sing-box vs Xray

Throne's core is built on sing-box, and it also contains Xray. Most profiles run on sing-box. Some VLESS profiles and all Xray custom configs run on Xray. This page explains how Throne chooses the core, how to change that choice for VLESS links, and how to fix Reality connection errors.

Two cores in one

sing-box always runs. It handles the local proxy port, TUN mode, routing rules and DNS. Xray runs as a helper inside the same core. It starts only when the running profile needs it, for example when the profile, a hop of its chain or the outbound of a routing rule runs on Xray. sing-box hands that traffic to Xray over an internal local connection, so TUN mode, routing profiles and DNS settings work the same with both cores.

These profiles run on Xray:

Type column	Where it comes from
VLESS (Xray)	vless:// links, depending on the Xray VLESS Preference; VLESS outbounds in Xray JSON; the VLESS (Xray) type in the profile editor.
Custom Xray … Outbound	The Custom (Xray outbound) type; other outbounds in imported Xray JSON.
Custom Xray Config	The Custom (Xray config) type; imported lists of complete Xray configs.

All other profiles, including VLESS, run on sing-box.

Some VLESS features exist only in Xray. A vless:// link that uses one of them is always imported as VLESS (Xray), whatever the preference is set to:

• the XHTTP transport (type=xhttp) and its extra settings,
• VLESS encryption (an encryption value other than none),
• Finalmask,
• a TCP (raw) transport with an HTTP header together with TLS.

Xray messages appear in the same Logs tab. Their detail level is set in Settings → Basic Settings → Logging → Xray Log level.

Choose the core for VLESS links

Settings → Basic Settings → Core → Xray VLESS Preference decides which core a vless:// link gets when you import it:

Option	Links imported as VLESS (Xray)
XHTTP Only	Only links that need an Xray-only feature (see the list above). Reality links stay on sing-box.
XHTTP And Reality (default)	The links above, plus every Reality link.
All VLESS	Every vless:// link.

All other vless:// links become VLESS profiles that run on sing-box.

The preference applies only to vless:// links:

• Clash / Mihomo YAML: a VLESS entry gets Xray only when it uses XHTTP or VLESS encryption. Reality entries stay on sing-box.
• Xray JSON: every VLESS outbound becomes VLESS (Xray).
• sing-box JSON: VLESS outbounds stay on sing-box.
• Profile editor: you choose VLESS or VLESS (Xray) in the Type list yourself.

After you change the preference

The preference affects only profiles that you import after the change. Existing profiles keep their core. To move them to the other core:

• Subscription group: update the subscription (Groups → Update subscription, or right-click the group tab → Update subscription). Throne replaces the affected profiles with new ones of the other type, so their old test results are gone.
• Profile added from a link: add the link again, then delete the old profile.
• Profile you created by hand: its type cannot be changed. Create a new profile with the other type.

If Keep working profiles is on in the group's Advanced subscription settings, old working profiles can stay next to the new ones. Delete them yourself.

Which core does a profile use?

Look at the Type column of the profile list. VLESS runs on sing-box. VLESS (Xray), Custom Xray … Outbound and Custom Xray Config run on Xray.

To also see the security layer, such as Reality, in that column, turn on Settings → Basic Settings → Style → Show Config Security. For VLESS (Xray) and Custom (Xray outbound) profiles, and for chains, the right-click menu also has Share → Export Xray config.

Reality errors with newer Xray servers

Newer Xray servers reject the Reality client of sing-box. The profile then does not connect, and the log shows reality verification failed (#1780).

• Xray 26.7.11 to 26.7.28 accept only clients that report a recent Xray version.
• Xray 26.9.9 and newer require a newer key exchange (X25519MLKEM768) that the Reality client of sing-box does not offer.

The fix is to run the profile on Xray:

1. Open Settings → Basic Settings → Core.
2. Set Xray VLESS Preference to XHTTP And Reality or All VLESS.
3. Click OK.
4. Update the subscription, or add the link again (see After you change the preference).
5. Check that the Type column now shows VLESS (Xray).

This does not help for Reality entries from a Clash / Mihomo YAML subscription, because they always stay on sing-box. If your provider also offers the subscription as a list of links, use that format.

If you run an Xray server from 26.7.11 to 26.7.28 yourself, you can also add "minClientVer": "0.0.0" to the realitySettings of its VLESS inbound. This lets older clients connect. It does not help with Xray 26.9.9 and newer.

Xray in chains

A chain can mix sing-box and Xray profiles, with two limits:

• All Xray hops must be next to each other. Traffic can switch from sing-box to Xray and back only once: sing-box hops, then Xray hops, then sing-box hops. Otherwise the profile does not start, and the log shows "Too many core transitions".
• A Custom (Xray config) profile must be the top hop, and it cannot share a chain with other Xray hops, because a chain can use only one Xray instance.

Group front and landing proxies, and WARP, count as hops too. See Proxy Chains & Custom Configs.

Xray geo files

A Custom (Xray config) profile can have its own routing rules with geoip: or geosite: values. For these, Xray needs the files geoip.dat and geosite.dat. Other profiles and Throne's routing profiles do not use these files; they use rule-sets.

When the files are missing, Throne shows "Geo asset files required" and offers to download them. Click Yes, wait for "Geo assets installed", then start the profile again.

The download addresses are in Settings → Basic Settings → Miscellaneous → Xray Geo Assets, in the fields GeoIP Asset URL and GeoSite Asset URL. Their lists offer the addresses of four sources: Loyalsoldier (global and China, the default), Chocolate4U (Iran), runetfreedom (Russia) and v2fly. Take both files from the same source. Each Download button downloads that file again and replaces the old one.

If a rule names a category that the file does not contain, Throne shows "Geo asset missing category". Choose a source that has this category, then click Download for that file.

Android

• The same setting is in Settings → Core → Xray VLESS preference, with XHTTP only, XHTTP and Reality (default) and All VLESS. It also applies only when you import, so update the subscription after you change it.
• The profile types are VLESS and VLESS (Xray), and the limits for Xray in chains are the same.