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Offline HTTP Debugger, No Subscription

Complete HTTP Visibility.
Every Layer. Every Byte.

Fluxzy intercepts traffic at the protocol level — HTTP/1.1, HTTP/2, WebSocket — with full header inspection, body decoding, and timing analysis. Forensic-grade capture for production-grade debugging.

All platforms | CLI | Docker | GitHub
Fluxzy Desktop Overview

Explore Features

Comprehensive Rules

Rewrite reality. 50+ actions, mock responses, spoof DNS, throttle bandwidth, fake auth. Edit visually or dive into YAML.

Launch Applications

Skip the system proxy dance. Launch Chrome, Firefox, or any app directly, already hooked and ready to intercept. Zero config.

Live Debugging

Pause traffic at any stage, DNS lookup, before request, after headers. Step through the network like stepping through code.

Capture OS Traffic

One click, and Fluxzy becomes your system proxy. Every HTTP request from every app flows through, no manual browser config needed.

With Raw Capture

PCAP recording is live. Every packet gets saved, not just HTTP, the whole conversation. Wireshark-ready, no extra tools.

Search Everywhere

Ctrl+T your way through Fluxzy. Jump to filters, rules, settings, exchanges, anything. Type what you need and you're there.

Filter Toolbar

Find anything, fast. Ctrl+click to stack filters with AND, Shift+click for OR. Ctrl+Shift live debugs the next matching request. Create and save filter.

Enhanced Response Viewer

Full Monaco editor for your response body. Syntax highlighting, code folding, search, the same editor powering VS Code.

Diff tool

Select two exchanges, hit diff. Headers, body, cookies—everything side by side, changes highlighted. Find what broke between "it worked yesterday" and "it's broken now" in seconds.

Fluxzy Desktop Overview

A Fully-Featured HTTP Debugger

Built with an open-source HTTP engine for maximum transparency and extensibility

Simply Exhaustive

Captures everything from PCAPNG with SSLKEYLOG to deciphered HTTP1.1/H2/Websocket exchanges.

Any Platform

Runs on Windows, macOS, linux and collects traffic for any remote devices including iOS and Android.

Full debugging capabilities

Halt, edit, resubmit, replay, mock, redirect, spoof, ... Fluxzy has everything you expect from an HTTP debugger.

Built for observability

Fast throughput, always streaming by design, every processing block of fluxzy engine has been created to produce minimal overhead.

Codeless traffic alteration

Express simple and declarative directives with YAML files and let Fluxzy connect them to the 100+ built-in filters, actions, and rules.

Live capture

Deflect OS trafic directly to fluxzy or run and hook existing browsers and terminals. Supported environments are Windows, macOS and Gnome based application.

View All Features

Fluxzy Desktop

A modern and intuitive HTTP debugger to enhance your debugging workflow

  • Simplified setup: download, install and run to get started.
  • Easy adoption with the Search everywhere block: reach rapidly most features with a few keystrokes.
  • Choose and combine filters with few clicks and keystrokes.
  • Deflect OS traffic or run and hook browsers and terminals.
Simple and modern UI
  • Hold in the same archive file application and transport layer information.
  • View and extract PCAPNG capture data related to a specific HTTP exchange without noise.
  • Enable NSS key logs capture to view raw packets data in clear. Keys logs are directly embedded into the PCAPNG file.
Capture with raw network packets
  • Activate complex traffic transformation and management through with few clicks
  • Rules can be created, edited and saved through UI and exported to yaml directives for Fluxzy CLI and Fluxzy Core interoperability.
  • 100+ built-in filters and actions to accelerate to fulfill your need. You can browse available rule on this website.
Powerful traffic transformation and management
  • Toggle breakpoints: before establishing a transport connection to the remote, before sending the request and after receiving the response from remote.
  • Inspect and edit any field of the header or the body of the request, response. Change any transport settings: destination authority address and port, supported SSL protocols ..
Live edit

Get a complete and unlimited version of Fluxzy Desktop Community Edition — free forever, no credit card required.

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Ready-to-Use Alteration Directives

Shape web streams in a simple, straightforward, and declarative way

Add, remove, modify any header. Change path, method and request payload.
update-user-agent.yaml 
rules:
  - filter: 
      typeKind: AnyFilter        
    action : 
      typeKind: UpdateRequestHeaderAction
      headerName: user-agent
      # previous reference the original value of the user-agent header
      headerValue: "{{previous}} - Relayed by fluxzy"
Run: fluxzy start -r update-user-agent.yaml
Take advantage of common alteration combination to apply complex transformation.
remove-cache-command.yaml 
rules:
  - filter: 
      typeKind: HostFilter
      pattern: google.com
      operation: endsWith
    action : 
      # This action remove any cache directive from request and response header
      typeKind: RemoveCacheAction
Run: fluxzy start -r remove-cache-command.yaml
Add comments and tags to identify quickly special exchanges.
set-comment-command.yaml 
rules:
  - filter: 
      typeKind: HostFilter
      pattern: google.com
      operation: endsWith
    actions: 
      # Add a comment to any exchange to google.com
      - typeKind: ApplyCommentAction
        comment: Hello fluxzy
Run: fluxzy start -r set-comment-command.yaml
Fluxzy is not narrowed to HTTP level. Use transport level directives to alter IP resolution, simulate connection failures, restrict SSL protocols, ...
client-certificate.yaml 
rules:
    - filter: 
        typeKind: HostFilter
        pattern: mtls.domain.com
    - action: 
        typeKind: SetClientCertificateAction
        clientCertificate: 
        pkcs12File: certificate.pfx
        # password is taken from environment variable CERT_PASSWORD
        pkcs12Password: ${env.CERT_PASSWORD} 
        retrieveMode: FromPkcs12
Run: fluxzy start -r client-certificate.yaml
Capture contextual datas and reuse it in other directive.
capture-bearer-token.yaml 
rules:
  - filter: 
      typeKind: FilterCollection # can be multiple combination of filters
      operation: and
      children:
         - typeKind: postFilter # select only post requests 
         - typeKind: requestHeaderFilter
           headerName: authorization # select only request with authorization header
           operation: regex
           pattern: "Bearer (?<BEARER_TOKEN>.*)" # A named regex instructs fluxzy
                                                 # to extract token from authorization
                                                 # header into the variable BEARER_TOKEN
    action : 
      # Write the token on file 
      typeKind: FileAppendAction # Append the token to the file
      filename: token-file.txt # save the token to token-file.txt
      text: "${authority.host} --> ${user.BEARER_TOKEN}\r\n"  # user.BEARER_TOKEN retrieves 
                                            # the previously captured variables 
      runScope: RequestHeaderReceivedFromClient  # run the action when the request header 
                                                 # is received from client
Run: fluxzy start -r capture-bearer-token.yaml

Download Fluxzy CLI or pull the Docker image to test these examples.

Browse All Directives

Integrate with Your .NET App

Access all Fluxzy features — from request recording to advanced traffic alteration — in your own code with the open-source Fluxzy NuGet packages.

NuGet Packages Documentation Source Code

Ready to Debug Smarter?

Download Fluxzy for free and start capturing, analyzing, and modifying HTTP traffic in minutes.

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