PROJECT V / CORE FAMILY
Project V, V2Fly and the Xray core
Open-source projects, runtime cores and graphical clients explain where configurations come from, how connections are handled and where users manage settings.
ECOSYSTEM
Project V and its configuration model
Project V is an open-source ecosystem of proxy and networking tools, with V2Ray as one of its widely used names. Its configuration model separates inbounds, outbounds, routing, DNS and policies: inbounds accept connections from local apps, outbounds define how to reach destinations, and routing selects a path between them. Understanding these layers is more useful than memorizing where a particular button is in one client. It also helps distinguish problems at the local connection-acceptance stage from those at the remote connection stage.
Graphical clients typically generate the core's runtime configuration from interface settings, so avoid editing generated files directly unless you understand how they are managed. Such changes may be overwritten when the client restarts, switches servers or updates settings. For custom rules that need to persist, use the client's rule manager or custom configuration entry point where possible, and note which layer manages them. When reading a manual, distinguish example snippets from complete files; a single field cannot handle the entire connection flow.
CORE FAMILY
What V2Fly and Xray share—and where they differ
The V2Fly community continues development and maintenance of the V2Ray core project. Xray is a separate core that developed from related code. They share configuration concepts, but protocol support, field details and new features do not always match. Capabilities such as REALITY depend on the core in use. A client displaying a particular option does not guarantee that all its parameters work in another core.
When troubleshooting compatibility, note the client, runtime core, protocol, security layer and transport together. Saying only “using V2Ray” is not enough to reproduce an issue. If no profile appears after import, check the content format. If the core will not start, check fields and dependencies. If it starts but cannot connect, verify server parameters and network conditions. Troubleshooting one stage at a time makes it easier to relate actions to logs and avoids treating every error as the same problem.
OPEN SOURCE
Open-source status of the three clients
v2rayN, v2rayNG and v2flyNG are all open-source graphical clients. Their source code is available under each project's license; use, modification and redistribution must follow the applicable terms. Client code, core code and bundled components may have different licenses, so one project's license does not cover every component. Open-source status also does not guarantee that every configuration suits your use case. Check network access permissions and service terms separately.
The three clients focus on managing configurations and connections through a graphical interface; they do not provide remote servers. You still need valid server profiles or subscription content. The subscription provider is responsible for its service address, validity period and access permissions; the client retrieves and uses that information. This site provides download links and technical guidance, not connection credentials. Before sharing screenshots or logs, remove subscription URLs, user identifiers and other access details.
UPDATE PRACTICE
Update clients, cores and subscriptions separately
Client updates mainly affect the interface, configuration generation and integration. Core updates affect connection handling and protocol implementation. Subscription updates synchronize server entries. These are separate operations, not different names for the same update, and one cannot replace another. Updating the client may not help when a subscription has expired; repeatedly refreshing a subscription will not add support for fields missing from the core. Identify the problem first, then use the relevant update path.
Before changing your setup, keep a restorable configuration backup and note the active server, routing mode and listener settings. After an update, check that the client starts, then test subscription retrieval and actual access. With custom JSON, watch for changes to fields and defaults. When an error occurs, return to the specific log instead of disabling all verification or deleting every rule at once. The download center helps you choose packages; setup steps and field details are covered in the guides and JSON reference.
Suggested reading order: start with the getting started guide for installation, check the glossary for unfamiliar terms, and consult the field reference when you need to change a configuration. When a connection issue spans several layers, preserve the smallest reproducible set of steps; it is more useful for diagnosis than repeatedly switching settings.