The Human Services Data Specification (HSDS) is an open data standard, stewarded by Open Referral, for describing health, human, and social services and where to find them. It defines a common tabular/relational model for organizations, the services they provide, and the locations where those services are delivered, so that community resource directories can be published, exchanged, and kept current in a machine-readable way.
Human Services Data Specification (HSDS)
The Human Services Data Specification (HSDS) is the data model at the heart of Open Referral — a community effort to make information about health, human, and social services as open and reusable as any other public data. HSDS gives cities, nonprofits, and 211/information-and-referral providers a shared way to describe what services exist, who provides them, and where to get them.
- Common data model - Organizations, services, locations, contacts, and the taxonomies that classify them, expressed as a clear relational/tabular schema.
- Publishable and exchangeable - A directory of community resources can be exported, shared, and merged across agencies instead of being locked inside a single system.
- Companion API - HSDS is the data specification; the Human Services Data API (HSDA) is the paired interface standard for querying and updating it over HTTP.
- Open governance - Stewarded in the open by Open Referral, with real municipal and nonprofit implementations behind it.
I spent a meaningful chunk of my API work helping define OpenAPI-based interfaces for HSDS and building out the surrounding API definitions — it remains one of the clearest examples of why a shared, machine-readable data standard matters for the public good, and why an API on top of that standard is what actually makes the data usable.
Referenced on the API Evangelist blog
Where this standard shows up across sixteen years of my writing at apievangelist.com — how it fits into API design, governance, and the agentic turn.
