Registry stack documentation: machine-readable Markdown.
Index of all pages: https://docs.registrystack.org/llms.txt
Full corpus: https://docs.registrystack.org/llms-full.txt

# Integration patterns

> How Registry Stack wires in behind exchange layers, workflow engines, wallets, and domain registry platforms, and the standards each surface speaks.

Registry Stack is the registry-facing surface that sits behind systems already in a delivery
stack. This page describes the technical wiring for each neighbor: what the neighbor owns, what
Registry Stack adds, and the conditions under which a Registry Stack surface belongs in the path.
For where the registry family sits relative to the wider ecosystem as a product positioning, see
the marketing [ecosystem page](https://registrystack.org/ecosystem/).

## Country evidence mesh

At country scale, the same pattern can sit next to several domain platforms.
Clinical health systems can expose bounded facts through a FHIR API, public-health program systems
can be reached through DHIS2 and OpenFn, and social protection, agriculture, education, and civil
registration systems can keep their own authoritative stores.
Registry Notary instances return configured claims to a social protection management information
system and citizen-facing service channels without turning those consumers into raw-record readers.

{/* SVG diagram. Essential labels are restated in the paragraph before the figure. */}
<figure>
  <img src="../../images/registry-country-evidence-mesh.svg"
       alt="Country evidence mesh: civil registration, clinical health over FHIR API,
            public health through DHIS2 and OpenFn, social protection, agriculture, and
            education registries each keep their source systems. Registry Notary add-ons
            return signed minimized attestations to a social protection MIS and citizen
            service channels. The consuming systems receive claims, not full source rows." />
</figure>

## Domain registry platforms

Examples: [OpenCRVS](https://www.opencrvs.org/) (civil registration), [OpenSPP](https://openspp.org/)
(social-protection household and programme management), [DHIS2](https://dhis2.org/) (health
management information), [OpenIMIS](https://openimis.org/) (health insurance information).

These platforms own storage, business rules, correction workflows, user interfaces, and a runtime
API for their domain.
Registry Stack adds standardized metadata description, scoped read-only routes over source data,
configured evidence responses, and tamper-evident audit records.

Wire Registry Stack in alongside a domain platform when:

- The platform does not yet publish DCAT/BRegDCAT-AP catalogs or CPSV-AP service descriptions.
- Callers need evidence-shaped responses (predicate, redacted, selected value) rather than full
  records.
- A read path is needed for callers that must not be granted direct database access.

## Workflow engines

Examples: [OpenFn](https://www.openfn.org/) (cross-system orchestration popular in humanitarian and
government data flows), [Camunda](https://camunda.com/), [Flowable](https://www.flowable.com/).

Workflow engines own process state, task assignment, timers, branching, retries, escalation, and
history.
Registry Stack adds a stable registry contract that workflow steps can call, without learning
source tables, raw SQL, or full records.

Wire Registry Stack in alongside a workflow engine when:

- A workflow step needs an authoritative registry fact (status, predicate, selected value).
- A workflow step needs an evidence artifact or credential rather than an internal service result.
- Generated workflow connectors must not depend on source schema details.

## Exchange layers

Examples: [X-Road](https://x-road.global/), [OpenFn](https://www.openfn.org/) (when used as the
cross-institution data flow), GovStack-style reference exchanges.

Exchange layers own participant onboarding, message transport, mutual trust, routing, addressing,
and cross-institution policy.
Registry Stack adds the registry-facing surface that sits behind the exchange layer: what entities
exist, which fields are exposed, what evidence can be requested.

Wire Registry Stack in behind an exchange layer when:

- The exchange layer handles network trust but the registry endpoint still needs route-level
  scopes, field projection, and source-specific access controls.
- An exchange-forwarded request needs a configured evidence response rather than a copied record.

## Wallets

Examples: SD-JWT VC wallets, OID4VCI-compatible wallets.

Wallets own key management, credential storage, holder consent, and presentation to relying
parties.
Registry Stack adds the server-side issuance path: claim evaluation against registry data, plus
the metadata describing what a registry-backed issuer offers.

Wire Registry Stack in alongside a wallet when:

- A registry-backed issuer needs to produce SD-JWT VC credentials or an OID4VCI issuance flow.
- An evidence offering needs to be discoverable before integration begins.

## Public-service platforms

Examples: citizen portals, casework systems, service catalogue platforms.

These platforms own the user journey: forms, case queues, notifications, payments, channels.
Registry Stack adds the narrow registry-facing surface those journeys can call: entity routes,
evidence responses, scoped metadata, and audit records.

Wire Registry Stack in alongside a service platform when:

- A service platform needs a registry answer during delivery but must not pull the full record.
- A service catalogue needs to discover an evidence offering before integration.

## Standards each surface speaks

Each integration surface involves a different set of standards.
The claim level differs per standard (some surfaces emit a standard, others map to or
compare against it); the [standards register](../../reference/standards/) is the
authoritative list of claim levels and per-project evidence.

| Integration surface | Relevant standards |
| --- | --- |
| Catalog and service discovery (Registry Manifest, Relay metadata routes) | DCAT, BRegDCAT-AP, CPSV-AP, OGC API Records, SHACL, JSON Schema, ODRL |
| Protected data routes (Registry Relay) | OpenAPI, SP-DCI, GovStack Digital Registries, OGC API Features |
| Evidence and credentials (Registry Notary) | OpenAPI, CCCEV, SD-JWT VC, OID4VCI, W3C DID |

## Next

- [Architecture overview](../architecture/)
- [Standards register](../../reference/standards/)
- [Boundaries and map](../../map/boundaries-and-map/)