Null Bounce API

Getting an API Key

If you haven't already, sign up open in new window for a Null Bounce account. It's free to get started, and you will get 100 initial credits for testing.

Once signed up and logged in, click on API-Keys open in new window on the left navigation. Then click on the "Add API key" button. A popup will appear. You need to set a name for a key and click the "Create key" button.


Each call must include the Authorization http-header, with an API key you've created, like this: Authorization: Token 9944b09199c62bcf9418ad846dd0e4bbdfc6ee4b
Replace, 9944b09199c62bcf9418ad846dd0e4bbdfc6ee4b with your key.


The API uses standard HTTP errors to indicate the success or failure of a request. The 2xx series of codes indicates a success, 4xx indicates an error from the client side, and a 5xx error indicates a server side error. Here are the HTTP response codes the Null Bounce API utilizes:

  • 200 Success
  • 400 Bad Request
  • 400 Payment Required
  • 403 Forbidden
  • 415 Invalid Content-Type. It must be application/json
  • 429 Rate Limit Exceeded
  • 500 Internal Server Error

Cross-Origin Resource Sharing (CORS)

Please note that our verification endpoints do not allow cross-domain requests.
This means that you cannot call this API endpoint directly from front-end Javascript code (including any js-framework like Vue, React, or Angular).

Using API-keys directly in a browser is not supported because it exposes private API keys in your client-side application.
These private API credentials can be used to access any data you've uploaded to your account, so they should never be used in a public context like a web browser. Instead, you should create a server side component to make a request to our API to conceal your private API keys. And you can make a request from your frontend to your server and from this server to our API.

API reference

Validate email address


Response Values:

emailStringEmail that was sent for a validation
result[Safe, Invalid, Risky, Unknown]The final result of the validation process. This value should help to determine whether you should send emails to a recipient or not.
status_text[Valid, Invalid, Catch-All, Unknown]This is the result of deliverability testing.
substatus_text[Failed Syntax Check, Mailbox Not Found, Mailbox Quota Exceeded, No Smtp,Failed Smtp Connection, Forcible Disconnect, Mail Server Did Not Respond, Mail Server Temporary Error, Timeout Exceeded, Antispam System, Exception]This value is an additional details of deliverability testing.
is_disposable[true, false]True if the address uses a disposable domain like
is_role[true, false]Is the email role-based. Role emails such as info@, sales@ etc. are not suitable for marketing emails.
is_free[true, false]Is the email from a free email provider like Gmail

Additional information about these parameters is here.

Grab a code for your language:

Try out the API right on this page:

Check Credit Balance


The response is the number of credits that are available on your account.

Try out the API right on this page:

Last Updated: 11/9/2021, 11:35:58 AM