Nestjs Eventpattern, For each EventPattern decorator in some Kafka microservice controller, a new topic is c Bug Report It is not possible to have multiple handlers @EventPattern() for the same event Current behavior Creating multiple handlers for the same event does not call all of them Input Code @Event Use Case: Order Processing with Outbox Pattern in NestJS Imagine an e-commerce application where an Order Service needs to reliably publish events to Kafka when a new order is created. I am setting up basic EventPattern between two NestJS instances. js framework that provides an out-of-the-box application architecture, making it ideal for building highly scalable, maintainable, and testable applications. Current behavior It is not possible to use a RegEx for event and message patterns. Learn powerful Architectural Concepts and Patterns used in some of today's most complex NestJS applications! A while ago I wrote a blog post about using EventStore with NestJS. Aprenda a implementar uma arquitetura orientada a eventos utilizando NestJS. I am using @nest/microservices with the latest version of nextjs 6. Step 1: Set Up the NestJS Application First, create a NestJS project and install necessary dependencies: To create an event handler, we use the @EventPattern() decorator, which is imported from the @nestjs/microservices package. This system allows for precise targeting or broad matching of events through patterns. This works fine locally but whe The @nestjs/event-emitter package uses a hierarchical event naming system to organize events in a structured way. However, if an interceptor is used on the 2nd handl Is there an existing issue for this? I have searched the existing issues Current behavior When there are multiple handlers, listening to the same event (tested with Kafka), the expected behavior is. In this module, we’ll explore how to use @nestjs/event-emitter to emit and handle events, process them asynchronously, and integrate this Event-driven architecture is crucial for building truly scalable microservices, and NestJS seems like a perfect fit. However the Event is not being emitted/received by the other Microservice. This setup ensures that actions are triggered in response to certain events, facilitating a reactive microservices Event-driven architecture is a powerful design pattern that promotes loose coupling, scalability, and better organization of logic. So we emit an event and return a fast response. Master TypeScript E2E testing with Claude Code. I have inter-process communication working correctly using @EventPattern and ClientProxy. Enterprise solution for all your Social Q&A needs. I've defined a publisher that publishes events via ClientProxy. Events serve as a great way to decouple various aspects of your application, since a single event can have multiple In the previous blog, we learned the basics of communication between two services using NestJS and Tagged with nestjs, microservices, eventdriven, docker. Have you ever misused NestJS EventEmitter? Be honest. Learn to build scalable event-driven microservices using NestJS, NATS, and MongoDB. Event sourcing Event sourcing is a very simple notion: Every change Using the Saga Pattern in NestJS. NestJS, thanks to its modular design and pattern-friendly structure, is a powerful framework for building robust systems using Hexagonal Architecture and Event-Driven Architecture. Learn shared libs, CI/CD with affected builds, Docker, Kubernetes, Ingress, and API Gateway setup. Nest is a framework for building efficient, scalable Node. NestJS's EventEmitter module makes it easy to implement EDA by providing a simple yet effective way to define, emit, and handle events. Bug Report . js web applications, provides first-class support for implementing an event-driven architecture, making it a perfect fit for event sourcing. It Master TypeScript E2E testing with Claude Code. 18. A Beginner’s Guide When building bigger applications, especially ones made of multiple services, you often run into situations where a single process touches … In this post, we discuss the event-emitter technique and how to use that technique within NestJS Application. NestJS, a framework for building scalable Node. NestJS is a progressive Node. js server-side applications using TypeScript and combining OOP, FP, and FRP principles. Nest. This is meant as an updated version. A common pattern: A user deletes a record. It uses progressive JavaScript, is built with TypeScript and combines elements of OOP (Object Oriented Programming), FP (Functional Programming), and FRP (Functional Reactive Programming). That is implemented with a combination of @MessagePattern and client. 0 Late to the party here, but in case you're still looking for a solution for event-persistence: @ocoda/event-sourcing is a NestJS module that offers the basic functionality that @nestjs/cqrs provides, but also adds the necessary tools for storing and retrieving events (and snapshots). NestJS module for implementing Event Sourcing. js transforma microsserviços em potências escaláveis e eficientes. getData() to get the data about the request. Descubra como a arquitetura orientada a eventos no Nest. This object may consist of two members: The options object is specific to the chosen transporter. I ended up de-listing that post but I'm sure you'll be able to find it if you look. I need to create a consumer with the topic my-topic that is called only when the variable my-header-variable in the header has a specific value. Nov 17, 2025 · This document describes the pattern-based message routing system in NestJS microservices. I've attached the smallest reproduction so you can run it for yourself. js framework expert specializing in module architecture, dependency injection, middleware, guards, interceptors, testing w 19892 stars | by davila7 The microservice architecture structures an application as a set of loosely coupled, deployable/executable components organized around business capabilities Integrate Swetrix with your NestJS application using the @swetrix/node server-side SDK to track page views, monitor errors, and capture custom events — all while staying privacy-friendly and GDPR-compliant. I have tried to find some concrete examples on the docs, In NestJS, EventPattern is a decorator provided by the @nestjs/microservices module that allows a service to listen for events with a specific pattern. Looking forward to learning more about how you implement this with message About this library @ocoda/event-sourcing is a powerful library designed to simplify the implementation of advanced architectural patterns in your NestJS application. It provides essential building blocks to help you implement Domain-Driven Design (DDD), CQRS and leverage Event Sourcing to tackle the complexities of modern systems. The EventBus module allows you to subscribe to specific events and trigger them as needed. The TCPtransporter exposes the properties described below. By following the steps outlined in this article, you can start leveraging the benefits of EDA in your NestJS applications, leading to NestJS is a framework for building efficient, scalable Node. For other transporters (e Feb 3, 2023 · NestJS provides several tools to implement the event-driven design pattern, including the @EventPattern () decorator, which can be used to define events, and the EventBus module, which acts as a centralized hub for managing events and listeners. emit() as Feature Request The current strategy of topic creation for kafka microservices does not follow best practice. Event-Driven Architecture (EDA) is an increasingly popular approach in modern systems that require Tagged with nestjs, microservices, typescript, backend. I'm running @nestjs 7. I am using a Kafka server to emit events and NestJS to consume them. Bug Report Current behavior Given two controller route handlers that subscribe to the same @EventPattern, both handlers are executed as expected. send('my_pattern', A progressive Node. Jun 21, 2020 · With nestjs microservices, you can send messages and receive the result using request/response-based approach. Build a production-ready monorepo with NestJS and Nx. emit. Master event schemas, distributed transactions, and production deployment strategies. Here is the So long as @EventPattern() is from @nestjs/microservices and not some other package, you should be able to use context. In NestJS, you can leverage the built-in event emitter system to handle events asynchronously within your application. This is possible when using KafkaJS library but is not possible in NestJS Input Code Having a controller emitting a message 'pre-notify-post' NestJS is a progressive Node. js server-side applications. x. In NestJS, microservices are a way to build distributed applications by splitting a large application into smaller, independent services… Nestjs Application In this section, we will focus on how we can implement CQRS and Event Sourcing on NestJS. We don't want them to wait for S3 file cleanup. - NickTsitlakidis/event-nest I'm trying to setup a NestJS Hybrid Application that listens to a Redis service for events and triggers a handler in my code. Use Docker, Jest, and GWT patterns to test NestJS apps with real Kafka, Postgres, and Redis infrastructure. It covers the `@MessagePattern` and `@EventPattern` decorators, pattern registration and matching, wildcard su Jun 12, 2025 · Understanding @MessagePattern vs @EventPattern in NestJS Microservices (with Kafka Examples) When working with NestJS microservices, especially with a message broker like Kafka, it’s crucial to To instantiate a microservice, use the createMicroservice() method of the NestFactoryclass: The second argument of the createMicroservice() method is an optionsobject. Applying Event-Sourcing, CQRS, and Domain-Driven Design with NestJS - eliranna/event-sourcing-with-NestJS-example NestJS allows for the easy setup of event listeners within services or modules. This document explains the modular architecture of the NestJS backend, detailing how the five core modules (Auth, Events, Tickets, Users, Food) are organized, structured, and interact with each other. In my last blog, I roasted developers who treat the repository pattern like a junk drawer—cramming it Tagged with backend, tutorial, architecture, eventdriven. js framework for building efficient, reliable, and scalable server-side applications — Using modern JavaScript, built with Typescript, combining elements of OOP, FP Event Emitter package (@nestjs/event-emitter) provides a simple observer implementation, allowing you to subscribe and listen for various events that occur in your application. I've regretted that post for a while because the pattern I advocated for was overly complex and introduced abstractions for no good reason. 6. I'm following the instructions on how to wire up Redis to emit and receive events. One of its lesser-discussed but highly useful features is the E A collection of NestJs libraries to help you build applications based on event sourcing. Contribute to ArkerLabs/event-sourcing-nestjs development by creating an account on GitHub. switchToRpc(). js framework for building efficient, scalable, and enterprise-grade server-side applications with TypeScript/JavaScript 🚀 - nestjs/nest Jun 8, 2024 · Conclusion Event-driven architecture is a powerful approach for building scalable, maintainable, and responsive applications. pat4, gbnu, oxsqb, cwpoj, dvmm1, nim6o7, fulvba, 5rskj, edlhu, a7rjl,