Fiddler Alternative — A Modern HTTP Debugging Proxy

Looking for a Fiddler alternative that fits your workflow?

You're not alone. Many developers are exploring their options. Fiddler served us well for years, and for some use cases it's still a solid choice. But development has evolved. HTTP/2 is everywhere, we're debugging across multiple platforms, and CI/CD integration matters more than ever.

Download Fluxzy Desktop — Free

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Different tools fit different needs. Here's what we hear from developers who've made the switch.

Fiddler Classic is a capable tool that many of us grew up with. It works well for traditional HTTP/1.1 debugging on Windows. However, if you need HTTP/2 support, cross-platform compatibility, or deeper protocol analysis, you may find yourself looking for additional options.

Fiddler Everywhere brought cross-platform support and a modern UI. It uses a subscription model where advanced features like breakpoints and mocking require a paid plan. Depending on your needs and budget, this may or may not work for you.

If you're looking for something with native HTTP/2 support, packet-level capture, and a free desktop experience, that's where Fluxzy comes in.

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Here's how the tools compare across key capabilities:

Capability	Fiddler Classic	Fiddler Everywhere	Fluxzy Desktop
Price	Free	Subscription (Free tier available)	Free for personal use
Desktop Framework	Native (Windows)	Electron	Tauri (lightweight, native performance)
HTTP/2 Support	❌ No	✅ Yes	✅ Yes
HTTP/3 Support	❌ No	❌ No	🔄 Coming soon
Platforms	Windows only	Windows, Mac, Linux	Windows, Mac, Linux
Raw Packet Capture (PCAP)	❌ No	❌ No	✅ Native support
Open Source Core	❌ No	❌ No	✅ Yes (Fluxzy.Core)
TLS Fingerprinting	❌ No	❌ No	✅ Yes
CLI for Automation	Limited	Limited	✅ Full feature parity
Rule Engine	Basic	Basic	YAML or visual editor, composable
Mock Responses	✅ Yes	Paid tier	✅ Included
Breakpoints	✅ Yes	Paid tier	✅ Included
Session Saving	✅ Unlimited	Limited in free tier	✅ Unlimited
Wireshark Export	❌ No	❌ No	✅ Yes (PCAPNG + NSS keys)

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No subscription required for hobbyists and individual developers. The desktop app includes all features — breakpoints, mocking, unlimited sessions — without upgrade prompts.

We offer paid licenses for professional/workplace use, which is how we sustain development.

Fiddler Everywhere runs on Electron, which bundles a full Chromium browser and can consume significant memory and CPU resources.

Fluxzy Desktop is built on Tauri, using native system webviews and a Rust-based core. The result is a smaller install size, lower memory footprint, and snappier performance. Your debugging tool shouldn't compete with your browser for resources.

Most proxy tools focus on the HTTP layer. They show you requests and responses, which is often enough.

Fluxzy goes further when you need it. It operates at multiple levels: HTTP, transport, and TLS. You can write rules that affect any of these layers and see what's happening at the packet level.

Native PCAP capture means you can export traffic directly to Wireshark. Combined with NSS key logging, you can decrypt and analyze TLS traffic with full protocol detail. This is particularly useful for diagnosing network-level issues that don't show up in HTTP alone.

The same YAML rules that work in Fluxzy Desktop work in Fluxzy CLI. Identically. This means:

• Define rules in your desktop environment while debugging
• Export them to YAML
• Run them in CI/CD pipelines
• Use them in Docker containers
• Apply them in automated testing

Your desktop workflow and your automation workflow are the same workflow.

Some servers inspect TLS fingerprints to detect proxies or distinguish between different clients. This can affect testing accuracy when you need to simulate real browser behavior.

Fluxzy supports custom TLS fingerprinting using BouncyCastle alongside the native .NET TLS stack. This lets you reproduce the cryptographic behavior of specific clients when your testing scenario requires it.

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50+ filter types including host, path, method, status code, headers, cookies, content type, process name, and more. Combine them with AND/OR logic. Save filter presets for reuse.

50+ action types for modifying traffic:

• Add, update, or remove headers
• Inject authentication (Basic, Bearer)
• Mock responses with custom status codes and bodies
• Serve local files instead of remote content
• Redirect requests
• Spoof DNS
• Add delays and throttle bandwidth
• Inject HTML/JavaScript into pages

Edit rules through an ergonomic visual interface or directly in YAML for version control and automation. Both approaches produce the same underlying rules.

Pause any request or response, inspect it, modify it, continue or abort. Multi-level breakpoints let you pause at both the request and response stage of the same exchange.

HTTP/1.1, HTTP/2, WebSocket — all captured and displayed with full detail. See individual HTTP/2 streams. Inspect WebSocket message frames.

Windows, macOS, Linux. Same features. Same interface. Same experience.

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Fluxzy imports SAZ files natively. Your existing Fiddler captures work out of the box.

If you know Fiddler, you'll recognize the mental model. Traffic list on one side, details on the other. Filters to narrow down. Rules to modify. Breakpoints to pause.

Rules can be YAML or visual. Use the ergonomic UI for quick edits, or switch to YAML when you need to share rules with your team, version control them, or run them in a pipeline.

Deeper protocol access. Fiddler shows you HTTP. Fluxzy shows you HTTP, transport, and TLS. You can see packet-level timing, retransmissions, TLS negotiation details.

Lightweight architecture. Built on Tauri instead of Electron, so it runs lighter on your system.

No subscription pressure. You'll never hit a limit and see an upsell modal. The free version is the full version.

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Yes. Fluxzy Desktop is completely free for hobbyists and individual developers. No time limits, no feature restrictions, no request caps. We offer paid licenses for professional/workplace use.

For core HTTP debugging tasks — traffic inspection, modification, breakpoints, mocking — yes. Fluxzy also offers capabilities like PCAP capture, TLS fingerprinting, and composable YAML rules that may fit certain workflows better. Fiddler has a long history and an established ecosystem of plugins and community resources, which can be valuable depending on your needs.

Yes. Full feature parity across Windows, macOS, and Linux. This isn't a Windows-first tool with half-baked ports — it's truly cross-platform.

You can capture HTTP traffic without certificates. For HTTPS interception (seeing decrypted content), you'll need to install the Fluxzy root certificate. This is the same as any MITM proxy.

Charles is a solid tool, but it's paid ($50 license) and doesn't offer PCAP capture or TLS fingerprinting. Fluxzy's rule engine is more powerful and composable. Both are good choices if you want cross-platform support.

Yes, and this is actually a first-class use case. Fluxzy CLI uses the exact same engine as the desktop app. Define rules in YAML, run them headless in CI/CD. Capture traffic in containers. Generate PCAP files for analysis.

The core engine (Fluxzy.Core) is open source and available on GitHub. You can audit every interception mechanism, every cryptographic decision, every stream transformation. The desktop app is freeware built on top of this open core.

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Download Fluxzy Desktop

Available for Windows, macOS, and Linux. Free forever for personal use.

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• Documentation: Full user guide and reference
• GitHub: Open source core engine

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Built for modern development workflows. Give it a try and see if it fits.