Skip to content

Vercel Analytics supports Next.js, Nuxt.js, and Gatsby with zero configuration through build plugins. You can use Vercel Analytics with any frontend framework or project through the Vercel Analytics API as shown below.

post /v1/vitals

Send web vitals data to the Vercel Analytics API.

Body Parameters

Body Parameter
Description

dsn

string

Unique identifier for the project, exposed during the build as an environment variable VERCEL_ANALYTICS_ID

event_name

string

Name of the vital to track, provided by the web-vitals package

href

string

The full URL for the deployed application

id

string

Unique identifier for the vital to track, provided by the web-vitals package

page

string

The file name a framework could translate into a resolved URL path

speed

string

Connection information from the visitor device, which can be provided by the web Navigator API

value

string

Value of the vital to track, provided by the web-vitals package

Response

200 OK

Response Codes

Code
Description
200
Successful response.
400
One of the body values is invalid or missing.
403
You do not have permission to access this resource.

To use the Analytics API, you'll need to retrieve the analytics ID for your Vercel project. This value is exposed during the build and can be accessed by process.env.VERCEL_ANALYTICS_ID inside Node.js.

Inside your framework or Node.js script, you can then use this value in the body of your request to the Vercel Analytics API.

Note: vc pull does not pull VERCEL_ANALYTICS_ID as the Vercel Analytics ID environment variable is inlined during the build process. It is not part of your project Environment Variables, which can be pulled locally using the CLI.

You can view an example of the following code implemented inside our Create React App and SvelteKit starters.

import { getCLS, getFCP, getFID, getLCP, getTTFB } from 'web-vitals';

const vitalsUrl = 'https://vitals.vercel-analytics.com/v1/vitals';

function getConnectionSpeed() {
  return 'connection' in navigator &&
    navigator['connection'] &&
    'effectiveType' in navigator['connection']
    ? navigator['connection']['effectiveType']
    : '';
}

function sendToAnalytics(metric, options) {
  const page = Object.entries(options.params).reduce(
    (acc, [key, value]) => acc.replace(value, `[${key}]`),
    options.path,
  );

  const body = {
    dsn: options.analyticsId, // qPgJqYH9LQX5o31Ormk8iWhCxZO
    id: metric.id, // v2-1653884975443-1839479248192
    page, // /blog/[slug]
    href: location.href, // https://my-app.vercel.app/blog/my-test
    event_name: metric.name, // TTFB
    value: metric.value.toString(), // 60.20000000298023
    speed: getConnectionSpeed(), // 4g
  };

  if (options.debug) {
    console.log('[Analytics]', metric.name, JSON.stringify(body, null, 2));
  }

  const blob = new Blob([new URLSearchParams(body).toString()], {
    // This content type is necessary for `sendBeacon`
    type: 'application/x-www-form-urlencoded',
  });
  if (navigator.sendBeacon) {
    navigator.sendBeacon(vitalsUrl, blob);
  } else
    fetch(vitalsUrl, {
      body: blob,
      method: 'POST',
      credentials: 'omit',
      keepalive: true,
    });
}

export function webVitals(options) {
  try {
    getFID((metric) => sendToAnalytics(metric, options));
    getTTFB((metric) => sendToAnalytics(metric, options));
    getLCP((metric) => sendToAnalytics(metric, options));
    getCLS((metric) => sendToAnalytics(metric, options));
    getFCP((metric) => sendToAnalytics(metric, options));
  } catch (err) {
    console.error('[Analytics]', err);
  }
}