General requirements

Use HTTPS only.

Use asynchronous calls. This will avoid problems with loading the web page when any of the systems' pixels have technical issues.

The called URL must respond with HTTP 302 if redirection is required, or HTTP 204 or HTTP 200 if redirection is not required.

Do not respond with HTTP 4XX, HTTP 5XX, or other codes other than those specified above.

You must comply with privacy settings such as do-not-track, COPPA, GDPR, and others.