Authorization Policy-as-Code Engines

Casbin is an authorization library that provides a model-based engine for enforcing access control across diverse application environments. It decouples authorization logic from application code by using a configuration-driven approach, allowing developers to define access rules and evaluation logic independently. The system supports a wide range of access control models, including role-based, attribute-based, and relationship-based patterns, which are evaluated at runtime to determine if a subject is permitted to perform an action on a resource. The project distinguishes itself through a hig

This project is a unified, cloud-native policy engine designed to decouple authorization and security logic from application codebases. It functions as a centralized authorization service that evaluates structured input data against declarative rules, enabling consistent policy enforcement across microservices, infrastructure, and continuous integration pipelines. The engine utilizes a specialized logic programming language to express complex constraints, which are compiled into an optimized intermediate representation for high-performance evaluation. By supporting both sidecar-based deployme

OpenFGA is a fine-grained authorization server and policy decision point that implements relationship-based access control. It serves as a centralized authorization service for evaluating access requests and managing relationship tuples across distributed microservices and multi-tenant environments. The engine combines relationship graphs with attribute-based access control, using the Common Expression Language to evaluate dynamic runtime attributes and conditional access rules. It handles complex hierarchies and nested permissions by traversing chains of associations and parent-child links t

Cerbos is an open-source authorization service that provides a centralized, language-agnostic engine for managing access control. It functions as a policy-as-code platform, allowing teams to define, test, and distribute authorization rules using declarative YAML or JSON configurations. By decoupling access logic from application code, it enables consistent permission enforcement across diverse service stacks. The project distinguishes itself through its ability to translate high-level authorization policies into native database query filters. This capability allows applications to enforce sec

Casbin is an authorization library designed to manage application access control and permissions through a configurable model-based engine. It serves as a centralized system for verifying whether a user has permission to perform specific actions on a resource. The engine supports multiple access control models, including Role-Based Access Control, Attribute-Based Access Control, and Access Control Lists. It allows for the definition of role hierarchies and the evaluation of user, resource, and environment attributes to make access decisions. The library decouples authorization logic from dat

Ory Keto is an open-source authorization server that implements Google Zanzibar’s relationship-based access control model. It stores every access relationship as a tuple in a SQL database and exposes a declarative TypeScript-like namespace language for defining object types, relations, and permissions. The service provides bidirectional permission resolution, configurable consistency levels for checks, and dual gRPC and REST APIs for broad integration. Keto extends the Zanzibar model with edge enforcement of access policies, structured compliance auditing of permission decisions, and infrastr

Conftest is a suite of tools designed for validating structured configurations, testing policy logic, and generating policy documentation. It serves as a configuration file validator that checks YAML, JSON, and Helm charts for security violations and compliance issues using declarative rules. The project functions as an Open Policy Agent testing tool, allowing structured configuration files to be validated against custom policies written in Rego. It includes a policy-as-code testing framework to ensure policy logic is correct and a utility to extract metadata from Rego code to create static m

Envoy is a high-performance, cloud-native service proxy designed for service-to-service communication in distributed architectures. It functions as a service mesh data plane, providing a centralized mechanism for managing, securing, and observing network traffic between microservices. The project is distinguished by its ability to perform dynamic traffic management and configuration updates in real-time without requiring service restarts or downtime. It utilizes a non-blocking, event-driven architecture to handle high-concurrency connections and supports hot-restart process management, which

The Common Expression Language specification is a formal standard for a non-Turing-complete expression language designed for safe, portable, and fast logic evaluation. It serves as a cross-language logic standard and a declarative policy language, providing a consistent semantic framework for executing boolean expressions and data transformations across different programming environments. This specification acts as an embedded expression engine that allows applications to integrate portable logic for evaluating user-defined configurations. It is specifically designed to enable safe user-defin

Tyk is an open-source API gateway written in Go that routes, secures, and monitors network traffic across REST, GraphQL, TCP, and gRPC protocols. It functions as a multi-protocol proxy designed to deliver requests to backend services while managing the end-to-end API lifecycle. The system distinguishes itself through a plugin-based architecture that allows for the injection of custom logic into the request and response middleware chain. It also features native Kubernetes integration, operating as an ingress controller that uses operators and custom resource definitions to deploy security poli

Pundit is a Ruby authorization framework that implements policy-based access control. It maps domain models to dedicated logic classes that determine whether a user is permitted to perform specific actions on data objects. The framework utilizes plain Ruby objects to decouple authorization logic from the model. It includes mechanisms for data query scoping to filter record collections based on user permissions, as well as attribute-level permission control to restrict which specific model fields a user can modify. The system provides tools for authorization coverage verification to ensure se

Kyverno is a Kubernetes policy engine and cloud native governance tool. It functions as a policy-as-code framework that validates, mutates, and generates resources to enforce security and governance standards within a cluster. The project distinguishes itself through a declarative policy model that utilizes native Kubernetes custom resource definitions, allowing policies to be managed as standard cluster objects without custom code. It provides specific security capabilities for container image verification and signature validation to ensure only trusted images are deployed. Its broader capa