SVCB Record Lookup

Check SVCB records (RFC 9460 generic service binding) for any service. Free DNS checker.

What is an SVCB record?

An SVCB record ("service binding") is the generic version of the HTTPS record: same wire format, different type code. It lets a service publish where to reach it (host, port, ALPN protocols) and any service-specific parameters in DNS, in a single record.

When to check SVCB

• Diagnosing modern transport upgrades (HTTP/3, DoH, DoQ)
• Confirming an Encrypted Client Hello (ECH) deployment
• Querying experimental service-binding configurations for protocols other than HTTPS

Reading the results

SVCB values share the same wire format as HTTPS records: priority target params. AliasMode (priority 0) points at another name; ServiceMode (priority > 0) carries parameters describing how to reach the service.

Common errors and pitfalls

• Wrong type code: querying SVCB on something that's actually an HTTPS record returns nothing. The two types are deliberately separate.
• Resolvers that don't speak SVCB: many DoH resolvers fall back to raw bytes for unknown types. Cross-check with a modern resolver if results look garbled.

FAQ

SVCB vs HTTPS: which should I look up?

If the service is HTTPS, look up the HTTPS record. SVCB is for everything else (or for cases where a service publishes non-HTTPS bindings).

What protocols use SVCB today?

Adoption is early. Some experimental DoH and DoQ deployments use SVCB to advertise alternate transports. The HTTPS subtype is far more widely deployed.

Background reading

See the DNS Records Explained guide.