Project X Documentation

The documentation is organized by user expertise level:

• Project X for Dummies (Level 0): User insights and fundamental guidance for absolute beginners.
• Beginner Tips (Level 1): Intermediate usage methods for those who have mastered the basics.
• Advanced Documentation (Level 2): Specialized tips and guidance for advanced users.

The official documentation for Project X is hosted at the following URL. This site contains all the content presented in the repository's documentation structure.

https://xtls.github.io/

Xray-core provides a comprehensive suite of networking and security features:

• Original Protocols: Includes VLESS, XTLS, XUDP, XHTTP, and REALITY, covering proxy, flow control, multiplexing, transport, and security layers.
• Advanced Routing: A flexible routing and DNS system that allows fine-grained traffic scheduling based on domain, IP, port, protocol, process, and user.
• Traffic Obfuscation: Uses VLESS fallback, REALITY, XTLS flow control, and FinalMask to reduce traffic fingerprints and enhance anti-detection capabilities.
• Modular Composition: Proxy protocols, flow control modes, transport layers, and routing systems can be freely combined to suit different scenarios.
• Low Resource Consumption: VLESS eliminates redundant encryption and uses Splice to reduce forwarding overhead, making it suitable for low-power devices like OpenWRT or Raspberry Pi.

This documentation is specifically designed for beginners with zero foundation who wish to learn how to self-host a VPS (Virtual Private Server) for secure internet access.

This guide is NOT for:

• Technical experts or advanced users.
• Users who prefer using 'Airports' (subscription-based proxy services).
• Users who want to use one-click automated scripts.
• Users who do not wish to learn the underlying technical processes.

If you are looking for a quick, automated, or managed solution, you should skip this documentation.

This guide is specifically designed for newcomers with zero technical background who want to learn how to self-host a VPS (Virtual Private Server) for circumvention purposes.

This guide is NOT for:

• Technical experts or gurus.
• Users who prefer using "Airports" (VPN/Proxy service providers).
• Users who want to use one-click scripts without understanding the underlying process.
• Beginners who are unwilling to tinker or learn basic technical foundations.

HTTPUpgrade is a protocol that implements HTTP 1.1 upgrade requests and responses, similar to WebSocket. This allows it to be reverse-proxied by CDNs or Nginx. It is designed for high efficiency by avoiding the full WebSocket protocol implementation.

Note: It is intended to work with security protocols like TLS rather than being used standalone.

::: danger It is recommended to switch to XHTTP to avoid significant traffic fingerprints such as ALPN is http/1.1. :::

mKCP is a streaming protocol modified from the KCP protocol. It allows for the ordered transmission of arbitrary data streams over UDP.

Key Characteristics:

• Transport Layer: Uses UDP for all communications.
• Connection Model: There is no formal handshake process. A session is identified by a unique Conv (Connection) ID carried in every packet. When a packet is received, the receiver uses the Conv ID to determine if it belongs to an existing session or a new one.
• Data Unit: mKCP splits data streams into packets. Each packet contains one or more Segments.
• Versioning: There is no version number, and compatibility between different versions is not guaranteed.

REALITY is a modified form of TLS that uses the appearance and handshake characteristics of a target site as camouflage. It makes traffic shape consistent with ordinary web browsing.

Key Requirements:

• It can only be used with RAW, XHTTP, or gRPC transport methods.
• For optimal performance, enable REALITY together with a suitable XTLS Vision flow-control mode.
• On the client side, it requires handling a fully random session ID and custom certificate verification.

Security Warning: For camouflage reasons, Xray directly forwards traffic that fails authentication to the target site. If your target is behind a CDN like Cloudflare, your server may be abused as a port forwarder. To mitigate this, use a proxy like Nginx to filter SNI values or use limitFallbackUpload/limitFallbackDownload to rate-limit unverified traffic.

Mux.Cool is a multiplexing transport protocol (version 1 Beta) designed to transmit multiple independent data streams (sub-connections) within a single established reliable data stream (the "main connection").

Key Concepts

• Main Connection: The underlying reliable stream (e.g., TCP) that carries all multiplexed traffic.
• Sub-connection: An independent logical stream within the main connection, identified by a unique ID.
• Frames: The unit of transmission. Each frame carries data for a specific sub-connection.
• Symmetric Format: Both clients and servers use the same frame structure to send and receive data.

Dependencies

Mux.Cool must run on top of an established reliable data stream.