Transmog

Transmog is a web debugging proxy. Capture traffic, inspect requests and responses, pause and edit exchanges, replay requests, and save traces for later. The Windows desktop uses Evergreen WebView2. The Rust engine and headless tools also run in the Linux test gate; Linux and macOS desktop products are not qualified.

Features

• Live traffic with request/response inspectors, content search, caller-process attribution, timing waterfalls, and shared connection evidence.
• Breakpoints, header rules, ordered auto-responses, and sandboxed scripts with audit records of traffic changes.
• HTTP/1.1 and HTTP/2 interception, WebSockets over H1/H2, server-sent events, and HTTP/3 origin connections.
• Chromium network profiles with configurable TLS, protocol, and trust settings.
• Streaming gzip, Brotli, DEFLATE, and zstd processing; text, binary, image, and captured-page viewers.
• Compressed .tmcap recording and on-demand body reads, SAZ interoperability, and optional password encryption.

The proxy binds to loopback by default. The desktop guides HTTPS trust setup and restores the previous per-user Windows proxy settings when stopped. Traffic is transient unless saved or recorded. Sensitive-header redaction is off by default in the desktop; Privacy controls newly captured headers, and Save trace can redact the exported copy. See current limitations.

Run the Windows desktop

Follow the build-and-launch guide for the Windows toolchain, locked dependencies and desktop helpers. After launch:

1. Choose Set up HTTPS interception and approve the current-user root certificate installation.
2. Choose Start proxy, then use a browser or application that follows the Windows proxy settings.
3. Inspect captured traffic in the Traffic workspace.
4. Choose Stop proxy to restore proxy settings and let active streams finish.

See building for an unsigned development installer and Windows releases for signed packaging and qualification.

Record from the command line

The separate transmog-cli.exe release asset runs without the desktop or a Rust installation. See releases and the support capture guide for download and signature verification. In PowerShell, run:

.\transmog-cli.exe record --output .\support-trace.tmcap

Reproduce the issue, then press Ctrl+C to stop and save. Guided recording manages the Windows proxy and temporary trust installation; its default private key stays in memory. Review the trace before sharing it.

The CLI guide covers manual proxy setup, inspection, validation, recovery, exports, redaction and passwords. Command help is available without starting a proxy:

.\transmog-cli.exe help
.\transmog-cli.exe record --help

Embed the engine

Rust crates expose the proxy runtime, streaming content processing, interception, automation, capture and application/session services independently of the desktop. Start with embedding, architecture, and the dependency map. The .NET example demonstrates a narrow native ABI.

Transmog uses Hyper for H1/H2, quiche for H3, Tokio for asynchronous I/O, and one BoringSSL family for TLS and cryptography. The desktop uses Tauri/Wry, Microsoft WebUI, Monaco, and an isolated V8 process for scripts.

Development

Python 3.11 or newer is required. Building owns prerequisites and setup; testing lists repository, browser, interoperability and Linux container gates. See the documentation index for feature guides and contracts.

Security and license

A trusted interception CA can read TLS traffic from clients that trust it. Protect its private key, inspect only authorized traffic, and remove the root when no longer needed. Diagnostics exclude private keys and traffic bodies by default.

Transmog is licensed under the MIT License. Dependency licenses are in third-party notices.