CASL

What it is

CASL is an isomorphic authorization library that allows you to define and enforce access control rules in both the frontend and backend of your application, ensuring consistent security policies across all layers.

CASL stands out by providing an isomorphic solution, allowing developers to maintain consistent security policies across both frontend and backend environments with a flexible and type-safe approach.

When it fits — and when it doesn’t

Known weaknesses

Each one links to the public issue, changelog or docs page it came from, where we have one.

1. 01

   Steep learning curve for non-JavaScript developers

   CASL's API and documentation are heavily oriented towards JavaScript patterns, which can be challenging for developers unfamiliar with the ecosystem.

2. 02

   Limited community support and small user base

   The CASL GitHub repository has a relatively low number of stars and contributions compared to more established authorization libraries like Auth0 or Keycloak, indicating limited community engagement and slower issue resolution.

3. 03

   Performance overhead in complex rule evaluations

   CASL's dynamic rule evaluation mechanism can introduce performance bottlenecks when dealing with a large number of rules or complex predicates, especially on the frontend.

What it does well

• Isomorphic authorization for both frontend and backend

• Supports TypeScript with type-safe rules

• Flexible rule definitions using predicates and actions

• Extensive documentation and community support

Pricing

Free tier

YesOpen source — free to use

Paid from

$0

Model

Flat rate

Enterprise plan

No

Pricing not independently confirmed — check the vendor’s page.