FREE DNC LIST · RESOURCE GUIDE
DNC lookup API for your application
Use the API when your application needs to submit phone-number checks or process contact files programmatically. API access is available with Business VIP or Enterprise VIP.
Choose an integration
| Task | Endpoint | Input |
|---|---|---|
| Check one number | POST /api_number.php | JSON with a phone_number field |
| Process a contact file | POST /api_process.php | Multipart file upload and a zero-based column_index |
Get started
- Create an account or sign in.
- Review eligible plans on the membership page.
- Open your API dashboard and activate a key.
- Follow the authenticated documentation for request examples, response fields, and download behavior.
Keep credentials on your server
Send the key in an Authorization: Bearer header. The service also accepts an X-API-Key header. Keep production keys out of browser JavaScript, public repositories, URLs, and screenshots. The API dashboard provides key rotation if a key needs to be replaced.
Interpret a successful lookup
The single-number response includes a success flag, the phone number, an on_dnc_list value, and a readable status. Check that the request succeeded before interpreting the match field. A timeout, authentication error, or unavailable service must not be treated as a negative DNC result.
Normalize and validate numbers before submission. Keep your own processing records so you can distinguish completed checks from requests that need another attempt. If you retry a file-processing request, first establish whether the previous request completed to avoid duplicate work.
Plan your file workflow
Bulk requests accept CSV, XLS, and XLSX. Select the phone-number column by its zero-based index: the first column is 0, the second is 1. Follow the download instructions in your account's API documentation, then inspect the output and reconcile its rows with the input file. See our bulk scrubbing guide for supported inputs and skipped-row behavior.
Know what the API checks
The API compares numbers with the site's active DNC dataset. It does not identify a number's owner, establish consent, or provide a blanket decision about whether a call is allowed. Review the result interpretation guide and your organization's own requirements.
Questions about access or integration? Email [email protected]. Do not include your API key or a full contact list in an initial support message.
Ready to check your numbers?
Use the single-number checker or upload your CSV or Excel file.
Open the DNC checker