In recent years the mobile health industry is booming. Companies like FitBit, Moves, Nike are leading this revolution. Essential idea behind these services is that you can measure the number of activities or calorie burn, calorie intake or food consumption and quality of your sleep. Since it is becoming a huge deal, naturally a lot of startups are taking advantage of it and trying to take advantage of this data. Some companies are providing integration points with these services and unifying data, some are just proxies to these API’s. Challenges for these types of startups is data unification, rate limits and user’s expectation of instant feedback. While working with multiple API’s, each one of them has a unique format that needs to be parsed and stored. Another issue that you have to solve is rate limiting. For example, if you want to get step count for a month and API provides this kind of data only on daily basis, API rate limits become an issue since data fetching for a month are 30 requests. And the user may hit the “sync” button more than once. If you want to increase rate limits, you would have to sign a contract with the data provider, which may be a tedious process. Also, consider the fact that user wants to see he’s steps immediately after he synchronizes with the provider. Sometimes providers love to change their API unannounced or somehow you may miss that fact.