Micronaut Security integrates seamlessly with Micronaut applications to provide JWT, OAuth2, LDAP, and custom authentication strategies.

Supports role-based and attribute-based access control for granular authorization.

Reactive and non-blocking, designed for high-performance microservices.

Simplifies secure API development with declarative annotations and configuration.

Extensible to integrate with external identity providers and custom authentication mechanisms.

Authentication mechanisms (JWT, OAuth2, LDAP, custom)

Authorization via annotations (@Secured, @RolesAllowed)

Method-level and endpoint-level security

Integration with reactive and non-reactive applications

Security filters and token validation

Authentication - verifying user identity (JWT, OAuth2, LDAP)

Authorization - determining access rights (roles, permissions)

Controller - endpoints secured with annotations

Filter - intercept requests for security processing

Token - JWT or OAuth2 access token for stateless security

src/main/java - application code

src/main/resources/application.yml - security configuration

controllers/ - endpoint definitions

services/ - user authentication and role logic

security/ - custom authentication providers or filters

Enable security feature in Micronaut project

Configure authentication provider (JWT, OAuth2, LDAP)

Annotate controllers or methods with `@Secured` or `@RolesAllowed`

Implement custom user details or token validation if needed

Test secured endpoints with appropriate credentials or tokens

Beginner: secure a single REST endpoint with JWT

Intermediate: role-based access control for multiple controllers

Advanced: OAuth2 integration with external identity provider

Expert: custom reactive security filters and token validation

Enterprise: multi-service security architecture with SSO

Micronaut Security vs Spring Security: Micronaut reactive, lightweight, compile-time; Spring Security richer ecosystem, runtime reflection

Micronaut Security vs Keycloak standalone: Keycloak full-featured IdP, Micronaut integrates IdP into services

Micronaut Security vs OAuth2 libraries: Micronaut provides framework integration and annotations

Micronaut Security vs Quarkus Security: both reactive, compile-time; Micronaut favors JVM microservices

Micronaut Security vs Express middleware: Micronaut offers declarative, typed Java/Kotlin security

2018 - Initial Micronaut Security modules introduced

2019 - JWT and OAuth2 support added

2020 - Reactive security features stabilized

2022 - LDAP and multi-provider support expanded

2025 - Latest stable version with full reactive microservices support

Authentication - verifying identity

Authorization - checking access permissions

JWT - JSON Web Token for stateless authentication

OAuth2 - protocol for delegated access

Secured annotation - declares security requirements

Install Micronaut via SDKMAN or build tools

Create a new Micronaut project with security feature: `mn create-app myapp --features security-jwt`

Configure security settings in `application.yml`

Implement controllers and secure endpoints with annotations

Run application via `./gradlew run` or `mvn mn:run`

Install Java 17+

Install Micronaut CLI or SDKMAN

Create project with security features

Configure authentication and authorization

Run app locally and verify secured endpoints

application.yml - security configuration

build.gradle / pom.xml - dependencies

src/main/java/controllers/ - secured endpoints

src/main/java/security/ - custom auth providers

src/test/java/ - security tests

mn create-app myapp --features security-jwt - create project

mn run - start application

mn test - run tests

./gradlew build - build project

mn add-feature security-oauth2 - add OAuth2 support

Security messages can be localized

JWT claims are language-agnostic

Integrates with Micronaut i18n features

Custom error messages can be externalized

Supports UTF-8 payloads

APIs accessible to authenticated clients

Supports CORS for web applications

Integrates with SSO and external identity providers

Role-based access ensures endpoint protection

Testable via automated security tests

Primarily API security (JSON)

Can integrate with front-end via OAuth2 login

Optional server-side rendering secured via annotations

Secure static resources with filters

Front-end frameworks handle auth flows via JWT/OAuth2

JWT or OAuth2 tokens manage session state

Authentication providers manage user identity

Roles and permissions define access state

Filters handle per-request security state

Reactive streams ensure concurrent state handling safely

User credentials stored in database or LDAP

Roles and permissions mapped to users

JWT tokens carry claims and expiry

Audit logs track authentication and authorization

Token validation caches for performance

Security filters intercept HTTP requests for authentication/authorization

Reactive processing ensures non-blocking behavior

Annotations applied to controllers or methods for access control

Token validation handled via Micronaut Security modules

Integration with identity providers via configuration or beans

Request enters server

Security filter intercepts request

Authentication provider verifies identity

Authorization annotations enforce access control

Controller handler executes if access granted

Annotation-based method and endpoint security

Reactive non-blocking authentication flow

Filter-based request interception

DI and AOP for modular security concerns

Token-based stateless authentication

Microservices backend with JWT/OAuth2 authentication

Serverless functions secured via Micronaut Security

API gateway enforcing centralized authentication

Enterprise applications with LDAP integration

Reactive microservices requiring low-latency security

Reactive and non-blocking

Annotation-driven declarative security

Extensible to multiple authentication strategies

Lightweight and modular

Tightly integrated with Micronaut DI and AOP

Use reactive authentication providers for high concurrency

Cache token validation for performance

Distribute authentication across microservices

Rotate JWT secrets regularly

Monitor endpoints for failed authentication attempts

Update Micronaut and security modules

Refactor deprecated annotations or configs

Test authentication and authorization flows

Deploy incrementally for production safety

Monitor security metrics and logs

Reactive filters are non-blocking for high concurrency

Token validation can be cached for frequent requests

Use asynchronous identity provider calls

Avoid blocking operations in security filters

Monitor authentication-related metrics

Use strong JWT secrets and key rotation

Validate all incoming tokens

Limit access via roles and permissions

Secure configuration files and secrets

Audit authentication and authorization logs

Monitor authentication success/failure rates

Track JWT expiration and renewal

Integrate with Prometheus/Grafana for metrics

Log authorization decisions for audit

Custom security metrics via reactive events

Follow Micronaut and Java/Kotlin conventions

Unit and integration test security flows

Modularize authentication and authorization logic

Use CI/CD for automated security testing

Ensure proper annotation and configuration usage

Secure REST API endpoints with JWT

Implement OAuth2 login with Google or Keycloak

Use method-level security with `@RolesAllowed`

Build custom authentication provider for LDAP

Add reactive token validation for high-throughput services

Check logs for authentication failures

Ensure JWT secret or OAuth2 client credentials are correct

Verify annotations are applied correctly

Debug token parsing and validation

Confirm configuration properties in `application.yml`

Use Micronaut Test with JUnit or Spock

Mock authentication providers for unit tests

Test endpoint access with valid and invalid tokens

Verify role-based access restrictions

Include integration tests for security flows

Deploy on JVM-based servers (AWS, GCP, Azure)

Docker containerization for microservices

Serverless deployments with AWS Lambda or Google Cloud Functions

Include secrets management for keys and tokens

Monitor security and authentication metrics in production

Micronaut framework

Micronaut Security modules (JWT, OAuth2, LDAP)

Gradle or Maven build tools

Micronaut Data for database access

Micronaut Test for unit and integration testing

OAuth2 providers: Google, Keycloak, Okta

LDAP authentication servers

JWT token-based stateless APIs

Database for user roles and permissions

Reactive or non-reactive Micronaut applications

Use annotation-based security for clarity

Leverage reactive JWT validation for performance

Centralize authentication providers for reuse

Test secured endpoints early

Monitor token lifecycles and roles for consistency

Configuring multiple authentication strategies

Integrating reactive security with non-blocking services

Managing JWT secrets and token expiration

Understanding annotation-based authorization

Scaling security across multiple microservices

Learn Micronaut basics

Understand security modules and features

Learn JWT and OAuth2 authentication

Implement role-based and method-level authorization

Build reactive microservices with secure endpoints

Week 1: Setup Micronaut Security and secure a single endpoint

Week 2: Add JWT authentication and role-based access

Week 3: Integrate OAuth2 login with external provider

Week 4: Implement custom authentication provider

Week 5: Deploy and monitor security in production

What is Micronaut Security and why is it reactive?

How do you implement JWT authentication in Micronaut?

Explain role-based vs attribute-based access control

How do you secure a controller method with annotations?

Compare Micronaut Security with Spring Security

mn create-app myapp --features security-jwt - create new project with JWT security

@Secured('ROLE_USER') - secure controller or method

AuthenticationProvider interface - implement custom auth

application.yml - configure JWT/OAuth2 settings

mn run - run Micronaut application

Micronaut in Action

Reactive Microservices with Micronaut

Micronaut Security Essentials

Building Cloud-Native Java Apps with Micronaut

Practical Micronaut Security Projects

Getting started with Micronaut Security

JWT authentication and authorization

OAuth2 login integration

LDAP authentication provider setup

Reactive security for microservices

https://micronaut.io/documentation/security/latest/

Micronaut GitHub repository

Community tutorials and guides

Micronaut GitHub

Micronaut Slack community

StackOverflow Micronaut tag

Official documentation and guides

Community blogs and tutorials

Micronaut GitHub repository

Micronaut Slack community

StackOverflow Micronaut tag

Official Micronaut documentation

Community blogs and tutorials

Micronaut Security is open-source (Apache 2.0)

Enterprise applications benefit from secure microservices

Integration with cloud services reduces operational risk

Supports regulatory compliance for authentication

Lightweight security reduces JVM resource costs

Expanded support for multi-tenant security

Improved reactive integrations and performance

More built-in identity provider connectors

Enhanced documentation and tutorials

Integration with new security standards and protocols

Small scripts or single endpoint projects

Teams unfamiliar with JVM languages

Rapid prototyping where security is not critical

Non-JVM tech stack projects

Applications not requiring reactive or microservices architecture

Micronaut Security provides authentication and authorization for JVM microservices.

Supports JWT, OAuth2, LDAP, and custom providers.

Reactive, lightweight, and annotation-driven.

Ideal for secure, cloud-native microservices and serverless applications.

Integrates tightly with Micronaut DI, AOP, and reactive features.

Is Micronaut Security open-source? -> Yes, Apache 2.0 license.

Does it support reactive applications? -> Yes, fully reactive.

Can I use it with Kotlin? -> Yes, fully supported.

Does it provide JWT and OAuth2? -> Yes, built-in modules.

How do I test secured endpoints? -> Use Micronaut Test with mock authentication.