Pundit

Minimal, object-oriented authorization library for Ruby on Rails. Pundit uses plain Ruby policy classes — one per model — to answer 'can this user do this action on this object?' Each policy is a PORO (Plain Old Ruby Object) with methods like create?, update?, destroy? that receive the current user and record. Policies are easily tested in isolation. Pairs with Devise for authentication + authorization.

Evaluated Mar 07, 2026 (0d ago) v2.x
Homepage ↗ Repo ↗ Developer Tools ruby rails authorization policy rbac permissions security
⚙ Agent Friendliness
67
/ 100
Can an agent use this?
🔒 Security
92
/ 100
Is it safe for agents?
⚡ Reliability
88
/ 100
Does it work consistently?

Score Breakdown

⚙ Agent Friendliness

MCP Quality
--
Documentation
88
Error Messages
85
Auth Simplicity
92
Rate Limits
95

🔒 Security

TLS Enforcement
100
Auth Strength
90
Scope Granularity
88
Dep. Hygiene
90
Secret Handling
92

Policy objects are pure Ruby — easy to audit. Separation of authentication and authorization. Policy scopes prevent data leakage in list endpoints. No external network calls.

⚡ Reliability

Uptime/SLA
90
Version Stability
88
Breaking Changes
85
Error Recovery
88
AF Security Reliability

Best When

You're building Rails apps with resource-level permissions and want simple, testable policy objects without the complexity of a full authorization framework.

Avoid When

You need complex hierarchical role permissions or ABAC rules — Pundit's simplicity becomes a limitation for complex authorization schemes. CanCanCan offers more rule composition.

Use Cases

  • Implement role-based access control in Rails agent backends using Pundit policy classes that define what each user role can do to each resource
  • Authorize agent API actions by calling authorize(@record) in controllers — Pundit raises NotAuthorizedError for unauthorized actions that can be rescued globally
  • Scope database queries to authorized records using Pundit policy scopes — ensures agents only see data they're permitted to access
  • Test authorization logic in isolation using RSpec unit tests on policy classes without needing full controller/request test setup
  • Build admin interfaces with fine-grained field-level authorization — Pundit policies can check individual attribute updates in permitted_attributes

Not For

  • Non-Rails Ruby apps needing authorization — Action Policy is Pundit's successor with better performance; Rack-level apps should use cancancan
  • Attribute-based access control (ABAC) with complex rule engines — Pundit is simple policy objects; use OPA or Casbin for complex policy engines
  • Non-Ruby stacks — Casbin (multi-language), OPA (policy engine), or built-in framework auth for other stacks

Interface

REST API
No
GraphQL
No
gRPC
No
MCP Server
No
SDK
Yes
Webhooks
No

Authentication

Methods: none
OAuth: No Scopes: No

Pundit is an authorization library (what can you do?), not authentication (who are you?). Pair with Devise for authentication. Pundit receives current_user from the controller context.

Pricing

Model: open_source
Free tier: Yes
Requires CC: No

Pundit is MIT licensed, maintained by Varvet. Free for all use.

Agent Metadata

Pagination
none
Idempotent
Full
Retry Guidance
Not documented

Known Gotchas

  • authorize must be called explicitly — Pundit does not auto-authorize; after_action verify_authorized is recommended to catch missing authorize calls in controllers
  • policy_scope must be used for index/list actions — without policy_scope, all records are returned regardless of authorization; a common security bug in new Pundit integrations
  • current_user must be accessible — Pundit calls current_user in the controller; if authentication middleware hasn't run or current_user returns nil, all policies receive nil user
  • Pundit policies must be named after models — ArticlePolicy for Article model; custom naming requires overriding policy_class; mismatch causes Pundit::NotDefinedError
  • permitted_attributes for strong parameters is per-user-role — building dynamic permitted params requires policy#permitted_attributes to check user.role; easy to miss edge cases
  • Headless/API authorization failures return 403 but Pundit's rescue_from default renders HTML — API applications must customize the rescue_from handler to return JSON 403 responses

Alternatives

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Scores are editorial opinions as of 2026-03-07.

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