What Is STIR/SHAKEN and Why Does It Matter for Your Business Phone?

You have probably seen Spam Likely appear on your phone when a call comes in. That label is not random — it is the result of a framework called STIR/SHAKEN, and it can affect your business calls too. If your customers are seeing Spam Likely when you call them, STIR/SHAKEN is almost certainly why — and it is something your VoIP provider needs to handle correctly.

STIR/SHAKEN is a set of technical standards developed by the FCC to combat phone number spoofing — the practice of making calls appear to come from a different number than they actually originate from. It is how carriers verify that the caller ID displayed on an incoming call is legitimate. STIR stands for Secure Telephone Identity Revisited. SHAKEN stands for Signature-based Handling of Asserted information using toKENs. Together they form a digital signature system that authenticates the origin of phone calls.

When your business makes a call, your VoIP provider digitally signs it with an attestation level. Full Attestation (A) means the provider fully verified the caller's identity and number — highest trust level, your calls go through cleanly. Partial Attestation (B) means the provider verified the call originated from their network but cannot fully verify the number. Gateway Attestation (C) is the lowest level — the call came from outside the provider's network and has the highest risk of being labeled spam.

If your VoIP provider does not implement STIR/SHAKEN correctly, or if your calls are getting C-level attestation, carriers on the receiving end may label your calls as spam — even when you are making legitimate business calls. This is a real problem for businesses that make a high volume of outbound calls and find their call answer rates dropping.

There are three things to ask your VoIP provider: Do you implement STIR/SHAKEN? What attestation level do my outbound calls receive? How do I register my numbers to improve attestation?

DiaVoice implements STIR/SHAKEN on all outbound calls. Our infrastructure is built on compliant SIP trunking that supports proper caller ID attestation — so your calls reach your customers looking like legitimate business calls, not spam.

STIR/SHAKEN applies to voice calls only — business text messages are governed by 10DLC registration, which is a separate compliance requirement. If your calls are currently being labeled Spam Likely, switching to a compliant provider like DiaVoice resolves the issue.

DiaVoice implements STIR/SHAKEN on all outbound calls — so your customers see your business name, not Spam Likely. Call (256) 724-3100 or visit diavoice.net.