With Situm Rest API you can retrieve all your geo-information of your building to integrate it with third-party solutions, including floor plans, POIs, events, and get all the historial of users positions. You can also generate all the analytics that you need according to your use case. The documentation and more information can be found in Developers in the following link:
http://developers.situm.es/pages/rest/
1. The first step is create an account in our dashboard: https://dashboard.situm.com/
More info - How to register at Situm Dashboard
2. Then, generate an API Key
Log into your dashboard account and generate your API Key in Profile 
3. Download the situm_public_api.yaml file in Developers
4. Use Swagger
You can find more information about getting started with Swagger in the following link:
5. Now, to start using our resources, you need to be able to perform the Authentication and Authorization processes:
Authentication & Authorization