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The Operator Foundation

Operator makes usable tools to help people around the world with censorship, security, and privacy.


The Shapeshifter project provides network protocol shapeshifting technology (also sometimes referred to as obfuscation). The purpose of this technology is to change the characteristics of network traffic so that it is not identified and subsequently blocked by network filtering devices.

There are two components to Shapeshifter: transports and the dispatcher.

If you are an end user that is trying to circumvent filtering on your network, or a developer that wants to add pluggable transports to an existing tool that is not written in the Go programming language, then you probably want shapeshifter-dispatcher. Please note that familiarity with executing programs on the command line is necessary to use this tool.

If you are looking for a complete, easy-to-use VPN that incorporates shapeshifting technology and has a graphical user interface, consider Moonbounce, an application for macOS which incorporates shapeshifting without the need to write code or use the command line.

Shapeshifter Transports

The purpose of the transport suite is to provide a variety of transports to choose from. Each transport implements a different method of shapeshifting network traffic. The goal is for application traffic to be sent over the network in a shapeshifted form that bypasses network filtering, allowing the application to work on networks where it would otherwise be blocked or heavily throttled.

Each transport provides a different approach to shapeshifting. These transports are provided as a Go library which can be integrated directly into applications. The dispatcher is a command line tool which provides a proxy that wraps the transport library. It has several different proxy modes and can proxy both TCP and UDP traffic.

These transports implement the Pluggable Transports 3.0 specification. Specifically, they implement the Go Transports API v3.

If you are a tool developer working in the Go programming language, then you probably want to use one or more transport libraries directly in your application.

The following transports are currently implemented in Go:


Replicant is Operator's flagship transport which can be tuned for each adversary. It is designed to be more effective and efficient that older transports. It can be quickly reconfigured as filtering conditions change by updating just the configuration file.

A Swift implementation is also available.


Starbridge is a Pluggable Transport that requires only minimal configuration information from the user. Under the hood, it uses the Replicant Pluggable Transport technology for network protocol obfuscation. Replicant is more complex to configure, so Starbridge is a good starting point for those wanting to use the technology to circumvent Internet cenorship, but wanting a minimal amount of setup.

A Swift implementation is also available.

Shadow (Shadowsocks)

Shadowsocks is a simple, but effective and popular network traffic obfuscation tool that uses basic encryption with a shared password. Shadow is a wrapper for Shadowsocks that makes it available as a Pluggable Transport.

A Swift implementation is also available.


Optimizer is a pluggable transport that works with your other transports to find the best option. It has multiple configurable strategies to find the optimal choice among the available transports. It can be used for numerous optimization tasks, such as round robin load spreading among multiple transport servers or minimizing latency given multiple transport configurations.


For individual installation instructions, see the README's for the individual transports:

Frequently Asked Questions

What transport should I use in my application?

Try Replicant, Operator's flagship transport which can be tuned for each adversary. Email for a sample config file for the adversary of interest. shadow is also a good choice as it works on many networks and is easy to configure.

If you are an application developer using Pluggable Transports, feel free to reach out to the Operator Foundation for help in determining which transport might work best for your application. Email

My application is not written in Go. Can I still use the transports?

Yes, the Go API is only one way to integrate transports into your application. There is also an interprocess communication (IPC) protocol that allows you to control a separate process (called the dispatcher) which provides access to the transports through a proxy interface. When using this method, your application can be written in any language. You just need to implement the IPC protocol so that you can communicate with the dispatcher. The IPC protocol is specified in the Pluggable Transports 3.0 specification and an implementation of the dispatcher is available which you can bundle with your application.

In addition, we have native Swift implementations available for those developers looking to integrate transports directly into their iOS, macOS, or Linux applications: