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AsyncAPI logo
AsyncAPI Node.js WebSocket Template

npm npm


This template generates two resources related to WebSockets:

  • Server application with WebSocket endpoint based on Express.js
  • Client HTML file with simple scripts that give you a basic API to talk to the server

Other files are for the setup of developer environment, like .editorconfig or .eslint.

Technical requirements

Specification requirements

This is a very early version of the template and not all specification features are supported:

Property name Reason Fallback Default
servers.*.url Template doesn't support variables in the server url. - -
bindings Template doesn't use websockets bindings. - -
operationId Operation ID must be set for every operation to generate proper functions as there is no fallback in place - -

Supported protocols


How to use the template

This template must be used with the AsyncAPI Generator. You can find all available options here.


# Install the AsyncAPI Generator
npm install -g @asyncapi/generator

# Run generation
ag @asyncapi/nodejs-ws-template -o output -p server=localhost

## Start the server 

# Go to the generated server
cd output

# Build generated application
npm i

# Start server
npm start

## Start the client 

# From another terminal tab open generated HTML in browser
open output/index.html

# Open developers console and follow instructions from there
# Connect with server

# Send example message
send({ greet: 'Hello from client' })

# You should see the sent message in the logs of the previously started server

Template configuration

You can configure this template by passing different parameters in the Generator CLI: -p PARAM1_NAME=PARAM1_VALUE -p PARAM2_NAME=PARAM2_VALUE

Name Description Required Default Allowed Values Example
server The server you want to use in the code. Yes - Name of the server from the list of servers under Servers object localhost

Custom hooks that you can disable

The functionality of this template is extended with different hooks that you can disable like this in the Generator CLI: -d HOOK_TYPE1=HOOK_NAME1,HOOK_NAME2 -d HOOK_TYPE2

Type Name Description
generate:after createAsyncapiFile It creates AsyncAPI file with content of the spec file passed to the generator


The most straightforward command to use this template is:

ag @asyncapi/nodejs-ws-template -o output -p server=localhost

For local development, you need different variations of this command. First of all, you need to know about three important CLI flags:

  • --debug enables the debug mode in Nunjucks engine what makes filters debugging simpler.
  • --watch-template enables a watcher of changes that you make in the template. It regenerates your template whenever it detects a change.
  • --install enforces reinstallation of the template.

There are two ways you can work on template development:

  • Use global Generator and template from your local sources:
    # assumption is that you run this command from the root of your template
    ag ./ -o output
  • Use Generator from sources and template also from local sources. This approach enables more debugging options with awesome console.log in the Generator sources or even the Parser located in node_modules of the Generator:
    # assumption is that you run this command from the root of your template
    # assumption is that generator sources are cloned on the same level as the template
    ../generator/cli.js ./ -o output


Thanks goes to these wonderful people (emoji key):

Fran Méndez

💻 🤔

Lukasz Gornicki


This project follows the all-contributors specification. Contributions of any kind welcome!