A faster way to 2FA.

Pre-built with multi-channel failover. No experience required.

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Verification as simple as sending an SMS.

Focus on faster app development and let us take care of onboarding and authentication. Use a single API with ready-made logic to build and test PIN generation, delivery, and failover for more intelligent onboarding and authentication.

See the documentation
We need to verify a phone number
curl -X "POST" "https://api.nexmo.com/verify/json" \
-d "api_key=NEXMO_API_KEY" \
-d "api_secret=NEXMO_API_SECRET" \
-d "number=14155550100" \
-d "brand=MyApp" \
Get your API Key
Businesses Using Nexmo

Get smarter fail-safe, reliable delivery, and tailor-made messaging.

Intelligent Failover

Automatically resend PIN codes via voice (TTS) to customers through one API request without additional code.


Ensure optimum delivery by proactively re-routing messages around congestion—like GPS for your SMS.

Flexible Implementation

Choose from two Verify models: Verify Conversion or Verify Request.
See All Features

Get everything you need with Nexmo Developer.

Read the docs and explore our libraries.

SDKs & Tools

Get up and running quickly in your language of choice.
View our API libraries on Github:
Plus get our command line tool.
Nexmo CLI


Provide feedback, gain, and share knowledge and find out where you can meet us in person via Slack, Stack Overflow, and Github.
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Verify Conversion

Our full-service, per-conversion model allows you to start authenticating phone numbers across the globe with just a few lines of code. Verify manages the PIN code with auto failover to additional channels when needed.

Verify Request

Our per-request model allows our customers to manage their PIN code and customize the failover sequence to additional channels.
See Pricing Details

Let’s build something great together.

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