Acknowledgements
Open source projects that Site Spy is built on
Site Spy's detection engine is built on top of changedetection.io, an excellent open source website change detection tool. The core functionality — page fetching, diffing, and change detection — comes from their project.
What Site Spy adds on top:
- Browser extension with a visual element picker
- Browser-first workflow (install, connect, click what you want to watch)
- Hosted multi-user infrastructure with per-user API keys
- Billing and plan management
- MCP server for AI agent integrations
- Extended notification system (email, Telegram, browser push)
changedetection.io is actively maintained and free to self-host. If you prefer running your own instance, check out their project directly.