Based on https://github.com/koajs/response-time.

Install

npm install --save koa-response-time-precise

Use

const Koa = require('koa')
const responseTime = require('koa-response-time-precise')

const app = new Koa()
app.use(responseTime())
app.listen(8080)

Result

A header with response time accurate to 0.001 milliseconds is added.

HTTP/1.1 404 Not Found
X-Response-Time: 0.026ms
Content-Type: text/plain; charset=utf-8
Content-Length: 9
Date: Fri, 25 Mar 2016 01:14:40 GMT
Connection: keep-alive