Build your own privacy-friendly web analytics (a personal Plausible)

What you'll learn

• Writing a cookieless tracking snippet in vanilla JavaScript under 2 KB
• Building an HTTP endpoint that validates events, filters obvious bots, and writes rows to SQLite
• Hashing visitor identifiers with a salt (a random string mixed into the hash so it cannot be reversed) so raw IP addresses are never stored
• Aggregating events into unique visitors, top pages, referrers, and countries with SQL
• Drawing a chart as inline SVG with no frontend framework

Before you start

• Node.js 20 or newer installed (node --version prints a version)
• Git installed and a GitHub account for saving your work
• A code editor such as VS Code and a terminal you are comfortable typing in
• A website you control where you can add one script tag, or just a local HTML page for testing

The build

Set up a minimal Node.js project called plausible-lite for a self-hosted analytics tool. Requirements:

- Node 20, Express 4, and better-sqlite3 as the only runtime dependencies, plus a package.json with a start script.
- Layout: server.js at the root, public/ for static assets, src/db.js for database setup.
- On first boot create data/events.db with a table events: id INTEGER PRIMARY KEY, site TEXT, path TEXT, referrer TEXT, country TEXT, device_class TEXT, visitor_hash TEXT, ts INTEGER unix milliseconds, and an index on (site, ts).
- Read PORT and SALT from .env, defaults PORT=3000 and a long random SALT; add .env and *.db to .gitignore before any commit.
- GET /health returns the JSON {"ok":true} so boot success is checkable.
- Express serves public/ as static files.
- Out of scope: no authentication, no dashboard, no ingest endpoint yet.
- Known friction: better-sqlite3 compiles a native module during install, which can take a minute or fail without build tools, so print a clear error if it does.

Build a cookieless pageview tracker and its ingest endpoint for the plausible-lite project from step 1. Requirements:

- public/plausible.js under 2 KB: vanilla JavaScript, no cookies, uses navigator.sendBeacon to POST JSON to /api/event with site, path, referrer, screen (mobile, tablet, or desktop from window width), and nothing else.
- POST /api/event computes visitor_hash as sha256(SALT + ip + user-agent + today date) truncated to 16 hex characters, rotated daily, never storing the raw IP.
- Reject requests whose user-agent matches bot, crawler, spider, or headless case-insensitively, and log how many were rejected.
- Accepted events insert into the existing events table in data/events.db.
- Add public/test.html containing <script defer src="/plausible.js" data-site="demo"> so a visit fires one pageview.
- Verification: curl a sample event and get 202, curl again with a bot user-agent and confirm rejection.
- Out of scope: no geolocation lookup, no sessions.
- Friction warning: sendBeacon cannot set custom headers, so the endpoint must accept plain JSON without any CSRF token.

Add a dashboard at /dashboard to plausible-lite that reads the events table from data/events.db. Requirements:

- Protect it with HTTP basic auth using ADMIN_USER and ADMIN_PASS from .env, returning 401 on wrong credentials.
- For ranges today, 7d, and 30d compute: unique visitors as count(distinct visitor_hash), total pageviews, top 10 paths, top 10 referrers, and top 5 countries.
- One server-rendered HTML page, dark background, system fonts, no frontend framework and no chart library.
- Draw visitors per day as an inline SVG bar chart computed from the query results.
- Support ?range=7d style switching that reloads with new numbers.
- Verification: browse public/test.html a few times, then refresh /dashboard and watch the counts move.
- Out of scope: no sessionization, bounce rate, funnels, or exports.
- Honest limit: SQLite table scans slow down around a few hundred thousand rows, which is fine for a personal site and worth stating in the README.

What you won't get

• Bot filtering limited to user-agent matching; sophisticated bots require ongoing tuning beyond a weekend build
• Query performance tuned for personal-site volumes rather than millions of monthly pageviews
• Scope covers pageviews, referrers, devices, and countries; funnels, goal tracking, and email reports sit outside it
• Privacy-by-design choices like no cookies and hashed IPs, while formal compliance sign-off for regulations such as GDPR remains your responsibility

Why people still pay — and what that teaches you

scale-infra: Plausible stores events in ClickHouse, a column database built so dashboards answer in milliseconds even at millions of pageviews. A builder learns that fast aggregation at scale is an infrastructure discipline with real operating costs, not a code feature you can copy into a weekend project.

compliance-regulatory: Part of what customers buy is relief: cookieless collection, European hosting, and a documented GDPR posture kept current as rules change. Your build can borrow the privacy techniques, and the lesson is that careful legal maintenance is itself a product that people pay for monthly.

Stretch goals

• Deploy plausible-lite to a cheap rented Linux server (a VPS) with Docker Compose, fronted by Caddy for automatic HTTPS
• Fill in real countries using MaxMind's free GeoLite2 database instead of leaving the column empty
• Email yourself a weekly top-pages digest using Nodemailer and a cron job

All steps done — did it work?

Congratulations. Tell someone what you built.

About Plausible

Plausible costs $9/month. They pay because analytics must be boring, fast, and legally safer without ops.

Sources & further reading

• Plausible Analytics source code — The paid product's own open source core, useful for comparing your tracker and queries against theirs.
• Umami — A mature self-hosted analytics app worth reading after your build to see how the same problems scale up.
• Plausible subscription plans — Shows which capabilities sit behind each paid tier, a map of what you built versus what teams pay for.
• GoatCounter — An even simpler analytics tool, helpful perspective on how small a useful version can be.

Finished alternatives (if you'd rather not build)

• GoatCounter — Even simpler than Plausible, which is either refreshing or a warning.
• Plausible Community Edition — Plausible without the hosted bill; you keep the core dashboard and inherit the Compose stack.
• Rybbit — Plausible's core plus replay and funnels, in exchange for a busier dashboard.
• Umami — The closest broad substitute: simple traffic analytics, events and goals with your data attached.

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