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Features

Dubly packs powerful URL shortening capabilities into a simple, self-hosted package. Here’s everything you can do with it.

Custom slugs

Choose your own memorable short URLs or let Dubly generate random 6-character slugs

Multi-domain support

Configure multiple custom domains and choose which one to use for each link

Bulk operations

List, search, and filter links with pagination support via the API

Soft deletes

Deleted links return HTTP 410 Gone instead of 404, preserving link history
Every link can include:
  • Title - A human-readable name for the link
  • Tags - Organize links with comma-separated tags
  • Notes - Internal notes for documentation
  • Destination - The target URL (can be updated at any time)

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Automatic slug generation

When you don’t provide a custom slug, Dubly generates a cryptographically random 6-character Base62 string using crypto/rand. The system automatically retries up to 10 times if a collision occurs.

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Analytics and tracking

Click tracking

Every click is recorded with timestamp, IP, user agent, and referrer information

Geographic data

Optional GeoIP integration tracks country, city, region, and coordinates

Device insights

Automatically parse browser, OS, and device type from user agents

Referrer tracking

See where your traffic comes from with full referrer domain extraction

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Analytics metrics

Dubly tracks comprehensive metrics for each link:
  • Total clicks - All-time click count
  • Today’s clicks - Clicks from the current day
  • 7-day trends - Current week vs. previous week comparison
  • Top referrers - Most common traffic sources
  • Geographic breakdown - Clicks by country
  • Browser distribution - Browser and version information
  • Device types - Desktop, mobile, tablet, etc.

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Performance optimization

Analytics are buffered in memory and flushed to SQLite in batches. The default configuration:
  • Buffer size: 50,000 events
  • Flush interval: 30 seconds
  • Non-blocking: Drops events when buffer is full instead of blocking redirects
This ensures analytics never slow down your redirects.

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Bot and traffic filtering

User-Agent detection

Filter out known bot signatures including preview fetchers and crawlers

IP-based filtering

Block datacenter IPs, Tor exit nodes, and threat intelligence feeds

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User-Agent filtering

Dubly automatically filters requests from:
  • Link preview fetchers: iMessage, Discord, Slack, WhatsApp, Facebook, Twitter, LinkedIn, Telegram
  • Search engine crawlers: Google, Bing, and other search bots
  • HTTP clients: curl, wget, python-requests, ruby, java, okhttp
  • Headless browsers: PhantomJS, Puppeteer, Selenium
  • Security scanners: Various penetration testing and scanning tools
Filtered bots still get redirected to the destination URL - they just aren’t recorded in analytics.

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IP-based filtering

The datacenter checker fetches and refreshes IP blocklists every 24 hours from:
  • Datacenter ranges: AWS, GCP, Azure, DigitalOcean, Vultr, Oracle Cloud, Akamai, Scaleway
  • Tor exit nodes: Updated list from torproject.org
  • Threat intelligence: IPsum and GreenSnow blocklists
All IP list fetches happen in parallel for fast startup and refresh.

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QR code generation

Dynamic generation

Generate QR codes on-demand for any link via the admin UI

Customization

Choose between square or circle shapes and set custom foreground colors

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QR code options

Customize generated QR codes with URL parameters:
  • Shape: square or circle
  • Foreground color: Any hex color (e.g., #FF5733)
  • Download: Add dl=1 to trigger file download
  • Format: PNG with transparent background

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Performance features

LRU cache

Frequently accessed links are cached in memory with configurable size (default: 10,000)

SQLite WAL mode

Write-Ahead Logging enables concurrent reads during writes

Indexed queries

Database indexes on domain, slug, link_id, and clicked_at for fast lookups

Batch inserts

Analytics use transaction-based batch inserts for efficient writes

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Cache behavior

  • Cache invalidation: Automatic on link update or delete
  • Key format: domain/slug for unique cache entries
  • Eviction policy: LRU (Least Recently Used)
  • Miss handling: Database query with automatic cache population

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RESTful API

Simple authentication

Single API key via X-API-Key header for all endpoints

JSON responses

Clean, consistent JSON for all API responses

CRUD operations

Full create, read, update, delete support for links

Search and pagination

Query links with search terms, limit, and offset parameters

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API capabilities

  • Create links: POST with custom or auto-generated slugs
  • List links: GET with pagination, search, and filtering
  • Get single link: Fetch by ID with full metadata
  • Update links: PATCH to modify destination, title, tags, or notes
  • Delete links: Soft delete that returns 410 Gone on redirect
All API routes require the X-API-Key header for authentication.

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Admin dashboard

The built-in web interface provides:
  • Link management: Create, edit, and delete links without API calls
  • Analytics views: Per-link and global analytics dashboards
  • QR code generation: Download QR codes with customization options
  • Search and filtering: Find links quickly by slug, destination, title, or tags
  • Session-based auth: Secure login with password protection
Access the dashboard at /admin/ on your Dubly instance.

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Deployment features

One-line install

Automated script handles Go, Caddy, systemd, and firewall configuration

Automatic HTTPS

Caddy provides automatic SSL certificate management

Graceful shutdown

Waits for in-flight requests and flushes analytics before stopping

Update script

Built-in update mechanism with --update flag

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Production ready

Dubly includes everything needed for production deployment:
  • Systemd service: Auto-restart on failure
  • Firewall rules: UFW configuration for secure access
  • Domain management: Add new domains with the add-domain.sh script
  • Optional S3 backups: Configure automated database backups to S3
  • GeoIP support: Optional MaxMind GeoLite2 integration

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Configuration flexibility

All settings are managed via environment variables:
  • Required: Password, allowed domains
  • Optional: Port, database path, GeoIP path, buffer sizes, cache size, app name
  • Defaults: Sensible production defaults for all optional settings
See the Configuration guide for complete details.

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