Zetlynchangedetection.io's figures are from its site and README as of 21 October 2026.
| Zetlyn | changedetection.io | |
|---|---|---|
| Licence | MIT | Apache-2.0 |
| Run it yourself | one Rust binary and one SQLite file, or Docker | Docker, Python |
| Hosted | 9.99 € a month, VAT included, 10 watches | $8.99 a month, up to 5,000 URLs |
| Free | 1 watch for 3 days | self-hosted |
| Most often | every minute | from about 5 minutes (hosted) |
| Pages made by scripts | read in Chrome | read in Chrome |
| Notifications | email, Telegram, Slack, Discord, signed webhook | over 85 kinds |
| Filters | a place by clicking it; conditions below, above, contains, no longer contains | CSS, XPath, JSONPath, jq, text triggers |
| JSON and feeds | JSON fields and RSS/Atom entries as places | JSON API monitoring with JSONPath or jq |
| AI assistants | MCP server with OAuth | LLM summaries of changes |
When Zetlyn fits
- You want an assistant such as Claude or ChatGPT to make and change watches for you.
- You want the value before and after, and a message only when a condition comes true.
- You want one binary and one file on your own server.
When changedetection.io fits
- You watch hundreds or thousands of pages on the hosted plan.
- You need XPath, jq or one of its many notification services.