Authentication

Every request must carry your account credentials. There are two ways to send them:

Method	Header	Use it when
X-API-Key (recommended)	`X-API-Key: <key>`	You are building a new integration. It is one value with no encoding step.
HTTP Basic	`Authorization: Basic <base64>`	Your HTTP client or platform only supports username and password.

Get your credentials

Open Integrations → API Keys in DirectIQ. You will find:

X-API-Key, for X-API-Key authentication.
Client ID and Client Secret, for HTTP Basic authentication.

Option 1: X-API-Key (recommended)

Send your key in the X-API-Key header:

curl https://api.directiq.com/v2/senders \
  -H "X-API-Key: YOUR_X_API_KEY"

📘
One key, two uses
The X-API-Key is also the password for the DirectIQ SMTP gateway. If you regenerate it, update both your API integration and your SMTP settings.

Option 2: HTTP Basic

Use your Client ID as the username and your Client Secret as the password. Most HTTP clients build the header for you:

curl https://api.directiq.com/v2/senders \
  -u "YOUR_CLIENT_ID:YOUR_CLIENT_SECRET"

To build the header yourself, Base64-encode client_id:client_secret and send it with the Basic scheme:

Authorization: Basic WU9VUl9DTElFTlRfSUQ6WU9VUl9DTElFTlRfU0VDUkVU

🚧
Send one method per request
If a request includes both headers, the API uses X-API-Key and ignores Authorization.

When authentication fails

Missing or invalid credentials return 401 Unauthorized. Check that:

the header name is spelled exactly X-API-Key, or that the scheme is Basic;
the value has no extra spaces or line breaks;
the key has not been regenerated since you copied it.

Repeated failed attempts from the same IP address can get that address blocked for a while.

Keep your credentials secure

Call the API from your server only. Never put credentials in browser code, mobile apps or public repositories.
Store them in environment variables or a secrets manager, not in source code.
If a credential leaks, regenerate it on the API Keys page. The old value stops working immediately, so deploy the new value right away.