Answer
A fact or status
Use Evidence Gateway when the service needs one predefined fact such as active, enrolled, or an age band.
Use cases
Decide what each service actually needs to receive.
A service may need one signed answer or several selected fields from a registry. Registry Stack supports both while the source records stay with the registry owner.
Two types of response
Choose a signed answer or selected data.
Data
Selected data or agreed fields
Use Protected Registry APIs when the service needs specific fields for its own work and the registry owner agrees.
Different services, different information
One registry can support several services without sharing every field.
Different services can receive different answers from the same source record. Each request uses the agreement for that service and purpose.
One registry record can support different services
Public-service examples
How each type of response works in practice.
Civil registration
A service needs the person’s age band, not their date of birth.
Evidence Gateway
What is returned
Return a clear answer such as “18-64,” calculated from the civil register.
What stays at the source
Date of birth and the rest of the civil-registration record stay with the authority.
Social protection
A school meal program needs to know whether a household is enrolled.
Evidence Gateway
What is returned
Return the current enrollment status agreed by the social registry owner.
What stays at the source
The household case file, income details, and payment history are not returned.
Business registration
A procurement service needs to check whether a supplier is actively registered.
Evidence Gateway
What is returned
Return a signed active or inactive answer tied to the business number.
What stays at the source
Filing history, addresses, and ownership records stay in the business register.
Farmer support
A subsidy program needs both registration status and farm size.
Protected Registry APIs
What is returned
Return the agreed fields, such as registered status and 2.5 hectares.
What stays at the source
Plot coordinates, household members, crop history, and financial records are not returned.
Residence verification
A service needs the person’s residence region, not their full address or household record.
Evidence Gateway
What is returned
Return a signed region value defined by the registry owner for the approved purpose.
What stays at the source
The street address, household members, and rest of the source record stay with the authority.
A registry in a spreadsheet
A partner service needs a few fields from an XLSX or CSV source that is currently shared by email.
Protected Registry APIs
What is returned
Provide read-only access to agreed fields through a documented API.
What stays at the source
The source file, database credentials, and unrelated rows are not distributed to the partner.
AI-assisted services
AI-assisted services follow the same access rules as other services.
If a public service uses AI to guide a person or caseworker, it can use the same configured Registry Stack interface as any other service. The usual identity, purpose, and request checks still apply. The AI does not receive direct access to the source or special permission to query it.
Registry Stack is not an eligibility decision maker, an approval console, or general permission for an AI system to query registries. A model cannot use it to invent a new registry question or choose a different person.