Eclipse Vert.x Reactive applications on the JVM
import io.vertx.core.AbstractVerticle;

public class Server extends AbstractVerticle {
  public void start() {
    vertx.createHttpServer().requestHandler(req -> {
        .putHeader("content-type", "text/plain")
        .end("Hello from Vert.x!");
import io.vertx.core.AbstractVerticle

class Server : AbstractVerticle() {
  override fun start() {
    vertx.createHttpServer().requestHandler { req ->
        .putHeader("content-type", "text/plain")
        .end("Hello from Vert.x!")
vertx.createHttpServer().requestHandler({ req ->
    .putHeader("content-type", "text/plain")
    .end("Hello from Vert.x!")


Han­dle more re­quests with less re­sources com­pared to tra­di­tional stacks and frame­works based on block­ing I/O. Vert.x is a great fit for all kinds of ex­e­cu­tion en­vi­ron­ments, in­clud­ing con­strained en­vi­ron­ments like vir­tual ma­chines and con­tain­ers.

Don’t waste re­sources, in­crease de­ploy­ment den­sity and save money!

Concurrent and asynchronous

Peo­ple told you asyn­chro­nous pro­gram­ming is too hard for you? We strive to make pro­gram­ming with Vert.x an ap­proach­able ex­pe­ri­ence, with­out sac­ri­fy­ing cor­rect­ness and per­for­mance.

You pick the model that works best for the task at hand: call­backs, promises, fu­tures, re­ac­tive ex­ten­sions, and (Kotlin) corou­tines.


Vert.x is a toolkit, not a frame­work, so it is nat­u­rally very com­pos­able and em­bed­d­a­ble. We have no strong opin­ion on what your ap­pli­ca­tion struc­ture should be like.

Se­lect the mod­ules and clients you need and com­pose them as you craft your ap­pli­ca­tion. Vert.x will al­ways adapt and scale de­pend­ing on your needs.

Vert.x is fun

For­get com­plex­ity and costly ab­strac­tions. With Vert.x, what you write is ac­tu­ally what you get to ex­e­cute! Get back to sim­ple de­signs, for­get some of the es­tab­lished “best prac­tices”, and enjoy writ­ing code that is com­pre­hen­si­ble and that won’t let you down in the fu­ture.

We also have a friendly com­mu­nity, so you can learn from peo­ple who have used Vert.x in very di­verse set­tings.


Web APIs, data­bases, mes­sag­ing, event streams, cloud, reg­istries, se­cu­rity… you name it. Vert.x has you cov­ered with a com­pre­hen­sive end-​to-end re­ac­tive clients stack for mod­ern ap­pli­ca­tions.

And if you can’t find what you are look­ing for, there is a very strong chance that some­one else has done it in the wider Vert.x open-​source ecosys­tem. Vert.x is a safe in­vest­ment for your tech­nol­ogy stack.

Read about Vert.x

Vert.x in Action teaches you how to build responsive, resilient, and scalable JVM applications with Vert.x using well-established reactive design patterns.

Vert.x in Action book cover
“Fantastic introduction into Vert.x written for developers looking to develop services more efficiently in terms of time and resources.”
Andrew Buttery
“A great book to add to your personal library of books that discuss the major architectural challenges of writing messaging frameworks.”
Earl B. Bingham
“Provides not only an excellent introduction to Vert.x, but reactive programming with Java in general.”
Damian Esteban
Get the book!

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