for manual modification.

Precisely targeted interception

Capture traffic from an individual browser window, terminal session, or mobile app, without interfering with (or having to filter though) traffic from the rest of your machine.

Extensible & automatable

100% open-source, with interception internals you can integrate directly into your own code to write automated tests or build custom proxies, all available as an Apache-licensed open-source libraryopens in a new tab (that's $0 vs the $2,999/year price tagopens in a new tab to build on FiddlerCore).

Export intercepted traffic as ready-to-use code

One-click export of any collected requests as ready-to-use code for 20+ programming languages & tools.

Capture

Intercept HTTP with zero setup

Capture HTTP(S) with zero hassle, with one-click interception for a huge range of tools and platforms.
Precisely target interception, to capture traffic from a single client without the noise & disruption of intercepting your entire computer.
Intercept individual Android or iOS apps, entire devices, Docker containers, browser windows, backend processes like Node.js, Java, Python or Ruby, terminal sessions...
Alternatively, just connect any client manually to HTTP Toolkit as an HTTP proxy, fully compatible with HTTP requests from anywhere.

inspect

Explore, search & examine HTTP

Hunt through traffic quickly & effectively, with content-type and source categorization, plus powerful filtering tools to precisely match the messages that matter.
Examine the URL, status, headers & body of each message, with built-in parsing of parameters, and explanations & docs from MDN for all standard headers.
Dig into message bodies with highlighting & autoformatting for JSON, Protobuf, Base64, HTML, XML, JS, hex and more, all built on top of Monaco - the editing tools from Visual Studio Code.

breakpoint

Pause & edit live HTTP traffic

Use breakpoints to pause in-flight HTTP traffic for manual editing.
Configure fine-grained matching logic to jump to exactly the cases you care about.
Redirect requests to another URL, update the method, headers or status, or edit the body.
Or get more involved and respond to requests without forwarding them, or even just hard-close connections directly.

Send

Send your own custom requests

Send your own requests directly, to explore APIs or test out different request parameters.
Use the fully featured HTTP client to define every aspect of your request, with automatic handling of details like body compression and message framing.
Explore sent requests & their responses with all the tools & power HTTP Toolkit offers for debugging intercepted traffic.

Modify

Pro Feature

Test with fully automated rewrite rules

Inject mock responses for prototyping and testing

Precisely match interesting requests, then define your own static response or map local files, to test clients against any endpoint behaviour you can imagine. Use it to override real responses, or even to simulate responses from endpoints or entire servers that don't exist yet.

Build, curate & share rulesets

Create rules in one click from intercepted traffic, tune to perfection, then use rule groups & custom aliases to quickly organize rules and toggle behaviours. Once they're perfect, export rules to share with your team or store as your own private library.

Transform, redirect & inject errors

Redirect production sites to local test servers, or block requests with connection resets, timeouts & failing status codes. Want a real response from a target server, but different? Dynamically transform requests or response to inject headers (goodbye CORS errors), match/replace body content, patch JSON bodies, and more.

TESTIMONIALS

Join 667,114 developers

Why HTTP Toolkit?

Numbers that speak for themselves:

years of development

users around the world

open-source contributors

GitHub stars across httptoolkit's repos