PlanMill first launched an API in 2009, as one of the first in similar business applications to have an API, definitely the first in Finland. Since then APIs have developed with huge leaps and creating an API has become both art and science. The question “Do you have an API for that?” has become as common place as “Do you have an app for that?”.

PlanMill has been around for 10+ years and has wide range of functionality as a professional services automation system (PSA for the Americans, ERP for us Finns).

Developing user interfaces with new technologies and mobile requirements in mind, requires an API that covers almost every function in the company, legal accounting and direct exchange with banks excluded.

As the early-adopters, we did lots of mistakes in our first API. We also did a lot of good things and have customers and partners still using the first version after 7 years.

Now we are approaching one critical step in the ongoing saga and getting ready to say goodbye to the old API. I would like to share some insights and practical questions and solutions through our case about documentation, feedback from customers and above all: Eating our own dog food by using the new API with both new and old UI technologies and integration cases.