Project V is a good starting point for understanding the V2Ray ecosystem. V2Fly and Xray are related core families, while GUI clients provide interfaces for managing nodes and system settings.
Project History and Differences in Capabilities
V2Ray uses a configuration model built around inbounds, outbounds, and routing, separating traffic reception, protocol handling, and path selection. V2Fly continues the maintenance and development of the V2Ray project, while Xray evolved from related code into its own implementation and extensions. They share some technical concepts, but their features do not evolve in lockstep. Similar-looking configurations do not mean every field is interchangeable.
When following a guide, check both the client and the core. Features such as REALITY require support in the relevant implementation. Importing a node, generating a valid configuration, and establishing a connection are three separate checks. If an error mentions an unknown field or unsupported transport parameter, check the core's capabilities before changing routing.
Graphical Clients and Runtime Cores
v2rayN, v2rayNG, and v2flyNG are open-source GUI clients for managing subscriptions, editing settings, and controlling services. v2rayN targets desktop systems and centralizes configuration and core selection. v2rayNG is primarily for Android and Xray; v2flyNG offers another way to use V2Fly on Android. They share some workflows, but their interfaces and configuration backup formats are not identical.
When moving from a computer to a phone, share links and QR codes are usually easier to verify than copying an entire configuration directory. After importing, check that the node is selected, the app is included in proxy coverage, and DNS and routing suit the new device. Do not reuse desktop listening addresses, file paths, or permissions on Android unchanged.
Open-Source Licenses and Free Use
Open source means the code is available under its applicable license, which permits viewing, using, and modifying it within the license terms. The V2Fly core uses the MIT License, and Xray-core uses the MPL-2.0 License. GUI clients and their dependencies have their own applicable licenses; a core's license does not automatically apply to every component in an installer.
These clients are free to use, but the client and remote service are independent. Subscription charges, data limits, and node expiration are set by the service provider. Separating “can the tool start?” from “is the remote service available?” helps avoid mistaking an unavailable service for a reason to buy another client.
Updates, Compatibility, and Rollbacks
Client updates can change the interface, configuration generation, and bundled core dependencies; core updates can change protocol support or behavior. Before updating, save subscription groups and custom rules, and note which traffic-capture method currently works. After updating, test your existing node first, then restore extra settings one at a time. Avoid changing the client, node, and DNS all at once.
If something goes wrong, reproduce the issue and check startup logs before deciding whether the error points to a configuration compatibility problem. Updating a subscription refreshes the node list from the provider; it does not update the client or core. The download page and quickstart cover installation and setup, while the troubleshooting guide links log, port, DNS, and system proxy checks to specific symptoms.