API terms of use
These apply on top of our Terms of Service whenever you use the API.
Last updated: November 5, 2026
What the API is for
Use the API to check lists you have a lawful reason to check, such as your own customers and contacts, in line with the laws that apply to you and to the people on your lists. You are responsible for that, and for what you do with the results.
What you may not do
- Harass, stalk, threaten or track anyone, or look up someone to find out about them without a lawful reason.
- Send spam or unwanted messages using the results.
- Sell or publish the results as a data set of your own.
- Go around a rate limit or a block, for example with several accounts.
- Attack or disrupt the service. To report a security problem, see our Vulnerability Disclosure Program.
Your keys
You are responsible for your keys and for everything done with them, including what they spend. Keep them secret, and revoke one that may have been seen. Charges made with a key before you revoke it stand.
Blocking and closing
We may block a key or an account, or close either, if these terms are broken or to protect the service or other people, with or without notice. Orders already placed may still run. We may change or end the API, and we will post changes that affect your code in the Changelog.
Results and availability
Results come from checks that are best-effort, not guaranteed, and can be a recent earlier result of yours. The API may be unavailable at times, and we are not liable for what depends on it, as our Terms of Service set out.