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JavaScript browser and server SDK

Use typed JavaScript helpers to install tracking in your website or call Jelto APIs from your application server. Both examples below belong in your own project.

Not published yet. The SDK package is prepared but has no public installation address yet. Replace the uppercase installation placeholders below after publication. They are not working registry coordinates.

Setup steps

  1. Install the published package in your project.
  2. Choose the browser entry for website tracking or the server entry for scoped APIs.
  3. Initialize with the matching product and endpoint values.
  4. Verify a pageview or inspect the API result, following the relevant example below.

Install when published

Replace REPLACE_WITH_PUBLISHED_JELTO_ANALYTICS_PACKAGE with the future package address. The prepared package exposes @jelto/analytics/browser and @jelto/analytics/server. The server entry requires Node.js 22 or later.

npm install REPLACE_WITH_PUBLISHED_JELTO_ANALYTICS_PACKAGE

Browser setup

Use this installation instead of a separate HTML tracker tag. Call it once after the application mounts in the browser, using the script URL from Settings → Installation:

import { initialize } from '@jelto/analytics/browser'

const analytics = await initialize({
  product: 'YOUR_PRODUCT_ID',
  scriptUrl: 'YOUR_SCRIPT_URL',
  goals: true,
})
// In a later confirmed-success handler:
analytics.track('signup', { plan: 'pro' })

Register signup and plan first. goals: true loads explicit form-submit and visibility tracking. Automatic pageviews are enabled by default; do not send a manual pageview for the same navigation.

Identical repeated initialization shares the initial load, while conflicting options or an existing HTML installation fail. A failed script load requires a page reload before trying again. scriptUrl must end in jelto.js or jelto.cookie.js. Cookie mode and first-touch memory are separate explicit choices.

Server setup

Keep the key in your server environment. The endpoint is your Jelto API origin, not the script URL or /v1/e path.

import { createClient } from '@jelto/analytics/server'

const apiKey = process.env.JELTO_API_KEY
if (!apiKey) throw new Error('Set JELTO_API_KEY on the server')
const jelto = createClient({
  endpoint: 'YOUR_JELTO_API_ORIGIN',
  product: 'YOUR_PRODUCT_ID',
  apiKey,
})
const result = await jelto.stats({
  from: '2026-09-01', to: '2026-09-07', metric: 'visitors',
})
if (result.ok) console.log(result.data.total)

Use analytics:read for reporting, funnels:read or funnels:write for the respective funnel operations, and payments:write for verified payments. See API keys and Website API.

Verify and handle failure

Use website verification for browser collection. On the server, inspect result.ok and the returned error details; preserve unavailable metric states rather than replacing them with zero. Requests do not automatically retry mutations. Reuse the same transaction ID when retrying a payment.

This SDK does not provide an identify method or arbitrary server-side visitor events. Use the separate crawler SDK for server crawler reporting.