STIR/SHAKEN is a set of standards that lets phone carriers in the United States (and Canada) check whether the caller ID on a call is legitimate. It was introduced to fight illegal robocalls and caller ID spoofing — and it now quietly affects whether your calls get answered.
How it works, in plain terms
- When you place a call, the originating carrier checks whether you are allowed to use the number in your caller ID.
- It digitally signs the call with an attestation level.
- The receiving carrier verifies the signature and can use the result — together with its own analytics — to decide how to present the call.
The three attestation levels
| Level | Meaning |
|---|---|
| A — Full | The carrier knows the customer and confirms they are authorised to use the calling number. |
| B — Partial | The carrier knows the customer but cannot confirm they are authorised to use that specific number. |
| C — Gateway | The carrier is passing the call along and cannot vouch for its origin. |
Why it matters for your answer rate
A-level attestation does not guarantee your call is shown as trusted, but lower levels make it more likely that analytics engines treat it with suspicion. Combined with complaints or unusual calling patterns, that can lead to "Spam Likely" labels or blocking.
How to get full attestation
- Use numbers you own, bought from or ported to your provider. Calling with a number that belongs to someone else typically leads to lower attestation.
- Verify your business with your provider. On ReachMeLine, complete Business Verification in your account so your identity is on record.
- Keep your caller ID consistent with the account placing the call.
What STIR/SHAKEN does not do
It does not judge whether a call is wanted. A fully attested call can still be labelled as spam if people report it or if the calling pattern looks abusive. Good attestation is the foundation; healthy calling behaviour is the rest of the house.
