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Roles are a common way to group users and assign permissions to those groups. They can be used to simplify permission management, especially in larger systems where many users have similar access needs. In this guide, we’ll explore common approaches to modeling roles with OpenFGA.

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When to Use Each Approach

Before diving into implementation details, here’s a quick guide to help you choose the right approach:

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Approach 1: Relations as Roles

The simplest way to implement roles is to use directly assignable relations. They work well for roles that always exist and can be defined at development-time. Adding relations is straightforward, and you do not need to add roles very frequently. If roles are static, this is always the preferred approach.

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Example: Organization Admin Role

In the model below, we define an admin role at the organization level. Admins can edit billing details and create projects.

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Adding Users to Roles

To add users to the admin role, create a tuple like:

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Extending with Additional Roles

If later you need to add a project_admin role with permissions to view/edit projects, the model evolves to:

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Pros and Cons

✅ Advantages:
  • Simple to implement and understand
  • Fast evaluation performance
  • Clear authorization policies
  • No additional tuples needed when adding permissions
  • Role permissions are straightforward to change, regardless of scale
❌ Disadvantages:
  • Roles must be predefined in the model
  • Not suitable for user-defined roles

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Approach 2: Simple User-Defined Roles

Many applications require the flexibility for end-users to define their own custom roles, in addition to any pre-defined roles. This approach enables organizations to tailor permissions to their specific needs.

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Example: Custom Project Admin Role

With the following model, your application can support both static roles and user-defined roles:

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Setting Up Custom Roles

  1. Define role permissions by creating tuples that grant the role-specific permissions:
  1. Assign users to the role:

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Adding New Permissions

When you add new permissions to your model, existing roles don’t automatically receive them: To grant the new permission to existing roles, create additional tuples:
You do not need to add these tuples when adding the new permission. End-users will add the new permission to their custom roles when they find it appropriate.

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Pros and Cons

✅ Advantages:
  • Supports user-defined roles
  • Flexible permission assignment
  • No model changes needed for new role instances
❌ Disadvantages:
  • More complex than static relations
  • Requires additional tuples for role-permission mapping

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Approach 3: Role Assignments

The previous approach works well when custom roles are global for the organization. However, if you need roles that can be attached to different object instances with different members for each instance, you need role assignments.

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Example: Project-Specific Admin Roles

Let’s say you want a “Project Admin” role where each project can have different admins, but the role permissions remain consistent.

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Step 1: Define the Role and its Permissions

Define a role type where you list all the permissions that any role can have: A “Project Admin” role can have can_view_project and can_edit_project:

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Step 2: Assign Users to a Role on an Entity

Add a role_assignment type to assign users to the role:

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Step 3: Connect to Your Objects

Define an organization type with an admin role. Then, define a project type that links to an organization and a role_assignment. Note that we are combining a static admin role with custom role assignments. We recommend to always use static roles when they are known in advance.

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Setting Up Role Assignments

  1. Create the role assignment instance:
  1. Link the role assignment to the project:
  1. Link the project to an organization:

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Pros and Cons

✅ Advantages:
  • Maximum flexibility for instance-specific roles
  • Reusable role definitions across different objects
  • Fine-grained control over role membership
❌ Disadvantages:
  • Most complex approach to implement
  • Requires careful planning of the role hierarchy
  • More tuples needed for setup and maintenance

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Choosing the Right Approach

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Decision Tree

  1. Do you need user-defined roles?
    • No → Use Relations as Roles
    • Yes → Continue to step 2
  2. Do roles need different members per object instance?
    • No → Use Simple User-Defined Roles
    • Yes → Use Role Assignments

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Performance Considerations

  • Relations as Roles: Fastest evaluation
  • Simple User-Defined Roles: Moderate performance impact
  • Role Assignments: Highest performance impact

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Best Practices

  1. Start simple: Begin with relations as roles and evolve as needed
  2. Hybrid approach: Combine static relations for well-known roles with dynamic roles for custom ones
  3. Documentation: Clearly document your role model for your team
  4. Functional Testing: Write tests to verify your model behaves as expected
  5. Performance Testing: Test performance with realistic data volumes
Check out these related resources for more information about adopting OpenFGA.

Custom Roles Step by Step

Follow a detailed walkthrough of implementing custom roles.

Multi-tenant RBAC Example

See a complete multi-tenant role-based access control implementation.

Role Assignments Example

Explore a full role assignments implementation.
Last modified on September 28, 2026