tellows API – Partnership Program
What is tellows?
- tellows is a community project operating in over 50 countries worldwide as a leading phone number resource
- Users rate phone numbers using our score model: the tellows score
- Reported numbers display how trustworthy the number is and provide helpful information for other users
- Our blacklist contains all of the negatively reported numbers
- More than 7 million users visit tellows monthly
- Numbers on tellows receive over 20.000 comments monthly
- tellows is available for desktop, smartphones and tablets
- The tellows app for real-time identification of callers is available for iOS and Android

Who uses tellows?
tellows ABC markets worldwide – differentiated by the amount of visitors and reported numbers:
- A markets are the most important tellows markets with 4.4m visits / month covering 80% of the total community; Germany, United Kingdom, Italy and France are the most important markets.
- B markets are between 40.000 and 100.000 visitors / month
- C markets contain less than 40.000 visits monthly
A markets | B markets |
Germany | United States |
Italy | Taiwan |
Indonesia | Portugal |
Brazil | South Africa |
United Kingdom | Switzerland |
France | Poland |
Spain | Japan |
Mexico | Austria |
tellows score

The tellows score is classified by our community on a scale of 1 (where 1 is trustworthy) to 9 (where 9 is untrustworthy) and entails harassment calls including aggressive advertising. To calculate the scores, tellows uses a complex algorithm to arrange individual numbers, considering several factors and the users’ opinion. Therefore, all tellows users can see from a quick glance, whether the person calling is a trustworthy caller or not.
tellows API for blacklist integration
- Phone Number
- tellows score
- Number of comments
- Number of search requests
- Caller type
- Caller name (assigned by users)
- Area (including ZIP code, city, country code)
- Comments for each phone number
- Set language for the result output
- Deeplink to phone number
- Filter results by score, country, comments or search requests
Data Lifecycle of the Blacklist
Lifespan of Numbers on the Blacklist
The API allows you to receive all relevant numbers in one request.
For more information contact us
tellows API Adapts to Your Needs
The Live API provides real-time caller protection with live data, which includes all details about a phone number. Once the blacklist is downloaded, the Live API can be used to gather further information for every number on the blacklist with all possible caller names, caller types or comments etc. This service can be integrated into lookup services or widgets that need to provide live-data.
The Reputation API / Company API allows companies to track the caller history and customer satisfaction of company operatives. It is possible to target certain keywords that are assocciated with the company or track a list of numbers that are assigned to the company. Monitor the caller quality with the help of the tellows ratings. This service is especially designed for companies operating call centers or sales employees performing outbound calls. With the help of the tellows data, the service quality and reputation can be improved.
Add Comments to tellows with our Live API. In order to increase the database and let other users benefit from your solutions, you can send back ratings to tellows with your built application or software and help expand the tellows database. Comments and ratings reported by your software or application will be featured with your brand name.
More information about the tellows API on Medium
tellows Shop Products & Partners
tellows API Key for Developers
Thanks to the tellows API Key, programmers and telecommunications device developers are now able to query the tellows database through a telecommunications device (e.g. Asterisk). Regardless of whether you want to use the API Key as a real time block list or just to identify calls. Thanks to the great interest for the tellows score lists, we now want to offer the possibility of a real-time caller protection. With the help of the API Key and a suitable phone system this is no longer a problem.
For private usage the Live API key can be obtained in the tellows shop. Feel free to present us your developments in order to get featured on our website and earn yourself a free API-key for a limited time.
For small and medium sized enterprises we offer a API key accoring to the amount of channels in use. Visit our shop for more information.