Server-Timing Middleware

The Server-Timing Middleware provides performance metrics in the response headers.

INFO

Note: On Cloudflare Workers, the timer metrics may not be accurate, since timers only show the time of last I/O.

Import

import { Hono } from 'hono'
import { timing, setMetric, startTime, endTime } from 'hono/timing'
import type { TimingVariables } from 'hono/timing'

Usage

// Specify the variable types to infer the `c.get('metric')`:
type Variables = TimingVariables

const app = new Hono<{ Variables: Variables }>()

// add the middleware to your router
app.use(timing());

app.get('/', async (c) => {

  // add custom metrics
  setMetric(c, 'region', 'europe-west3')

  // add custom metrics with timing, must be in milliseconds
  setMetric(c, 'custom', 23.8, 'My custom Metric')

  // start a new timer
  startTime(c, 'db');
  const data = await db.findMany(...);

  // end the timer
  endTime(c, 'db');

  return c.json({ response: data });
});

Conditionally enabled

const app = new Hono()

app.use(
  '*',
  timing({
    // c: Context of the request
    enabled: (c) => c.req.method === 'POST',
  })
)

Result

Options

• total: boolean
  • Show the total response time. Default is true.
• enabled: boolean | (c: Context) => boolean
  • Whether timings should be added to the headers or not. Default is true.
• totalDescription: boolean
  • Description for the total response time. Default is Total Response Time.
• autoEnd: boolean
  • If startTime() should end automatically at the end of the request.
  • If disabled, not manually ended timers will not be shown.
• crossOrigin: boolean | string | (c: Context) => boolean | string
  • The origin this timings header should be readable.
    • If false, only from current origin.
    • If true, from all origin.
    • If string, from this domain(s). Multiple domains must be separated with a comma.
  • See docs.
  • Default is false