There are a number of shared concepts between the Nexmo APIs: the use of JSON Web Tokens (JWTs), signed requests, OAuth tokens, and webhooks. The guides below explain in detail how to use these elements.


  • Applications - Security and configuration information you need to connect to Nexmo endpoints.
  • Authentication – API keys, OAuth, and JSON Web Tokens (JWTs).
  • OAuth – how to use OAuth 1.0a with Nexmo's API.
  • Signing requests – how to cryptographically sign requests.
  • Webhooks – Nexmo's API can send data back to your web server via a webhook.
  • Glossary – A glossary of common terms used throughout the Nexmo platform.

Number format

Within the Nexmo APIs all phone numbers are in E.164 format  . This means that numbers:

  • Omit both a leading + and the international access code such as 00 or 001.
  • Contain no special characters, such as a space, () or -

For example, a US number would have the format 14155550101. A UK number would have the format 447700900123.

If you are unsure how to format the number, the Number Insight API can be used to find correct information about a number.

See also Number format in the Voice API documentation.