The OpenHMIS API is a web-based API for collecting data and generating reports about sources and users of social services. The latest version of the API is version 3 and it is currently under development:
Although the API is still in development, there is an incomplete/unstable version of it (both server and demo client) running here.
For an example of the API in use, see the Mobile Outreach App design specification.
Our long-term goal is for the API to reflect the full data schema from the 2014 data standards from the U.S. Department of Housing and Urban Development (HUD). While the API is still fairly minimal, this schema based on the full HUD 2014 Data Standards gives an idea of what the API will eventually support, and this smaller schema gives an idea of what the API supports so far. (The latter diagram is not always kept in sync with the database or API implementations, so it may be a bit out of date.)
For more information about the HUD 2014 standards, see:
- HMIS Data Exchange Resources (pay attention only to things with "2014" or later next to them)
- 2014 HMIS Logical Model UML diagram
- HUD 2014 HMIS Data Dictionary
Note that the OpenHMIS API is intended to compatibly cover the same core API defined by the HMIS API project project. This overlap is deliberate: interoperability is a primary goal of OpenHMIS, and staying compatible with the HMIS API is how OpenHMIS ensures interoperability with HMIS clients and servers from many providers.
There have been two earlier versions of the OpenHMIS API, both of them based on the HUD 2010 data standards. Neither should be used as a basis for new development now, since they are based on HUD 2010 instead of on HUD 2014, but we list them here for reference:
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OpenHMIS API v1. This API is implemented by the deprecated_v1_api branch, and is the API currently used by the Homeless Helper application.
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OpenHMIS API v2. No clients use this version and no known servers implement it.