Integration guide

Wire PostCow in under two minutes

One script tag → pageviews, custom events, and grouped JavaScript errors. Static sites, SPAs, and SSR apps all POST to the same capture endpoint. Copy, paste, ship.

~2 KB tracker POST /api/v1/capture CORS-ready Self-hostable

Quick start

Three steps to live data

Create a domain

Paste the snippet

One deferred script tag before </body> on every page.

Confirm traffic

Load your site, refresh the dashboard — pageviews appear in seconds.

Install

The snippet

Paste before </body> on every page you want to monitor.

<meta name="generator" content="PostCow">
<script id="PostCow-tracker" src="https://track.libreapps.xyz/PostCow.js" data-key="YOUR_DOMAIN_API_KEY" data-PostCow-key="YOUR_DOMAIN_API_KEY" data-host="https://track.libreapps.xyz" data-PostCow="tracker" data-analytics-provider="PostCow" data-error-tracker="PostCow" defer></script>

Replace YOUR_DOMAIN_API_KEY with the key from Dashboard → Domain → Setup. When your site and PostCow run on different origins, keep data-host="https://track.libreapps.xyz".

Verify

Sanity checks

Script loads: https://track.libreapps.xyz/PostCow.js returns JS with X-Powered-By: PostCow
Add data-debug — console logs each capture attempt
Network tab shows POST /api/v1/capture with status 200
Dashboard overview updates within a few seconds of a page load

Reference

Script tag attributes

Attribute	Required	Description
data-key	Yes	Domain API key from the dashboard (lt_…)
data-PostCow-key	Alias	Same as data-key — helps tech detectors find PostCow
data-host	Cross-origin	PostCow origin, e.g. https://track.libreapps.xyz — required when script loads from a different host
data-debug	Optional	Log capture attempts to the browser console
data-privacy	Optional	Set to "minimal" when account privacy mode is on
data-visitor-profiles	Optional	Send language, screen, timezone, UTM tags when enabled on the domain
defer	Recommended	Non-blocking load; pageview fires on window load

Canonical URL: /PostCow.js. Legacy alias: /track.js and /PostCow.js (301 redirect).

API

window.PostCow

`PostCow.track(name, props?)`

Fire a custom event with optional flat JSON props

`PostCow.pageview()`

Manual pageview — call on SPA route changes

`PostCow.captureError(msg, stack?)`

Report a caught error to the dashboard

`PostCow.version`

Tracker version string baked into the script

Events

Custom events

Track button clicks, signups, checkout steps — anything you'd funnel. Properties are a flat JSON object (strings, numbers, booleans).

PostCow.track('button_click', { id: 'hero-cta' });

SPAs

Client-side routing

The snippet fires one pageview on load. Routers must call pageview() on navigation.

SvelteKit

import { afterNavigate } from '$app/navigation';

afterNavigate(() => {
  window.PostCow?.pageview();
});

React / Next.js

useEffect(() => {
  window.PostCow?.pageview();
}, [pathname]);

Errors

Error tracking

Automatic on load — no extra code for uncaught exceptions or unhandled promise rejections. Issues group by message + stack fingerprint in the dashboard. Click any issue for full stack traces, URLs, and occurrence history.

Manual capture for caught errors:

try {
  riskyOperation();
} catch (err) {
  PostCow.captureError(err.message, err.stack);
}

HTTP

Capture API

POST https://track.libreapps.xyz/api/v1/capture · Content-Type: application/json

{
  "apiKey": "lt_...",
  "type": "pageview",
  "url": "https://yoursite.com/pricing",
  "pathname": "/pricing",
  "referrer": "https://google.com"
}

pageview

type, apiKey, url, pathname — referrer optional

error

type, apiKey, message — stack, url, pathname recommended

event

type, apiKey, name — properties optional

Transport

sendBeacon first, fetch with keepalive + CORS as fallback

Frameworks

Works where you ship

Plain HTML

Paste the snippet before </body>. No build step.

SvelteKit

Add to app.html or root layout, then hook client navigations.

import { afterNavigate } from '$app/navigation';

afterNavigate(() => {
  window.PostCow?.pageview();
});

React / Next.js

Load with next/script afterInteractive, pageview on pathname change.

useEffect(() => {
  window.PostCow?.pageview();
}, [pathname]);

Vue / Nuxt

router.afterEach(() => PostCow.pageview())

Astro

Base layout before </body>. Full reloads track automatically.

WordPress

Footer hook or theme — one script line in header/footer.

Privacy

What gets collected

By default

Page URL and pathname
Referrer (may be empty)
User agent
Error message + stack
Custom event props you send

Not included

Cross-site tracking cookies
Automatic PII extraction
Fingerprinting IDs (unless you enable visitor profiles)

Enable strict privacy mode in account settings to strip URLs, referrers, and stacks. Don't put emails or passwords in event properties.

Debug

Troubleshooting

No pageviews in dashboard

Confirm data-key matches the domain in your dashboard
Network tab → POST to /api/v1/capture should return 200
Add data-debug and watch the console for send logs
Cross-origin? Set data-host to your PostCow origin
Ad blockers may block analytics — self-host on a first-party subdomain

SPA only shows landing page

Call PostCow.pageview() after every client-side navigation
SvelteKit: afterNavigate. Vue: router.afterEach. React: effect on pathname

CORS errors on capture

data-host must match the PostCow server origin exactly
No trailing slash on data-host
Registered domain hostname must match the site sending events

Errors not grouping

Uncaught errors auto-capture — caught errors need captureError()
Privacy mode strips stacks — grouping still works on message fingerprint
Click an issue in Errors for full stack + occurrence history

Self-host

Run your own instance

git clone <your-postcow-repo>
cd PostCow
bun install
cp .env.example .env   # add Supabase + PUBLIC_SITE_URL
bun run dev

Run Supabase migrations in order (001_postcow.sql first, then 002–012) — or supabase db push
Production: bun run build → deploy to Vercel or Node adapter
Set PUBLIC_SITE_URL to your public origin (e.g. https://track.libreapps.xyz)
Tip: serve tracker from t.yoursite.com to dodge ad blockers

Get started

Ready to ship?

Create a domain, paste the snippet, add data-debug, watch the network tab. Truth lives there.

Open dashboard Feature overview