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This middleware automatically parses WebSocket requests with a JSON body and converts the body into an object.

It can also be used in combination with validator as a prior step to normalize the event body input as an object so that the content can be validated.

If the body has been parsed as JSON, you can access the original body through the request.event.rawBody.


To install this middleware you can use NPM:

npm install --save @middy/ws-json-body-parser


  • reviver (function) (default undefined): A reviver parameter may be passed which will be used JSON.parseing the body.

Sample usage

import middy from '@middy/core'
import wsJsonBodyParserMiddleware from '@middy/ws-json-body-parser'
import wsResponseMiddleware from '@middy/ws-response'

const lambdaHandler = (event) => {
return event.body.message

export const handler = middy()