# Build brief — a focused alternative to PostHog

> **Verdict:** Not faithfully · **Buildability:** 28/100 · **Category:** Analytics
> **Source:** https://www.canitbevibecoded.com/posthog
> Independent editorial assessment from Can It Be Vibe Coded? Not affiliated with, endorsed by, or derived from PostHog. Verify current pricing and capabilities before acting.

## Context

**PostHog** — Product analytics with session replay, feature flags, and a data warehouse. It currently costs Variable pricing.

First-party collection and a dashboard that answers your top five questions is achievable solo, and PostHog's free tier covers a million events a month before you pay anything. What the bill buys past that is the rest of the platform: session replay, feature flags, SQL over years of events, and ingestion that stays correct while your event schema drifts underneath it.

This brief describes a focused, single-operator replacement for the part of PostHog that is genuinely reproducible. It is deliberately narrower than the product it replaces, and it says so in writing. Build the useful core; do not pretend to have rebuilt the rest.

## What you are building

Collect first-party pageviews and custom events from your own sites, keep the raw rows yourself, and answer a handful of product questions from a local dashboard.

- Ingest a known data source, calculate a focused metric set, and render a useful dashboard.
- A responsive interface with real empty, loading, success, and error states.

## Requirements

### Functional

- Node 22.
- A small always-on VPS.
- A domain you control, for first-party collection.

### Non-functional

- Accessibility: semantic markup, labelled controls, visible focus, and reduced-motion support.
- Security: server-side secrets, validated input, and no credentials in the client bundle.
- Reliability: retries with backoff on external calls, and a clear failure state when a provider is down.
- Portability: the operator can export their data and leave without losing it.

## Implementation brief

Build me a self-hosted web analytics box to replace PostHog. Requirements:

- One Node 22 + Express process with better-sqlite3, serving the collector and the
  dashboard on port 8787. No frontend framework, no build step, no Docker.
- A tracker.js I paste on my sites: pageviews on load and history change, plus
  window.track('signup', { plan: 'pro' }), POSTed to /e on my own domain so
  collection stays first-party.
- One SQLite events table: site, event, path, referrer, UTM fields, country from the
  proxy header, device class, and a JSON properties blob.
- Count visitors by a daily-rotating salted hash of IP plus user agent, salt in .env.
  No cookie, never the raw IP. That is the whole privacy design, keep it.
- Dashboard at / with a date range picker: visitors and pageviews by day, top pages,
  referrers, countries, any event split by one property, and a three-step funnel.
- Nightly rollup into a daily-summary table, raw events pruned past the retention
  window in .env, /export.csv for the raw rows.
- Basic auth on the dashboard, collector open. No accounts, no telemetry, my box
  holds the only copy.
- Out of scope: session replay, feature flags, and stitching one person across
  devices. Do not build a plugin system or a warehouse connector.
- README: the snippet to paste, where the SQLite file lives, and how to back it up.

## Delivery standard

- Inspect the repository first, then write a short implementation plan before writing code.
- Deliver the smallest complete end-to-end workflow first; every primary control must work against persisted data.
- Use real validation and storage; never substitute fake dashboards, decorative controls, hard-coded success states, or mock integrations.
- Include responsive layouts plus genuine empty, loading, success, validation, and failure states.
- Keep secrets server-side in environment variables, provide .env.example, and never commit credentials or user data.
- Add structured logs around every external call and return actionable errors without leaking sensitive details.
- Write unit tests for the core logic and one automated test of the main user journey.
- Finish with a README covering setup, architecture, data location, backups, tests, deployment, and known limitations.

## Acceptance criteria

- [ ] A clean install starts the app using only the README and .env.example.
- [ ] The primary journey works from first visit through saved result, reload, edit, export, and deletion where applicable.
- [ ] Invalid input, missing configuration, provider failure, and an empty database each have a usable state.
- [ ] The interface works at 390px and 1440px, is keyboard navigable, and shows visible focus on every control.
- [ ] Tests, type checking, linting, and a production build all pass with no ignored failures.
- [ ] No part of the interface implies a live integration, security guarantee, or scale capability that was not actually built and verified.

## Non-goals

Do not build these, and do not claim to have replaced them:

- Session replay.
- Feature flags and experiments.
- Identity stitching across devices.
- SQL over years of events.
- Reliability at the vendor's scale is an operations problem, not a prompt.
- Years of history, configuration, and habits make migration costly.

## What you still own after launch

- Run migrations, backups, restores, and dependency updates.
- Test the critical journey after every model, API, or hosting change.
- Monitor failures and fix the edge cases a first prompt will miss.

## Risk

**Operational risk.** The code is achievable; dependable data, integrations, and ongoing operations are the real cost.

Editorial confidence in this assessment: high. No independent one-shot implementation is linked yet.

## Prior art

Working open-source software you can read, fork, or borrow from before starting:

- [Umami](https://github.com/umami-software/umami) — Popular open-source privacy-focused web analytics platform

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Generated by [Can It Be Vibe Coded?](https://www.canitbevibecoded.com) · Full report: https://www.canitbevibecoded.com/posthog