STIR/SHAKEN Explained for Businesses Making Outbound Calls
STIR/SHAKEN is a caller ID authentication framework used in United States voice networks.
STIR/SHAKEN is a caller ID authentication framework used in United States voice networks. It was created to help fight illegal caller ID spoofing and restore trust in voice calls. For sales teams, support teams, call centers, and businesses using SIP trunking, understanding caller ID authentication helps when reviewing provider requirements.
But there is a lot of confusion around it. Some businesses think STIR/SHAKEN guarantees that calls will not be labeled as spam. Others think it only matters to carriers. STIR/SHAKEN supports caller ID authentication, but it is only one part of call deliverability.
What STIR/SHAKEN Means
STIR stands for Secure Telephone Identity Revisited. SHAKEN stands for Signature-based Handling of Asserted information using toKENs. Together, they create a framework for authenticating caller ID information on IP-based voice networks.
In practical business terms, it carries information about who authenticated the call and what that provider could verify about the calling number.
When a call is originated, the provider can sign the call with caller ID authentication information. When the call reaches the terminating side, the receiving network can verify that information. Authentication information can help a receiving network evaluate caller identity.
The Three Attestation Levels
STIR/SHAKEN commonly uses three attestation levels: A, B, and C.
Full attestation, often called A-level attestation, generally means the provider has authenticated the customer and verified the customer’s right to use the calling number.
Partial attestation, or B-level attestation, usually means the provider knows the customer but cannot fully verify the right to use the specific calling number.
Gateway attestation, or C-level attestation, identifies a provider’s entry point for a call it did not originate; it does not establish the original customer’s right to use the number.
For businesses, the goal is usually to work with providers and number strategies that support stronger authentication whenever possible.
Why STIR/SHAKEN Matters for Outbound Campaigns
Caller ID trust affects whether people answer. If your calls are unauthenticated, poorly attested, or routed through providers that do not handle authentication well, your calls may face more friction. That can mean lower answer rates, higher blocking risk, or more aggressive labeling.
STIR/SHAKEN also matters because the broader telecom ecosystem is moving toward more accountability. Businesses that make high-volume outbound calls need to show that their traffic is legitimate, authorized, and compliant.
What STIR/SHAKEN Does Not Do
STIR/SHAKEN does not prove that a call is wanted. It does not guarantee compliance with TCPA, Do Not Call rules, consent requirements, or industry-specific regulations. It also does not automatically remove Spam Likely labels.
A call can be authenticated and still be unwanted. If recipients complain, if answer rates are poor, if redial patterns are aggressive, or if the campaign uses bad lead data, the number can still develop a poor reputation.
That is why businesses should think of STIR/SHAKEN as one layer in a larger call deliverability strategy.
How Businesses Can Improve Caller ID Trust
Use numbers that are properly assigned to your business. Keep your caller identity consistent. Avoid using random or misleading caller IDs. Work with a provider that understands SIP trunking, outbound routing, number reputation, and compliance requirements.
You should also monitor campaign-level performance. If a number suddenly drops in answer rate, starts getting complaints, or shows abnormal call completion behavior, investigate early. Telecom problems are easier to fix before the number reputation is damaged.
Further reading
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