Core compatibility
Choose the embedded engine that fits your servers and routing.
Choose a core under Settings → Core. Desktop builds embed four cores in the same binary, so there is no separate core executable to install. The app shows the embedded version next to each choice.
Start with Built-in sing-box for the broadest support for the app’s features.
Compare cores
| Core | Use it for | Limits |
|---|---|---|
| Built-in sing-box | The default TodayCore-based engine, including XHTTP, Reality, and the app’s complete routing feature set. | rigby:// is not supported by the embedded cores. |
| Official sing-box | SagerNet’s sing-box implementation. | No XHTTP; those servers need built-in or Xray. |
| mihomo | Clash Meta and complete Clash configurations. | Skips detected-protocol rules and sing-box .srs / .json rule lists. Uses its own geo data. App TLS fragmentation and SNI settings do not apply. |
| Xray | Xray server handling with the built-in tunnel, DNS, and routing. | No Hysteria, Hysteria2, TUIC, SSH, or Shadowsocks plugins. App TLS fragmentation and SNI settings do not apply. |
Android
Only the built-in core and Xray are offered on Android. The built-in core integrates with Android’s VpnService, and Xray works behind it.
Unsupported profiles
The app asks the selected core which profiles it cannot run. Those profiles are marked with the reason instead of appearing to be usable and failing without explanation.
If a server is marked Needs another core, compare its protocol and transport with this table, switch the core, and try again.
How Xray fits in
Xray handles outbound server connections while the built-in core maintains TUN, DNS, routing, and the kill switch. A password-protected loopback entry point sends Xray’s own transport directly out, avoiding routing it back into itself.
For implementation details, see architecture. For supported link and transport families, see protocols.