---
title: FAQ
description: Frequently asked questions about 3x-ui — licensing, supported systems, databases, and clients.
icon: CircleQuestionMark
---

## Is 3x-ui free and open source?

Yes. 3x-ui is open source under the GPL-3.0 license. The source is on
[GitHub](https://github.com/MHSanaei/3x-ui).

## What systems does it run on?

Most major Linux distributions (Ubuntu, Debian, CentOS/RHEL and derivatives,
Fedora, Arch, Alpine, and more) across `amd64`, `arm64`, and other architectures.
It also runs as a Docker container. See [Installation](/docs/guide/installation).

## SQLite or PostgreSQL?

SQLite is the default and is fine for most deployments. PostgreSQL is available
for larger setups via `XUI_DB_TYPE=postgres` and `XUI_DB_DSN` — see the
[environment variables](/docs/reference/env-vars).

## Which client apps work with it?

Any Xray-compatible client — for example v2rayNG, Hiddify, and Clash/Mihomo.
Import a client's share link or QR code, or use a
[subscription](/docs/config/subscription).

## How is 3x-ui different from x-ui?

3x-ui is an enhanced fork of the original X-UI project. It adds broader protocol
support, improved stability, per-client traffic accounting, multi-node
management, a 13-language UI, and many quality-of-life features.

## How do I update?

Re-run the install script (it updates in place), or pull the new Docker image.
See [Installation](/docs/guide/installation) and the
[releases page](https://github.com/MHSanaei/3x-ui/releases).

## Where can I get help?

Join the official Telegram channel [@XrayUI](https://t.me/XrayUI) for
announcements and community support, or open an issue on
[GitHub](https://github.com/MHSanaei/3x-ui/issues). For common problems, start
with [Troubleshooting](/docs/help/troubleshooting).
