Titanium Web Proxy is a cross-platform HTTP(S) proxy for Windows, Linux, and macOS, available as a C# library, a command-line reverse proxy, and a desktop MITM debugger.

What it is

Titanium Web Proxy is an open-source proxy suite written in C# that ships in three interchangeable forms: the Titanium.Web.Proxy NuGet library for embedding a proxy inside a .NET application, the Titanium.Cli command-line tool (invoked as titanium or twp) that runs the same engine as a standalone reverse or edge proxy, and the Titanium Inspector, a native desktop application for intercepting and examining traffic. The library is MIT-licensed and targets .NET 10 or later, while the CLI and Inspector downloads are self-contained builds that need no SDK to run.

The project solves the problem of inspecting and controlling HTTPS traffic without giving up modern protocol support or deployment flexibility. It decrypts and inspects encrypted requests in a desktop interface, and it is built to keep working when a target server refuses a proxied connection: when blocking is detected — for instance through TLS fingerprinting — the proxy automatically falls back to tunnelling that traffic rather than failing. It replaces hand-rolled interception code in .NET applications, and in front of services it takes the place of a separately installed proxy server.

Key capabilities

• Decrypts and inspects HTTPS in a native Inspector on Windows, macOS, and Linux, with AutoResponder, Map Local/Remote, breakpoints, a Composer, HAR export, and curl/fetch output.
• Detects when a server blocks the proxy for reasons such as TLS fingerprinting and automatically tunnels that traffic.
• Speaks HTTP/2 by default with optional HTTP/3, plus WebSocket, gRPC, SSE, and GraphQL rules handled in the same rules grid.
• Runs as a reverse or edge proxy from the CLI, configured by YAML, with load balancing, ACME, and live reload.
• Embeds in .NET through the MIT-licensed Titanium.Web.Proxy package on NuGet.
• Installs as a boot-persistent service via titanium service install -c twp.yaml, alongside foreground operation with titanium run -c twp.yaml.
• Publishes throughput measurements for tiny keep-alive GETs, 64 KB GET/POST bodies, WebSocket, and unary gRPC on the same harness used to benchmark YARP, nginx, HAProxy, and Envoy.

Who uses it and how

• .NET developers who add dotnet add package Titanium.Web.Proxy to an application and start a ProxyServer bound to an address such as 127.0.0.1:8000 to log or filter requested URLs.
• Developers debugging client traffic in the Inspector, replaying requests through Composer, stubbing responses with AutoResponder, and sharing HAR captures.
• Operators running a YAML-configured reverse or edge proxy in front of services, starting it in the foreground during development and switching to titanium service install for machine boot.
• Teams adding a control plane, dashboard, and observability by enabling plus.enabled: true after titanium update --plus.

Getting started

Install the CLI and Inspector from the Download page as MSI, DMG, AppImage, .deb, .rpm, or zip and run titanium run -c twp.yaml; alternatively add the library with dotnet add package Titanium.Web.Proxy.

How it compares

Among the reverse-proxy tools it is measured against — YARP, nginx, HAProxy, and Envoy — Titanium Web Proxy is distinguished by being a .NET library first, so the same MIT-licensed engine can sit in front of services from the CLI or run embedded inside an application for traffic interception. The Inspector and CLI are distributed as self-contained downloads rather than packages requiring a runtime SDK, and benchmark results for both tiny and heavier request sizes are published against those four tools on a common harness.

When to use it — and when not to

The library requires .NET 10 or later and embeds a MITM or reverse proxy into your own process, so you take on operating that process rather than a pre-built server; the CLI, by contrast, ships self-contained and is configured through a twp.yaml file. Note that the Inspector is free for personal and education use only, so commercial inspection use should be checked against the project's terms first, and the deeper control-plane, dashboard, and observability features sit behind the optional Plus tier.

titanium run -c twp.yaml
titanium test -c twp.yaml
titanium version --check
titanium update

dotnet add package Titanium.Web.Proxy
# Prerelease / beta:
dotnet add package Titanium.Web.Proxy --prerelease

using System;
using System.Net;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using Titanium.Web.Proxy;
using Titanium.Web.Proxy.EventArguments;
using Titanium.Web.Proxy.Models;

using var proxyServer = new ProxyServer();

proxyServer.Logging.MinimumLevel = LogLevel.Information;
proxyServer.BeforeRequest += OnRequest;

var endPoint = new ExplicitProxyEndPoint(IPAddress.Loopback, 8000, decryptSsl: true);
proxyServer.AddEndPoint(endPoint);

// Create and trust the root certificate used to decrypt HTTPS traffic.
proxyServer.CertificateManager.EnsureRootCertificate(
    userTrustRootCertificate: true,
    machineTrustRootCertificate: false);

proxyServer.Start();
proxyServer.Logger.LogInformation("Proxy listening on 127.0.0.1:8000. Press Enter to stop.");
await Console.In.ReadLineAsync();
proxyServer.Stop();

Task OnRequest(object sender, SessionEventArgs e)
{
    proxyServer.Logger.LogInformation("{Url}", e.HttpClient.Request.Url);
    return Task.CompletedTask;
}