What Is STIR/SHAKEN and Why Does It Matter for Businesses Calling the US?

If your business makes calls into or within the United States, STIR/SHAKEN is an important part of how those calls are authenticated.

STIR/SHAKEN is the US caller ID authentication framework designed to reduce spoofed calls, illegal robocalls and telephone fraud.

For legitimate businesses, it helps US networks assess whether a call really comes from the telephone number being presented.

Apollo Cloud Solutions Limited holds its own STIR/SHAKEN certificate and is listed on the official US STI Policy Administrator’s Authorised Providers Register. This allows Apollo to authenticate eligible US calls using its own credentials rather than relying solely on an upstream carrier.

For customers with US operations, that provides greater control over an increasingly important part of business communications.

What does STIR/SHAKEN stand for?

STIR stands for Secure Telephone Identity Revisited.

SHAKEN stands for Signature-based Handling of Asserted information using toKENs.

Together, STIR and SHAKEN provide the technical framework used to authenticate the identity associated with a telephone call.

When an eligible call is made, the originating communications provider can digitally sign the call using its STIR/SHAKEN certificate.

The receiving network can then verify that signature and obtain information about the provider that authenticated the call and its level of confidence in the caller’s right to use the telephone number.

In simple terms, STIR/SHAKEN helps US telephone networks answer:

“Can we trust that this call really comes from the number it claims to come from?”

Why did the United States introduce STIR/SHAKEN?

STIR/SHAKEN was introduced because the United States had developed a major problem with illegal robocalls, scam calls and caller ID spoofing.

Modern VoIP technology made it inexpensive and relatively easy for fraudsters to make very large numbers of calls while disguising the telephone number from which those calls really originated.

A fraudulent caller could make a call appear to come from a local business, bank, government organisation or another trusted telephone number.

As the volume of fraudulent and spoofed calls increased,trust in caller ID declined.

In 2019, the United States passed the TRACED Act, which strengthened the Federal Communications Commission’s powers to combat illegal robocalling and accelerated the adoption of caller ID authentication.

STIR/SHAKEN became a central part of that approach.

The objective is not simply to stop calls. It is to give telephone networks better information about the identity behind those calls.

What happens if a business call is not authenticated?

An unauthenticated call does not automatically mean that the call is fraudulent or that it will be blocked.

However, it reaches the US network with less evidence supporting the legitimacy of the caller identity.

That can increase the risk of calls being labelled as spam or suspicious, being blocked, receiving lower answer rates or being treated less favourably by carrier reputation systems.

For businesses that depend heavily on outbound calling, the commercial consequences can be significant.

Consider a recruitment consultant trying to reach candidates, a sales team calling prospects, an account manager contacting customers or a support team returning customer calls.

If the recipient’s mobile displays “Spam Risk”, “Potential Spam” or a similar warning, the likelihood of that call being answered can fall dramatically.

This is why call authentication is no longer purely atelecoms compliance issue.

It can directly affect customer contact, sales performance and brand reputation.

Does STIR/SHAKEN stop calls being marked as spam?

No. STIR/SHAKEN authentication is one important trust signal, but it is not the only information used by US carriers.

Networks and analytics providers may also consider calling patterns, complaint history, call volumes, number reputation and other indicators.

A properly authenticated call can therefore provide a stronger foundation for trusted calling, but STIR/SHAKEN certification cannot guarantee that every call will be delivered or never labelled as spam.

That distinction is important.

What are STIR/SHAKEN attestation levels?

STIR/SHAKEN uses different attestation levels to indicate the signing provider’s confidence in the call.

A attestation, sometimes called Full Attestation, indicates that the provider knows the customer and has verified their right to use the telephone number.

B attestation, or Partial Attestation, indicates that the provider knows the customer but cannot fully verify the customer’s right to use the calling number.

C attestation, sometimes called Gateway Attestation, is generally used where the provider is introducing the call into the network but does not have sufficient information about the original caller.

Having its own STIR/SHAKEN credentials gives a communications provider greater control over this authentication process.

It does not mean every call automatically receives A attestation. The appropriate attestation still depends on what can legitimately be verified.

Why does it matter whether your telecoms provider has itsown STIR/SHAKEN credentials?

Many UK communications providers use upstream international or US carriers to carry and authenticate their US traffic.

There is nothing inherently wrong with that model.

The issue is control.

An upstream carrier may not have the same direct relationship with the end customer or the same level of information about the telephone number being presented.

A communications provider with its own STIR/SHAKENcertificate can participate directly in the US authentication framework.

Where the relevant requirements are satisfied, it can authenticate eligible calls using its own credentials.

For customers, that creates a clearer authentication chain and reduces reliance on another carrier further down the network to make the authentication decision.

Does Apollo Cloud have its own STIR/SHAKEN certificate?

Yes. Apollo Cloud holds its own STIR/SHAKEN certificate and is listed on the official US STI-PA Authorised Providers Register.

What does Apollo Cloud’s STIR/SHAKEN capability mean for customers?

For Apollo customers making eligible US calls, it means Apollo can authenticate calls using Apollo’s own STIR/SHAKEN identity.

That provides greater control over call authentication and attestation, reduces dependence on upstream providers and gives customers a communications partner that understands the US regulatory environment surrounding business calling.

It also reflects Apollo’s wider investment in international telecommunications capability.

Why is international telecoms experience important?

Providing international communications is more complicated than simply supplying a foreign telephone number.

Different countries have different rules covering numbering, caller identity, emergency calling, portability, regulation and call authentication.

Carrier relationships also matter.

Apollo has considerable experience supporting businesses with communications requirements across the UK, United States and Europe, including international telephone numbers, US calling, global SIP and VoIP services, international call routing and multi-site unified communications.

That experience is particularly valuable for UK companies expanding internationally.

A business may want one communications platform across its organisation, while still needing to comply with very different telecoms rules in each country.

Apollo helps customers navigate those differences while maintaining a consistent communications experience.

Why choose Apollo Cloud for US business calling?

If your business has offices in the United States, is expanding into the US or regularly calls American customers and prospects, your communications provider needs to understand more than tariffs and telephone numbers.

It needs to understand caller identity, authentication, compliance, carrier relationships and international call routing.

Apollo combines its own STIR/SHAKEN credentials with extensive international telecoms experience and the personal service our customers expect from us.

For us, STIR/SHAKEN is not simply another certificate.

It is part of building a communications platform that can support our customers wherever their businesses take them.

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