API Keys work for v3 API calls and for sending email. API endpoints prior to v3 do not support API keys at this time.
API Keys allow you to generate an authentication credential that is separate from your username and password. They are independent from one another and are easily disposable. You should create unique API keys for each of your applications or servers so that you can easily revoke them without disrupting other systems if needed.
You can use API Key Permissions to define what actions an API Key can be used to authenticate.
For sending via SMTP, provide the string
apikey as the SMTP username, and use your API Key as the password.
Sending an email via a curl request to the v3 mail send endpoint using an API Key would look like:
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If you’re using one of our Open Source Libraries, see the documentation for that specific library on how to send using an API Key.