AuthZEN API (Experimental)

OpenFGA implements the AuthZEN specification, a standard API for authorization interoperability defined by the OpenID AuthZEN working group. This allows you to use OpenFGA as an AuthZEN-compliant Policy Decision Point (PDP).

We recommend that you use the native API when integrating your application with OpenFGA, and you use AuthZEN when you are integrating an AuthZEN-compatible product like an API/MCP Gateway, or an Identity Provider. It's not possible to implement OpenFGA only with AuthZEN endpoints, as it does not specify endpoints to Write and Read.

You can validate the implementation using the AuthZEN interop scenarios for OpenFGA, which cover the standard AuthZEN interop scenarios.

Experimental

The AuthZEN API is experimental and must be explicitly enabled. The API surface may change in future releases.

Enabling AuthZEN

To enable the AuthZEN endpoints, start the server with the authzen experimental flag:

openfga run --experimentals=authzen

Or via environment variable:

OPENFGA_EXPERIMENTALS=authzen openfga run

Or in a configuration file:

experimentals:
  - authzen

All AuthZEN endpoints return an Unimplemented error if the experimental flag is not enabled.

Endpoints

All AuthZEN endpoints are scoped to a store. Evaluation and search endpoints are available under /stores/{store_id}/access/v1/. The Get Configuration (discovery) endpoint uses a different path: /.well-known/authzen-configuration/{store_id}.

Endpoint	Method	Path	Description
Evaluation	POST	/stores/{store_id}/access/v1/evaluation	Check if a subject can perform an action on a resource
Evaluations	POST	/stores/{store_id}/access/v1/evaluations	Batch check multiple authorization decisions
Subject Search	POST	/stores/{store_id}/access/v1/search/subject	Find subjects with access to a resource
Resource Search	POST	/stores/{store_id}/access/v1/search/resource	Find resources a subject can access
Action Search	POST	/stores/{store_id}/access/v1/search/action	Find actions a subject can perform on a resource
Get Configuration	GET	/.well-known/authzen-configuration/{store_id}	PDP discovery and endpoint URLs

Specifying an Authorization Model

By default, AuthZEN endpoints use the latest authorization model in the store. To pin requests to a specific model version, pass the Openfga-Authorization-Model-Id header:

POST /stores/01G5JAVJ41T49E9TT3SKVS7X1J/access/v1/evaluation
Openfga-Authorization-Model-Id: 01G50QVV17PECNVAHX1GG4Y5NC
Content-Type: application/json

{
  "subject": {"type": "user", "id": "anne"},
  "action": {"name": "reader"},
  "resource": {"type": "document", "id": "roadmap"}
}

This header is optional and works with all AuthZEN endpoints.

Evaluation

The Evaluation endpoint determines whether a subject is authorized to perform an action on a resource. It maps to the OpenFGA Check endpoint.

Request:

POST /stores/{store_id}/access/v1/evaluation

{
  "subject": {"type": "user", "id": "anne"},
  "action": {"name": "reader"},
  "resource": {"type": "document", "id": "roadmap"}
}

Response:

{
  "decision": true
}

The action.name must exactly match a relation defined on the resource type in your authorization model. For example, {"name": "reader"} checks the reader relation on the resource type.

You can also pass ABAC attributes and additional context — see ABAC Support below.

ABAC Support

Properties on the subject, resource, and action are automatically merged into the evaluation context with prefixes, enabling Attribute-Based Access Control (ABAC) with conditions:

• Subject properties are prefixed with subject_
• Resource properties are prefixed with resource_
• Action properties are prefixed with action_

{
  "subject": {
    "type": "user",
    "id": "anne",
    "properties": {"department": "engineering", "clearance_level": 3}
  },
  "action": {"name": "reader"},
  "resource": {
    "type": "document",
    "id": "secret-project",
    "properties": {"classification": "confidential", "required_clearance": 2}
  }
}

The merged context will contain subject_department, subject_clearance_level, resource_classification, and resource_required_clearance.

You can also pass context directly using the context field:

{
  "subject": {"type": "user", "id": "bob"},
  "action": {"name": "reader"},
  "resource": {"type": "system", "id": "production"},
  "context": {
    "current_time": "2024-01-15T14:30:00Z",
    "ip_address": "192.168.1.100"
  }
}

Evaluations

The Evaluations endpoint performs batch authorization checks in a single request. It supports request-level defaults for subject, action, resource, and context that can be overridden per evaluation item.

Request:

POST /stores/{store_id}/access/v1/evaluations

{
  "subject": {"type": "user", "id": "anne"},
  "resource": {"type": "document", "id": "roadmap"},
  "evaluations": [
    {"action": {"name": "reader"}},
    {"action": {"name": "writer"}},
    {"action": {"name": "owner"}}
  ]
}

Response:

{
  "evaluations": [
    {"decision": true},
    {"decision": false},
    {"decision": false}
  ]
}

Overriding Defaults

Each evaluation item can override the request-level defaults:

{
  "subject": {"type": "user", "id": "anne"},
  "action": {"name": "reader"},
  "evaluations": [
    {"resource": {"type": "document", "id": "doc1"}},
    {"resource": {"type": "document", "id": "doc2"}},
    {"resource": {"type": "folder", "id": "folder1"}}
  ]
}

Evaluation Semantics

The options.evaluations_semantic field controls how evaluations are processed:

Semantic	Description
execute_all (default)	Execute all evaluations and return all results
deny_on_first_deny	Stop on first deny decision
permit_on_first_permit	Stop on first permit decision

When using deny_on_first_deny or permit_on_first_permit, the response may contain fewer items than the number of evaluations in the request because processing short-circuits when the condition is met.

{
  "subject": {"type": "user", "id": "anne"},
  "resource": {"type": "document", "id": "roadmap"},
  "evaluations": [
    {"action": {"name": "reader"}},
    {"action": {"name": "writer"}}
  ],
  "options": {
    "evaluations_semantic": "permit_on_first_permit"
  }
}

If reader is permitted, only one evaluation response is returned.

If evaluations is omitted or empty, OpenFGA treats the request like a single Evaluation using the top-level subject, action, resource, and optional context, and returns a single-item evaluations array.

Subject Search

The Subject Search endpoint returns all subjects that have a specific action (relation) on a given resource. It maps to the OpenFGA ListUsers endpoint.

This answers questions like "Who can read this document?"

Request:

POST /stores/{store_id}/access/v1/search/subject

{
  "resource": {"type": "document", "id": "roadmap"},
  "action": {"name": "reader"},
  "subject": {"type": "user"}
}

Response:

{
  "results": [
    {"type": "user", "id": "anne"},
    {"type": "user", "id": "bob"}
  ]
}

The subject field is required and must include type. If subject.id is provided, it is ignored (per AuthZEN Subject Search semantics).

note

Pagination is not currently supported for search endpoints. See Implementation Notes for details.

Resource Search

The Resource Search endpoint returns all resources of a given type that a subject has a specific action (relation) on. It maps to the OpenFGA ListObjects endpoint.

This answers questions like "What documents can Anne read?"

Request:

POST /stores/{store_id}/access/v1/search/resource

{
  "subject": {"type": "user", "id": "anne"},
  "action": {"name": "reader"},
  "resource": {"type": "document"}
}

Response:

{
  "results": [
    {"type": "document", "id": "roadmap"},
    {"type": "document", "id": "budget-2024"}
  ]
}

The resource field is required and must include type. If resource.id is provided, it is ignored (per AuthZEN Resource Search semantics).

note

Pagination is not currently supported for search endpoints. See Implementation Notes for details.

Action Search

The Action Search endpoint returns all actions (relations) that a subject can perform on a specific resource. This is useful for building dynamic UIs that show only the actions a user is permitted to perform.

This answers questions like "What can Anne do with this document?"

Request:

POST /stores/{store_id}/access/v1/search/action

{
  "subject": {"type": "user", "id": "anne"},
  "resource": {"type": "document", "id": "roadmap"}
}

Response:

{
  "results": [
    {"name": "reader"},
    {"name": "writer"}
  ]
}

Action Search evaluates all relations defined on the resource type in your authorization model (including computed and inherited relations) and returns those where the subject has access. The checks are performed using the same logic as the Evaluation endpoint.

note

Pagination is not currently supported for search endpoints. See Implementation Notes for details.

Get Configuration

The Get Configuration endpoint returns PDP discovery information per AuthZEN specification section 9.2.2. It provides the PDP identifier URL and absolute endpoint URLs for that store.

Each store has its own discovery endpoint.

Request:

GET /.well-known/authzen-configuration/{store_id}

Response:

{
  "policy_decision_point": "https://example.com/stores/01G5JAVJ41T49E9TT3SKVS7X1J",
  "access_evaluation_endpoint": "https://example.com/stores/01G5JAVJ41T49E9TT3SKVS7X1J/access/v1/evaluation",
  "access_evaluations_endpoint": "https://example.com/stores/01G5JAVJ41T49E9TT3SKVS7X1J/access/v1/evaluations",
  "search_subject_endpoint": "https://example.com/stores/01G5JAVJ41T49E9TT3SKVS7X1J/access/v1/search/subject",
  "search_resource_endpoint": "https://example.com/stores/01G5JAVJ41T49E9TT3SKVS7X1J/access/v1/search/resource",
  "search_action_endpoint": "https://example.com/stores/01G5JAVJ41T49E9TT3SKVS7X1J/access/v1/search/action"
}

Mapping AuthZEN to OpenFGA Concepts

The AuthZEN API uses its own terminology that maps directly to OpenFGA concepts:

AuthZEN	OpenFGA	Description
Subject (type + id)	User (type:id)	The entity requesting access
Resource (type + id)	Object (type:id)	The entity being accessed
Action (name)	Relation	The operation being performed
Evaluation	Check	Single authorization decision
Evaluations	BatchCheck	Batch authorization decisions
Subject Search	ListUsers	Find users with access to an object
Resource Search	ListObjects	Find objects a user can access
Properties	Conditions / Context	ABAC attributes for conditional evaluation

Implementation Notes

The OpenFGA AuthZEN implementation follows the AuthZEN Authorization API 1.0 specification with a few adaptations for multi-tenancy. This section documents the key differences.

Multi-tenant URL paths

The AuthZEN spec defines endpoints at /access/v1/evaluation, /access/v1/evaluations, etc. Because OpenFGA is multi-tenant, all endpoints are scoped under /stores/{store_id}/:

AuthZEN Spec	OpenFGA
/access/v1/evaluation	/stores/{store_id}/access/v1/evaluation
/access/v1/evaluations	/stores/{store_id}/access/v1/evaluations
/access/v1/search/subject	/stores/{store_id}/access/v1/search/subject
/access/v1/search/resource	/stores/{store_id}/access/v1/search/resource
/access/v1/search/action	/stores/{store_id}/access/v1/search/action
/.well-known/authzen-configuration	/.well-known/authzen-configuration/{store_id}

Response context fields

The spec allows an optional context object in evaluation responses to convey additional information such as reasons, obligations, or UI hints. Per the spec, context is an arbitrary JSON object whose format is implementation-defined.

The current implementation:

• Does not populate context in successful evaluation responses
• Does populate context.error (with status and message) for individual failures in batch evaluations:

{
  "decision": false,
  "context": {
    "error": {
      "status": 500,
      "message": "missing result for evaluation 0"
    }
  }
}

Identifier validation constraints

The AuthZEN spec models subject.type, subject.id, resource.type, resource.id, and action.name as strings. OpenFGA applies additional OpenFGA identifier constraints (pattern and length checks). Constraints are field-specific.

Pagination

The spec defines optional pagination for search endpoints using opaque continuation tokens (next_token). The current implementation does not support pagination — all matching results are returned in a single response. The page field in search requests is accepted but ignored.

PDP metadata fields

The AuthZEN metadata model defines optional fields such as capabilities and signed_metadata. The current implementation returns endpoint metadata fields but does not expose signed_metadata and does not currently advertise capability URNs.

Authorization model selection extension

The AuthZEN spec does not define a standard way to pin requests to a specific model version. OpenFGA adds Openfga-Authorization-Model-Id as an OpenFGA-specific request header extension.

X-Request-ID header

The spec RECOMMENDS that PEPs include an X-Request-ID header in requests and that PDPs echo it back in responses. OpenFGA returns an X-Request-ID header in all responses but does not currently echo back client-provided request IDs.

Contextual Tuples

The AuthZEN spec does not define a concept equivalent to Contextual Tuples. If your authorization model depends on contextual tuples for certain checks, you must use the native OpenFGA API for those checks.

Related Sections

Learn more about the concepts and APIs used by the AuthZEN integration.

Relationship Queries

Learn about the underlying Check, ListObjects, and ListUsers APIs.

• More

Conditions

Learn how to use conditions for attribute-based access control.

• More

Contextual Tuples

Learn about temporary relationship tuples for request-scoped authorization.

• More