HTTP Debugger alternative

Fluxzy is a cross-platform HTTP debugging proxy. Like HTTP Debugger, it can capture HTTP and HTTPS traffic with no proxy to configure. Unlike HTTP Debugger, it runs on Windows, macOS, and Linux, inspects traffic below the HTTP layer, and ships as both a desktop app and a command-line tool.

This page explains how the two differ and maps each HTTP Debugger feature to its Fluxzy equivalent.

Download Fluxzy Desktop

	HTTP Debugger Pro	Fluxzy Desktop
Operating systems	Windows 10 / 11	Windows, macOS, Linux
Capture with no proxy setup	Yes, system-level	Yes, transparent capture (preview)
Lighter per-app capture	No	Yes (system proxy, hooked browser)
Inspect below HTTP (packets, TLS handshake)	No	Yes
Export to Wireshark with decryption keys	No	Yes (PCAPNG + NSS key log)
TLS client fingerprint control	No	Yes
Command-line / headless version	No	Yes, same engine as the desktop
Configuration as code	No	Yes, portable YAML rules
Source available to audit	No, proprietary	Yes, Fluxzy.Core is open source
OpenAI / Anthropic calls parsed	Raw traffic only	Parsed, streamed responses included
HTTP/2, WebSocket, SSE, gRPC	Yes	Yes
Price	Free for personal use; $129 lifetime for commercial	Free for personal use; paid license for commercial

Most debugging proxies require each application to route its traffic through them, by way of the system proxy, an environment variable, or an application setting. Applications that do not read those settings are not captured. This commonly affects:

• Desktop applications and services that ignore the system proxy
• Runtimes with their own network stack (some Java and .NET clients, Go binaries, Electron apps)
• AI agents and SDKs with hard-coded endpoints
• Android emulators, local development servers, and traffic to localhost

HTTP Debugger avoids this by capturing at the system level: the application connects directly to the destination server, and capture happens beneath it. No configuration is required, and applications cannot opt out.

Fluxzy provides the same model through transparent capture. Instead of registering a proxy, it intercepts traffic at the operating system's network layer, so every process is recorded regardless of its proxy settings. It runs on Windows, macOS, and Linux, each using that platform's native networking. See Transparent capture for the implementation details.

Note. HTTP Debugger's no-proxy capture is mature and is the default on Windows. Fluxzy's transparent capture is in preview, captures TCP only (QUIC and HTTP/3 are not yet covered), and requires a one-time elevation prompt. Its distinguishing property is availability on macOS and Linux.

HTTP Debugger captures system-wide. Fluxzy offers three modes, documented in Capturing HTTPS traffic:

• System proxy — the default. No elevation required. Covers browsers and most HTTP clients.
• Transparent capture — the proxyless, whole-machine mode for applications that bypass proxies. See Capture every app: the transparent tunnel.
• Hooked browser — launches a single browser that already trusts Fluxzy and routes through it, with no system-wide changes.

The following HTTP Debugger features map to Fluxzy as described.

HTTP Debugger	Fluxzy equivalent
Auto-Reply	Mock response action in the rule engine
HTTP Modifier	Header and body rewrite actions
TCP/IP Redirector	Request redirect and DNS spoof actions
Charts and timeline	Per-exchange timing, plus packet-level timing via PCAP capture
Export (Excel, JSON, XML, CSV)	cURL export, saved sessions, PCAPNG with TLS keys
Replay and edit requests	Replay, plus live breakpoints to pause and modify in flight

In HTTP Debugger, Auto-Reply, the HTTP Modifier, and the TCP/IP Redirector are separate tools. In Fluxzy they are actions in a single rule engine, so they compose and can be saved as a file.

Inspection below the HTTP layer. HTTP Debugger stops at HTTP. Fluxzy records HTTP, transport, and TLS in one session and exports to Wireshark with the keys required to decrypt the capture, which keeps the low-level and request views in a single timeline.

Configuration as code. Rules built in the desktop app export to YAML and run unchanged in Fluxzy CLI, headless, in a container, or in CI. HTTP Debugger has no command-line version.

Open core. Fluxzy.Core is open source, so the interception, cryptography, and stream handling are auditable. HTTP Debugger's capture engine is proprietary.

TLS fingerprint control. Fluxzy can present the TLS handshake of a specific client using BouncyCastle, which matters when a server fingerprints TLS to detect a proxy. HTTP Debugger does not expose this.

Parsed AI traffic. Fluxzy parses OpenAI and Anthropic chat completions, including streamed responses, and reconstructs them as conversations. See Debugging LLM API calls. HTTP Debugger records the same calls as raw HTTP.

Fluxzy imports HAR and SAZ session files. Because transparent capture requires no configuration, starting a new capture is usually the fastest path: existing traffic appears decrypted on whichever operating system you are using.

To decrypt HTTPS, install and trust the Fluxzy root certificate once. This is the same step any decrypting tool requires, HTTP Debugger included. The interface model is otherwise familiar: an exchange list on one side, full detail on the other, filters to narrow the list, and rules to modify traffic.

Yes. Transparent capture intercepts traffic at the OS network layer, so every application is recorded with no proxy or per-application setup, including applications that ignore proxy settings. It is in preview and captures TCP traffic. A no-elevation system-proxy mode and a hooked-browser mode are also available.

HTTP Debugger is Windows-only. Fluxzy provides native builds for Windows, macOS, and Linux with the same features and interface.

Yes. Transparent capture operates below the application, so an application cannot opt out of it the way it can ignore a proxy.

Fluxzy is free for personal use with no time limit or feature restriction. HTTP Debugger is free for personal, non-commercial use; its commercial license is a $129 lifetime purchase, while Fluxzy sells a paid license for commercial use.

HTTP/1.1, HTTP/2, WebSocket, Server-Sent Events, and gRPC, with full decryption once the certificate is trusted. HTTP/3 (QUIC) is not yet captured by the transparent tunnel and falls back to TCP.

Yes. The desktop app and the CLI share one engine, and rules are portable YAML, so an interactively built configuration runs unchanged in headless environments. HTTP Debugger has no command-line version.

See the Fiddler alternative and Charles alternative pages.

Download Fluxzy Desktop

• Documentation
• Fluxzy.Core on GitHub