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In this guide you will learn the uses of and limitations for the Check, Read, Expand, ListObjects and ListUsers API endpoints.

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Before you start

In order to understand this guide correctly you must be familiar with some Auth0 FGA Concepts and know how to develop the things that we will list below.

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Check

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What is it for?

The Check API is an API endpoint that returns whether the user has a certain relationship with an object. Auth0 FGA will resolve all prerequisite relationships to establish whether a relationship exists.

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When to use?

Check can be called if you need to establish whether a particular user has a specific relationship with a particular object. For example, you can call check to determine whether bob has a reader relationship with document:planning. The Auth0 FGA API will return true because there is an implied relationship as
  • every writer is also a reader
  • bob is a writer for document:planning

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Limits

Check out the request rate limits for your plan.

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Caveats and when not to use it

Check is designed to answer the question “Does user:X have relationship Y with object:Z?”. It is not designed to answer the following questions:
  • “Who has relationship Y with object:Z?”
  • “What are the objects that userX has relationship Y with?”
  • “Why does user:X have relationship Y with object:Z?”

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Batch Check

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What is it for?

The Batch Check API is an API endpoint that allows you to check multiple user-object-relationship combinations in a single request.

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When to use?

Batching authorization checks together in a single request significantly reduces overall network latency. Two scenarios are common to use Batch Check:
  1. When determining if the user has access to a list of objects (such as Option 1 in Search with Permissions), filter and sort on your database, then call /batch-check. Repeat to perform pagination.
  2. When determining fields on a web page the user has access to, call /batch-check for every relation necessary to show/hide each field.
For example, you can call Batch Check to determine whether bob has can_view_name, can_view_dob, and can_view_ssn relationships with patient_record:1. The Auth0 FGA API will return true depending on the level of access assigned to that user and the implied relationships inherited in the authorization model.

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Caveats and when not to use it

If you are making less than 10 checks, it may be faster to call the Check API in parallel instead of Batch Check.

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Read

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What Is It For?

The Read API is an API endpoint that returns the relationship tuples that are stored in the system that satisfy a query.

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When to use?

Read can be called if you need to get all the stored relationship tuples that relate:
  1. user + relation + object
  2. user + relation + object type
  3. user + object with any relation
  4. user + object type with any relation
  5. relation + object for any user
  6. object with any user and relation
  7. all with any user, relation, or object
For example, to query if bob has a writer relationship on document:planning (essentially finding out if a tuple exists), one can ask For example, to query all the stored relationship tuples bob has a writer relationship with on type document:, one can ask For example, to query all the stored relationship tuples bob has on type document:planning, one can ask For example, to query all the stored relationship tuples bob has on object type document:, one can ask For example, to query all the stored relationship tuples which have the writer relation on object document:planning, one can ask For example, to query all the stored relationship tuples for object document:planning, one can ask

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7. Read all tuples for any user, relation, or object

For example, to query all stored relationship tuples, one can ask

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Limits

Check out the request rate limits for your plan.

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Caveats and when not to use it

The Read API will only return all the stored relationships that match the query specification. It does not expand or traverse the graph by taking the authorization model into account. For example, if you specify that writers are viewers in the authorization model, the Read API will ignore that and it will return tuples where a user is a viewer if and only if the (user_id, "viewer", object_type:object_id) relationship tuple exists in the system. In the following case, although all writers have reader relationships for document objects and bob is a writer for document:planning, if you query for all objects that bob has reader relationships, it will not return document:planning.
Although bob is a writer to document:planning and every writer is also a reader, the Read API will return an empty list because there are no stored relationship tuples that relate bob to document:planning as reader.

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Expand

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What is it for?

The Expand API returns all users (including users and usersets) that have a specific relationship with an object. The response is represented as a tree of users or usersets. To build the full graph of access, you would need to recursively call expand on the leaves returned from the previous expand call.

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When to use?

Expand is used for debugging and to understand why a user has a particular relationship with a specific object. For example, to understand why bob can have a reader relationship with document:planning, one could first call The result of this call will be like
The returned tree will contain writer, for which we will call The result of this call will be like
From there, we will learn that
  • those related to document:planning as reader are all those who are related to that document as writer
  • bob is related to document:planning as writer

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Limits

Check out the request rate limits for your plan.

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ListObjects

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What is it for?

The ListObjects API is an API endpoint that returns the list of all the objects of a particular type that a specific user has a specific relationship with. It provides a solution to the Search with Permissions (Option 3) use case for access-aware filtering on small object collections.

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When to use?

Use the ListObjects API to get what objects a user can see based on the relationships they have. See Search with Permissions for more guidance. There’s two variations of the List Objects API.
  • The standard version, which waits until all results are ready and sends them in one response.
  • The streaming version, which should be used if you want the individual results as soon as they become available.

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Limits

Check out the request rate limits for your plan.

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Caveats

ListObjects will return the results found within the time allotted (3s).

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ListUsers

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What is it for?

The ListUsers API is an API endpoint that that returns all users of a given type that have a specified relationship with an object.

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When to use?

Use the ListUsers API to get which users have a relation to a specific object.

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Caveats

ListUsers will return the results found within the time allotted (3s).

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Summary

Check out this additional content for more information on how to query relationships.