@vdaluz/astro-opt-in-analytics

Consent-first analytics for Astro. The tracker script does not exist on the page until the visitor says yes: no requests, no fingerprinting surface, nothing to block. An opt-in prompt asks once, the answer is remembered, and refusing is exactly as easy as accepting.

Built for Umami first, with a small adapter interface for other trackers. Ships raw .astro and .ts - the consuming app's Astro/Vite compiles them (no prebuild step).

Why opt-in

Most "privacy-respecting analytics" setups still track by default and put the burden of blocking on the visitor. This package flips the default: tracking is off until a real yes. That costs you data. That is the point.

• Zero requests until consent. The script tag is injected only after a stored grant. Denied or unanswered means it never exists.
• Global Privacy Control is an answer. navigator.globalPrivacyControl === true counts as a no. The prompt never shows; asking again would be its own dark pattern.
• Anti-dark-pattern by construction. Equal-weight buttons, decline first in DOM order, Esc or dismissal means deny, no overlay, no scroll lock. These are hard-coded, not configurable.
• Changeable, both directions. openConsentPrompt() (or any element with data-open-analytics-prompt) reopens the prompt, e.g. from a footer "Analytics preferences" link.

Install

Pinned https tarball from a tag (no registry needed):

// package.json
"dependencies": {
  "@vdaluz/astro-opt-in-analytics": "https://github.com/vdaluz/astro-opt-in-analytics/archive/refs/tags/v0.1.0.tar.gz"
}

Why a tarball, not github:...? npm canonicalizes GitHub shorthand to git+ssh:// in the lockfile, and CI runners without SSH keys fail to clone it. The archive URL is anonymous https with an integrity hash. Bump the tag in the URL to upgrade.

Peer dependency: astro >= 6.

Use

// src/config/analytics.ts
import { defineAnalyticsConfig, umami } from '@vdaluz/astro-opt-in-analytics';

export const analytics = defineAnalyticsConfig({
  tracker: umami({
    src: 'https://umami.example.net/script.js',
    websiteId: '00000000-0000-0000-0000-000000000000',
    extra: { 'data-exclude-search': 'true' },
  }),
  prompt: {
    message: 'Can I count your visit? Anonymous, cookieless, self-hosted analytics. No is a fine answer.',
    accept: 'Count me',
    decline: 'No thanks',
  },
});

---
// src/layouts/Layout.astro
import ConsentGate from '@vdaluz/astro-opt-in-analytics/ConsentGate.astro';
import ConsentPrompt from '@vdaluz/astro-opt-in-analytics/ConsentPrompt.astro';
import { analytics } from '../config/analytics';
---
<!-- Gate before prompt, both once per page -->
<ConsentGate config={analytics} />
<ConsentPrompt config={analytics} />

Footer link, no JS required:

<button type="button" data-open-analytics-prompt>Analytics preferences</button>

Privacy explainer page

PrivacyExplainer.astro renders the substantive sections of a /privacy page - what's collected, how consent gates it, and which tools are behind it - sourced directly from your analytics config so the page can't drift from what's actually injected. Wrap it in your own layout and hero copy:

---
// src/pages/privacy.astro
import Layout from '../layouts/Layout.astro';
import PrivacyExplainer from '@vdaluz/astro-opt-in-analytics/PrivacyExplainer.astro';
import { analytics } from '../config/analytics';
---
<Layout title="Privacy & Analytics">
  <h1>Privacy &amp; analytics</h1>
  <PrivacyExplainer config={analytics} locale={Astro.currentLocale} />
</Layout>

The "tools behind it" list only shows trackers that carry a privacyInfo field. Both bundled adapters set a sensible default - umami() points at umami.is/privacy, cloudflareBeacon() at cloudflare.com/web-analytics - override privacyInfo per adapter call to customize the label or add a description clause about your specific deployment (e.g. "that I run myself, on my own infrastructure"). A tracker with no privacyInfo is simply omitted from the list.

Cloudflare Web Analytics

cloudflareBeacon({ token }) builds the manual (non-auto-injected) beacon script tag, gated by consent like any other adapter:

import { cloudflareBeacon } from '@vdaluz/astro-opt-in-analytics';

cloudflareBeacon({ token: '00000000000000000000000000000000' });

This requires switching off Cloudflare's edge auto-injection for the zone (dashboard: Web Analytics → Manage Site → enable "JS snippet installation") - otherwise the auto-injected beacon loads unconditionally alongside this one, bypassing consent.

How it works

1. ConsentGate reads a versioned record from localStorage (opt-in-analytics:consent). Grant: the tracker <script> is injected. Anything else: nothing loads. tracker also accepts an array of adapters; one grant injects all of them (e.g. Umami plus a manually-installed Cloudflare Web Analytics beacon), and the prompt copy should disclose every tracker it covers.
2. ConsentPrompt shows only when there is no decision and no GPC signal. The answer is stored as { v, decision, at }.
3. Bump consentVersion in your config when what you track changes; older stored decisions re-prompt.
4. A denial after a grant applies from the next navigation (the already-loaded script is not surgically removed; nothing new ever loads).

Styling

The prompt reads CSS custom properties with sensible dark fallbacks: --surface, --fg, --border, --accent, --on-accent. Same token contract as @vdaluz/astro-blog: values are R G B channel triplets (e.g. --surface: 26 26 26;), consumed as rgb(var(--name)). If your app already defines those, the prompt matches your theme with zero extra CSS.

Consumers

• vdaluz.com
• imperfectsystems.com

License

MIT