July 12, 2011

In Search Of: API Metrics - Total Number of Developers


Sharing developer metrics is a great way to represent success and activity around your API. Many popular API platforms measure and announce their developer metrics regularly. Twitter announced yesterday it now serves 750K developers who have built 1M applications with their API. PayPal talked about its 1.5K apps and 60K PayPal X platform developers last month. Foursquare just last week shared that its API has grown to more than 10K registered developers.

Reported numbers from successful API platforms are a useful yardstick. Don't let them distract you from measuring the unique value of your own API. By their nature, reported numbers tend to be the variety that naturally chart up and to the right -- even better when they are more so than your competition. Sometimes concentrating on "getting bigger" every month can disguise important trends and value. By measuring developer metrics for your own API, your product, engineering teams and your company executives will be able to focus on where value-seeking developers are succeeding and contributing to your business.

In this series, we'll break down the top three most commonly reported developer metrics to get at the value of bigger versus better. Remember, companies may opt to report 'bigger' for various reasons, but it may be even more important in the long run to actively measure and monitor 'better'.

Total number of Developers
Many developer programs report the total number of registrations for their API program as their number of developers. Unfortunately, affiliate spammers and bots can artificially inflate the number of registered developers if you don't have a strong CAPTCHA or email validation system as part of your registration. Many folks who don't build anything with APIs register to get newsletters or marketing updates. We recommend programs attempt to more accurately track their developers using API registration numbers, then further qualifying the number to see if the registrant made the additional effort of retrieving API keys.

  • Bigger: Total developers = all unique registrations to your API
  • Better: Total developers = all unique registrations to your API + at least one API key retrieved


Retrieving API keys is not generally something bots, affiliate spammers or people who don't build applications do, because there is no additional value spending time to do so. This simple qualification can help you more closely approximate the number of actual developers registered for your API. This helps you to focus on the right users.

Next up: measuring total number of applications to get at developer adoption and activity in your API ecosystem.