Identity verification API: How to get started and what to keep in mind

Identity verification doesn’t always occur in one system. There are often three or four vendors stitched together, with a lot of manual work filling the gaps. One vendor handles document verification, another does sanctions screening and someone on your team is collecting documents over email, storing them in a shared drive and flagging exceptions in Slack.

But that's expensive to run and hard to scale. Every extra vendor means another integration and contract to manage, and manual work slows down onboarding while pulling compliance staff away from the cases that actually need them. You're also under pressure to keep onboarding fast and frictionless, but not so fast that fraudsters slip through.

An identity verification API is how many businesses solve this: connecting your application to the databases and checks that confirm a customer's identity and automating the decisions that follow.

This article covers:

How does an identity verification API work?
What are the different types of identity verification APIs?
When it makes sense to integrate an identity verification API
What to look out for in an identity verification API
How to get started with our identity verification API

Ready to unify your verification process and onboard genuine customers faster? Book a demo to see our identity verification API in action.

How an identity verification API works

An identity verification API is the link between your platform and the external databases or verification services that do the actual checking of a customer’s identity.

Here's what that usually looks like during the onboarding process:

A customer types in their details, such as their name, date of birth and address and your system passes that information through the API.
From there, it gets checked against relevant data sources, like credit reference data or government records or run through a verification method such as document verification or sanctions screening.
The API then sends the result back to your system, which decides what happens next: approve the customer, ask for more information, try a different verification method or hand the case off to a person for review.

But here's the catch: two identity verification APIs can receive the exact same information, such as the same name, date of birth and address and still come back with different answers.

That's because providers check those details against different data sources, use different matching logic and incorporate different fraud signals into their decision.

What are the different types of identity verification APIs?

Different verification APIs handle different parts of the identity verification process. Understanding what happens behind each API type can help you decide which capabilities you need.

Identity data verification

An identity data verification API allows your website or app to submit customer information, such as a name, address, date of birth or national identification number, to a verification service. The information may be collected through a form and sent as structured fields in an API request.

The API checks the submitted information against relevant trusted data sources, which may include credit reference agency databases, government registries and other consumer records.

Depending on the provider, the API might return field-by-field match results. For instance, the response could show exactly which individual attributes passed, failed or returned an inconclusive match.

You can also read our guides to KYC APIs and KYB APIs.

Document verification

A document verification API receives photos or scans of physical ID documents, like a driver's license or passport.

On the provider's end, optical character recognition (OCR) automatically extracts the text fields so the customer doesn't have to fill out long forms. The platform also performs authenticity and tampering checks. It checks for template consistency, altered text, barcode patterns and physical security features like holograms to flag fake or tampered ID documents.

The API matches the document against ID templates in the provider’s database, then returns the extracted customer information alongside a pass or fail status, though exact outputs depend on the provider.

Biometric verification

A biometric verification API receives a short selfie video or photo taken by the user during onboarding.

Passive or active liveness detection verifies that a real, live human is in front of the camera to protect against presentation attacks using printed photos, masks or deepfake videos.

The live face is then compared to the photo extracted from the scanned identity document. What comes back through the API is typically a face match confidence percentage, paired with confirmation that the liveness check passed.

Fraud and device intelligence

A fraud and device intelligence API receives technical signals sent automatically by the user's phone or browser.

The platform uses those signals to check for red flags on the connection itself: is the user hiding behind a proxy or VPN, running a device emulator, or relying on automated bot scripts? The result that gets returned is usually a background risk score, along with specific risk labels your onboarding rules can act on.

Sanctions and watchlist screening

A sanctions screening API receives basic identity text, including full name, date of birth and country of residence.

The platform compares those details against its screening datasets, which may include regularly updated sanctions lists from authorities such as the Office of Foreign Assets Control (OFAC) and the UN Security Council.

Smart matching algorithms may account for aliases, name variations and translations from non-Latin scripts like Cyrillic, Arabic or Chinese.

The platform returns screening results through the API. These may indicate that no potential matches were found or identify potential matches with details such as the issuing authority, list name and a match score.

When it makes sense to integrate an identity verification API

There's a point where manual verification stops being a minor inconvenience and starts costing you customers, time or both.

An API integration is usually the solution. Here are three example scenarios where it makes sense:

You want verification built directly into your native customer experience. An API sends and receives verification data behind the scenes, so you can keep customers inside your app instead of redirecting them to third-party websites.
You need verification outcomes to trigger automated actions in your application stack. Your software can act on API responses instantly, such as activating an account when a check passes or triggering step-up authentication when a risk flag appears.
Your application volume is growing beyond what manual processing can handle. API calls initiate checks and return structured decisions automatically, so your team doesn't have to copy data between systems.

A KYC API platform can solve the fragmentation caused by using multiple vendors and systems, slow customer onboarding due to manual compliance processes, low conversion rates due to a poor customer experience, and poor match rates caused by inadequate customer information.

It also supports stronger fraud prevention and helps meet evolving compliance requirements in regulated industries.

KYC verification APIs work by integrating with trusted data sources and watchlists to verify identities, assess risk, and return structured results through a single API endpoint. Based on the results, you can automatically approve low-risk customers, trigger additional checks for higher-risk cases, or route exceptions to manual review.

Some factors to consider when choosing a KYC API provider include data coverage and quality, workflow flexibility, integration ease, scalability, and reliability, including high uptimes.

For financial institutions and other financial services providers, it’s especially important to evaluate security measures, support for AML regulations, and overall regulatory compliance.

Traditional KYC software is a separate system, while an automated KYC solution is designed to integrate into your existing systems. What’s more, traditional KYC software is likely to rely on manual processes more frequently, whereas a KYC API solution conducts identity verification in real time.

KYC APIs offer other benefits too, such as greater adaptability and personalization: they support dynamic workflows, and it’s easier to change rules and thresholds without re-engineering your entire system. Additionally, KYC APIs are easier to scale because, unlike with traditional software, you don’t have to add more licenses, users, or manual review capacity as you grow, or integrate with new tools or vendors in each market.

What to look for in an identity verification API

Not every identity verification API offers the same depth of data, flexibility or control, so…

Look at the results you get back from a verification request

A pass or fail result is only part of the picture, so it helps to look at how much the response actually gives your systems to work with. For data-based verification, can you see which identity attributes matched, whether the result was inconclusive or why the check couldn't be completed?

That level of detail is important because a more informative response means your platform can treat different failures differently: retry with another source, ask the customer for one specific detail or send it to manual review.

Check for fallback options and step-up capabilities

Find out what your options are when one method or data source doesn't give you enough confidence. Can you try another data source, bring in more risk signals or move from data-based verification to document or biometric checks?

And just as importantly, how are those capabilities accessed? Can your platform reach several verification methods through the same API or will your developers be stuck building and maintaining a separate integration for each one?

You want enough paths built into your integration that an inconclusive first check isn't a dead stop.

Consider which risk signals you can send and receive

Some APIs stop at basic identity attributes. Others can pull in device, email, phone, IP/location, behavioral or velocity data, too.

So, confirm which camp your provider falls into, and then look closely at what comes back. Do you get a single risk score, individual signals, reason codes or some mix of all three?

"Offers fraud detection" sounds good, but what you really want to know is how much of that intelligence actually reaches your systems in a form you can use.

Determine how much control you have over API-driven decisions

Having access to several verification methods only gets you so far. You also need to know how your platform decides when to reach for each one.

Can your team configure thresholds, rules, sequences and escalation paths based on things like the initial result, risk signals, market or use case? And where does that decision actually get made? Some APIs return a result for your team to interpret, while others let you configure the decision logic in the provider’s platform and return a ready-made decision.

You should also ask how difficult that logic is to change later. If you want to tweak a threshold or change when a customer gets stepped up, does that mean new development work or can risk and compliance make the change themselves?

Match global coverage to your actual regional requirements

A high country count doesn't tell you much about what the API can actually do in any one of those countries.

A good shout is to dig into which data fields, verification methods, document types and risk capabilities are supported, market by market, everywhere you plan to operate.

Required inputs can shift from country to country, too, which affects how you design your forms and your integration. And if international expansion is on the roadmap, find out now whether new markets come through your existing setup or if each one means another round of development.

How to get started with GBG's identity verification API

You've already seen why fragmented, manual verification is hard to scale, and why balancing speed with compliance is such a tightrope walk. As an identity verification and KYC and KYB provider, this is where we can help.

Our identity and fraud platform brings identity verification, fraud prevention and compliance capabilities together through a single API and orchestration platform.

Here's how it works with GBG:

Add identity verification capabilities without adding more integrations

Working with us, you get access to 110+ identity and fraud modules through a single API, covering identity data verification, document and biometric verification, anti-money laundering (AML) and watchlist screening and fraud intelligence.

Your developers connect your system to our platform once, rather than building and maintaining a separate integration for every one of those checks, and bring whatever you need into a single verification workflow.

That flexibility makes expanding into new markets easier. Our platform covers hundreds of identity data sources across 50 countries, supports 8,500+ ID types across 195 countries and screens against 450+ PEP, sanctions and adverse media watchlists. So when you expand into a new country or a regulation changes, you can switch on the additional data sources, ID types or watchlists you need within your existing integration.

It's not just your developers who feel the difference, either. With case management, compliance teams end up handling more of the process in one place, instead of bouncing between several disconnected systems.

Automate routine checks so that your team can focus on the exceptions

An API can trigger verification checks automatically as part of onboarding, so your employees aren't manually starting checks and shuttling information between systems.

With our platform, identity and compliance checks run on their own, and the results decide what happens next – no one has to kick off or review every single step.

That doesn't mean every applicant runs through the same set of checks, though.

Dynamic workflows weigh the information and risk tied to each user to decide whether they can proceed or need additional checks or manual review. Our identity data covers 4.4 billion people worldwide. If the first source isn’t conclusive, checks waterfall to additional sources, so more genuine customers are verified automatically and fewer face document requests or manual review they don’t need.

When a case does need more scrutiny, you can bring in additional signals or checks. GBG Trust, for instance, adds fraud intelligence informed by activity across 28+ sectors, and document and biometric verification can step in when you need stronger identity assurance.

Fewer routine applications land on a compliance officer's desk as a result. Your team can focus their attention on high-risk exceptions, while genuine customers get onboarded quickly.

Test and optimize your verification journeys without engineering effort

The verification flow you launch likely won't be the one you need a year from now. Fraud tactics evolve, regulations change and performance data will highlight friction points you didn't anticipate at launch.

Our low-code workflow tools let your risk and compliance teams adjust thresholds, reorder checks, or update escalation paths with expert guidance, minimizing extensive engineering work.

Say too many genuine applicants are getting referred for document verification. Rather than guessing at a solution, GBG Go's A/B testing lets you run a different workflow against the current one and compare the results side by side.

Test whatever matters most to your business: a sequence that lifts automated approvals, a threshold change that cuts unnecessary referrals, or a new escalation path for a specific type of case.

That means you can keep improving the process as you scale, rolling out changes on your own timeline. And over time, your verification strategy can evolve right along with your business.

We know that our solutions might not be the right fit for every type of business there is, so here are four other solutions to look at:

4 other identity verification APIs to consider

Trulioo

Trulioo¹ combines broad global reach with no-code flexibility, bringing data, documents, biometrics and fraud intelligence together in one platform. Its no-code builder lets you put together custom KYC and KYB verification flows without needing a developer for every change.

The REST API covers both consumer and business verification, along with AML and other regulatory use cases. Trulioo also draws on hundreds of data sources across more than 100 countries.

Persona

Persona² gives developers control over both the logic and the look of verification. Its API brings identity verification, compliance and fraud prevention into your system, and you can update flow logic based on your risk tolerance or what your users need.

The Flow Editor goes a step further, letting you build a fully branded experience with fonts, buttons and assets. Developers can also mix and match automated verification modules directly through the API, from government ID verification to biometrics, database checks and document authentication, depending on your risk thresholds and compliance requirements.

Socure

Socure's³ strength is in its decisioning: its dynamic workflow builder pairs a no-code interface with real-time testing and third-party data integrations, and you can build rules that factor in historical events, relationships and velocity patterns across your organization.

The API runs on a REST-based architecture with sandbox testing and real-time processing.

Veriff

Veriff⁴ is built around document- and biometric-led verification with a wide document footprint spanning thousands of ID types across 230 countries and territories.

Its API lets you integrate multiple verification modules into your own system, including API-based biometric authentication and liveness detection, alongside capabilities like proof of address, age validation, database verification and AML screening.

Take control of your customer onboarding with a single API

Managing identity verification through separate vendor integrations and manual reviews creates operational bottlenecks that slow down your growth.

Connecting your application to an identity verification API helps you automate routine checks, reduce friction for genuine customers and maintain compliance across borders.

Our platofrm brings data matching, document verification, biometrics and fraud intelligence together through a single API. Your compliance team gets full control over onboarding rules, while your customers can enjoy a fast, easy signup process.

Ready to see how GBG Go can simplify your identity verification setup? Request a demo with our team today.

FAQs: Identity verification API

What information do you need to use an identity verification API?

The information required depends on the verification method you run. For basic identity data checks, you need standard text fields like full name, date of birth, residential address, or a national identification number like a Social Security Number.

For document and biometric verification, you need photos or scans of an official identity document along with a live selfie image captured on the customer's device.

Can one identity verification API handle multiple types of verification?

Yes, provided you choose an end-to-end orchestration platform rather than a point-solution API. Platforms like GBG Go connect your platform to identity data checks, document verification, biometric liveness, sanctions screening and device intelligence through a single API integration.

How long does it take to integrate an identity verification API?

Integration time depends on the complexity of your workflow and the quality of the provider's documentation. Basic API integrations using pre-built SDKs and clear documentation can be completed in a few days.

More complex workflows involving custom decision logic, multiple fallback paths and CRM data syncing typically take a few weeks to build and test.

*Disclaimer: Information relating to third-party products and companies referenced in this article is based on publicly available sources and official publications at the time of writing. While reasonable efforts have been made to ensure accuracy, product features, positioning and company information may change and GBG does not guarantee that all information remains current or complete.

Nothing in this article constitutes an endorsement, recommendation or ranking of any third-party provider. Readers should consult each provider’s official website and conduct their own assessment before making any purchasing decisions.

To request an update or correction, please contact press@gbg.com.

Sources:

1. https://developer.trulioo.com/reference/trulioo-platform-api-endpoints

https://www.trulioo.com/solutions/global-identity-platform

2. https://docs.withpersona.com/api-quickstart-tutorial

3. https://help.socure.com/riskos/reference/get-started

https://www.socure.com/solutions/riskos

4. https://devdocs.veriff.com/apidocs/veriff-public-api-guides