Nexmo API provides various means of Authentication depending on what product you are using.

API API Key & Secret JSON Web Token (JWT) OAuth
Number Insight


In this document you can learn about:

API Key & Secret

When you create a Nexmo account you will be provided an API key and secret. These can be found in your account settings  in the Nexmo Dashboard.

Note: The secret should always be kept secure and never shared. Be careful when adding it to your codebase to make sure it is not shared with anyone who may use it maliciously. Read more about the Best Security Practices for your Nexmo Account  .

The API key and secret should be included in the parameters of requests you make to the SMS, Conversion, Number Insight or Developer API.

JSON Web Tokens (JWT)

JSON Web Tokens (JWT) are a compact, URL-safe means of representing claims to be transferred between two parties.

JWTs are supported by the Voice API as a means of authenticating your requests. The Nexmo libraries and CLI handle JWT generation using a unique Nexmo Voice Application ID and a Private Key.

Values for the Header are:

Name Description Required
alg The encryption algorithm used to generate the JWT. RS256 is supported.
typ The token structure. Set to JWT.

The values for the payload claim are:

Name Description Required
application_id The unique ID allocated to your application by Nexmo.
iat The UNIX timestamp at UTC + 0 indicating the moment the JWT was requested.
jti The unique ID of the JWT.
nbf The UNIX timestamp at UTC + 0 indicating the moment the JWT became valid.
exp The UNIX timestamp at UTC + 0 indicating the moment the JWT is no longer valid. Minimum time of 30 seconds from the time the JWT is generated. Maximim value of 24 hours from the time the JWT is generated. Default value of 15 minutes from the time the JWT is generation.

If you are not using a Nexmo library you should refer to RFC 7519  to implement JWT.


Some Nexmo APIs support OAuth as a means of authenticating. We provide an in-depth guide on how to authenticate with OAuth here.