Tally

A self-hosted product analytics service. Track events, identify users, and visualize trends — without paying $1000+/month for Mixpanel or Amplitude.

Built for SaaS apps that only need the 20% of analytics features that matter: event tracking, funnels, retention, and a dashboard.

Features

• Event Tracking — Track custom events with flexible JSONB properties
• User Identification — Identify users, merge anonymous sessions, track user journeys
• Funnels — Multi-step conversion funnels with time windows and property filters
• Retention — Weekly/daily cohort retention grids with segment filtering
• Real-time Dashboard — Live event feed, KPI cards, charts (Hotwire Turbo)
• Error Tracking — JS errors, promise rejections, server errors with business impact analysis
• Form Analytics — Field-level drop-off funnels, time-per-field heatmaps
• User Paths — Session flow analysis and navigation patterns
• Anomaly Detection — Z-score based spike/drop alerts with webhook notifications
• Segments — Behavioral + property-based user cohorts
• Webhooks — HMAC-signed HTTP webhooks with event filtering and auto-disable
• CSV Export — Export events, users, funnels, and retention data
• Multi-SDK Support — Ruby, JavaScript, Python, and Node.js SDKs (all zero-dependency)

Tech Stack

• Backend: Rails 8, PostgreSQL, Solid Queue
• Frontend: Hotwire (Turbo + Stimulus), Tailwind CSS, Chart.js
• Deploy: Kamal 2 + Thruster
• Auth: has_secure_password with role-based access (admin/member, owner/editor/viewer)

Architecture Highlights

• Partitioned events table — Monthly partitions for partition pruning, O(1) data retention, and faster vacuuming
• Pre-aggregated rollups — EventDailyRollup table for O(1) dashboard reads via atomic upserts
• Identity resolution — Anonymous-to-identified user merging via background jobs
• Rate limiting — Rack::Attack throttling on write and read endpoints
• Idempotency — Partial unique index on (project_id, idempotency_key, occurred_at) for safe retries
• Zero-dependency SDKs — All SDKs use only stdlib (no gem/package conflicts with host apps)

API

Write endpoints (authenticated via X-API-Key header):

• POST /api/v1/track — Track an event
• POST /api/v1/batch — Batch track events
• POST /api/v1/identify — Identify a user
• POST /api/v1/alias — Link anonymous ID to user

Read endpoints (authenticated via Bearer token):

• GET /api/v1/queries/event_counts — Event counts over time
• GET /api/v1/queries/top_events — Top events by count
• GET /api/v1/queries/user_timeline — User event timeline

Getting Started

git clone https://github.com/almokhtarbr/tally.git
cd tally
bin/setup
bin/dev

Seed demo data:

bin/rails db:seed

Visit http://localhost:3000 and follow the setup wizard.

SDK Usage

Ruby:

TallyAnalytics.configure do |c|
  c.api_key = "pk_your_key"
  c.endpoint = "https://tally.yourdomain.com"
end

TallyAnalytics.track("user@example.com", "purchase", plan: "pro", amount: 99)

JavaScript:

<script src="https://tally.yourdomain.com/sdk/tally.js"></script>
<script>
  tally('init', 'pk_your_key', { endpoint: 'https://tally.yourdomain.com' });
  tally('track', 'button_clicked', { page: '/pricing' });
</script>

Testing

bundle exec rspec

82 specs covering models, services, jobs, and API endpoints.

Deployment

Configured for Kamal 2. Update config/deploy.yml with your server details and run:

bin/kamal setup

Documentation

See the docs/ directory for detailed documentation:

• Architecture — System design and scaling considerations
• API Reference — Full API documentation
• SDK Guide — SDK integration details
• Implementation — Build order and design decisions

License

MIT