Fluxzy

Fluxzy is a traffic-debugging proxy for developers and security engineers working with web, mobile, and API clients. It is best for people who need to capture difficult-to-proxy traffic and inspect or reproduce requests in detail. Perpetual paid licenses make it an appealing work tool, but the free edition is restricted to personal use.

Overview

Fluxzy records, analyzes, and alters HTTP/1.1, HTTP/2, and WebSocket traffic across plain and secure channels. Its proxyless capture can record HTTP and HTTPS traffic without proxy configuration, including from apps that ignore system proxy settings. That makes it especially useful when a client resists ordinary interception; iOS traffic is routed to the proxy instead.

Fluxzy works offline without an account or cloud sync, and the company says it has no telemetry. Fluxzy.Core is GPLv3 open source, but Fluxzy Desktop is proprietary. Desktop downloads publish SHA-256 checksums, CLI downloads SHA-512 checksums, Windows binaries are Authenticode-signed, and macOS builds are signed and notarized—useful assurances for teams vetting software downloads, though not a substitute for an open-source desktop application.

Key features

Traffic rules can edit request and response headers, inject authentication, simulate slow networks, forward requests, spoof DNS, change TLS fingerprints, and force HTTP versions. Breakpoints, replay, response mocking, and proxy chaining extend the tool beyond passive capture: developers can alter or recreate conditions to investigate application behavior.

Fluxzy decodes gRPC and Protobuf traffic either without a schema or with real field names supplied through .proto files. It can also inspect OpenAI, Anthropic, and Google Gemini API requests and responses, including streaming output and tool calls. That combination suits engineers debugging both conventional services and newer API integrations.

Captures can be exported as HAR, Fiddler SAZ, PCAPNG for Wireshark, cURL commands, .http files, or native .fxzy files, giving teams several ways to share or continue analysis in other tools. Official NuGet packages expose the engine to .NET Standard 2.1, .NET 6, and .NET 8 applications. Fluxzy Connect captures Android app traffic through a local VPN.

Pricing

The Community Edition costs nothing and includes all features, but it is for personal use and adds an x-fluxzy-community header. That header and the personal-use restriction make it unsuitable for professional work despite the full feature set.

Pro (Perpetual) costs €49, paid once: one developer gets a perpetual license with no personal-use restriction for Windows, macOS, and Linux. It is the straightforward choice for an individual developer who wants to use Fluxzy at work without a recurring bill.

Enterprise (Perpetual) is a one-time payment with a three-seat minimum. It costs €59/seat for 1–9 seats, €49/seat for 10–49, and €39/seat for 50 or more. The lower per-seat rates reward larger teams, while the minimum makes this plan a poor fit for a small group needing only one or two licenses. Fluxzy offers a full refund when contacted within 14 days of purchase. There is no free trial.

Platforms

Fluxzy supports Android, iOS, Linux, macOS, Windows, API, and self-hosted use. Android capture uses Fluxzy Connect and a local VPN; iOS apps can be routed to the proxy for inspection. The breadth suits teams debugging across client types, while the desktop license plans name Windows, macOS, and Linux.

Who it's for

Fluxzy is a strong fit for developers and security engineers who need to capture, modify, replay, or export application traffic, particularly when proxy settings are unavailable or when gRPC and LLM API traffic is part of the job. It is less suitable for users who require a fully open-source desktop application or need a free license for business use.

Pros and cons

• Pro: Proxyless capture can reach apps that ignore system proxy settings, reducing a common obstacle in traffic debugging.
• Pro: Schema-less gRPC decoding and inspection of streaming LLM API traffic cover specialized workflows beyond ordinary HTTP inspection.
• Pro: Perpetual individual and team licenses avoid recurring subscription costs.
• Con: The free edition is personal-use only and adds an identifying header, so professional users need a paid license.
• Con: The desktop application is closed source even though Fluxzy.Core is GPLv3.
• Con: Enterprise requires at least three seats, limiting its usefulness for smaller teams.

Alternatives

Web Debugging Proxies is a broader category to browse if you want to compare tools before choosing one.

• HTTP Toolkit is another freemium option for Android, iOS, Linux, macOS, web, and Windows; its Hobbyist plan includes basic interception and inspection, manual breakpoints, and built-in HTTP client tools.
• Reqable is a freemium alternative for Android, iOS, Linux, macOS, and Windows. Its Community plan limits use to one device, 100MB of storage, and three rewrite, script, breakpoint, gateway, and mirror rules.
• NetworkSpy offers a free plan with limited LLM token-stream analysis, breakpoints, resource mapping, custom viewer building, and scripting, and also has a free trial.
• mitmproxy is a free, open-source interactive HTTPS proxy for Linux, macOS, self-hosted, web, and Windows use.
• Mediator is a free, Apache-2.0-licensed cross-platform GUI gRPC debugging proxy.
• Whistle is a free alternative available on Android, iOS, Linux, macOS, web, and Windows.
• Fiddler Everywhere is a paid option with a free trial for Android, iOS, Linux, macOS, and Windows.
• Proxyman is a paid alternative with a free trial across Android, iOS, Linux, macOS, and Windows; its evaluation plan excludes WebSocket preview, mobile apps, and Network Extension.

Verdict

Choose Fluxzy if you need a capable traffic proxy for professional debugging, especially for apps that defeat proxy configuration, gRPC, or streaming LLM APIs. Its broad capture and editing toolkit and perpetual licenses are compelling; look elsewhere if your priority is an open-source desktop app or a free license for work.