Attestation
What is Attestation?
Attestation is the STIR/SHAKEN signal that tells a receiving carrier how much the originating carrier could verify about an outbound call before passing it on. It comes in three levels: A (full attestation), meaning the carrier authenticated the caller and confirmed their right to use the calling number; B (partial), meaning the caller is known but the number's ownership isn't confirmed; and C (gateway), for calls entering the network from an unverified source. Terminating carriers weigh attestation when deciding whether to let a call ring, label it, or block it.
More detail
The levels are defined by the STIR/SHAKEN framework (ATIS-IPT90): full (A) attestation means the originating carrier both authenticated the caller and confirmed their right to the calling number, partial (B) confirms the caller but not ownership of the number, and gateway (C) applies where the call enters the network from a source the carrier cannot fully verify, such as an international gateway.
Attestation is a claim of verification depth, not a verdict by itself — the terminating carrier combines it with its own spam analytics and the number's reputation to decide how to treat the call, so recurring answer-lift generally tracks the move of a business's call mix from C toward A.
Frequently asked
- What is the difference between A, B, and C attestation?
- A (full) means the originating carrier verified both the caller's identity and their right to use the calling number. B (partial) verifies the caller's identity only, not the number's ownership. C (gateway) applies to calls entering the network from an unverified source, so the carrier could verify neither.
- Does full (A) attestation guarantee my calls get answered?
- No single tier guarantees an answer — attestation is one input the terminating carrier's analytics weigh alongside number reputation and calling patterns. In practice, calls signed with full attestation are far less likely to be labeled or blocked, which is why answer rates typically improve as attestation rises.
- Where can I see my attestation level on Orbit?
- The Numbers page tracks each outbound number's attestation level, the share of calls signed at each level, the answer rate each tier earns, and downgrades over time, and the compliance settings area shows the attestation policy and how it applies to your numbers.
See also
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