a body parser for koa

Usage no npm install needed!

<script type="module">
  import koaBodyparser from 'https://cdn.skypack.dev/koa-bodyparser';



NPM version build status Coveralls David deps node version Gittip

A body parser for koa, based on co-body. support json, form and text type body.

Notice: this module don't support parsing multipart format data, please use co-busboy to parse multipart format data.




var Koa = require('koa');
var bodyParser = require('koa-bodyparser');

var app = new Koa();

app.use(async ctx => {
  // the parsed body will store in ctx.request.body
  // if nothing was parsed, body will be an empty object {}
  ctx.body = ctx.request.body;


  • enableTypes: parser will only parse when request type hits enableTypes, support json/form/text/xml, default is ['json', 'form'].

  • encoding: requested encoding. Default is utf-8 by co-body.

  • formLimit: limit of the urlencoded body. If the body ends up being larger than this limit, a 413 error code is returned. Default is 56kb.

  • jsonLimit: limit of the json body. Default is 1mb.

  • textLimit: limit of the text body. Default is 1mb.

  • xmlLimit: limit of the xml body. Default is 1mb.

  • strict: when set to true, JSON parser will only accept arrays and objects. Default is true. See strict mode in co-body. In strict mode, ctx.request.body will always be an object(or array), this avoid lots of type judging. But text body will always return string type.

  • detectJSON: custom json request detect function. Default is null.

      detectJSON: function (ctx) {
        return /\.json$/i.test(ctx.path);
  • extendTypes: support extend types:

      extendTypes: {
        json: ['application/x-javascript'] // will parse application/x-javascript type body as a JSON string
  • onerror: support custom error handle, if koa-bodyparser throw an error, you can customize the response like:

      onerror: function (err, ctx) {
        ctx.throw('body parse error', 422);
  • disableBodyParser: you can dynamic disable body parser by set ctx.disableBodyParser = true.

app.use(async (ctx, next) => {
  if (ctx.path === '/disable') ctx.disableBodyParser = true;
  await next();

Raw Body

You can access raw request body by ctx.request.rawBody after koa-bodyparser when:

  1. koa-bodyparser parsed the request body.
  2. ctx.request.rawBody is not present before koa-bodyparser.

Koa 1 Support

To use koa-bodyparser with koa@1, please use bodyparser 2.x.

npm install koa-bodyparser@2 --save