Kibitzr

Kibitzr is a Python-based web monitoring tool that runs entirely from a YAML configuration file. You define what to fetch, how to transform the result, and where to send notifications. A check might fetch a URL, extract a specific element with a CSS selector, compare it to the last run, and post to Slack if anything changed — all described in a dozen lines of YAML.

The transform pipeline is where Kibitzr’s flexibility shows. Raw HTML or JSON from a fetch can pass through a chain of transformations: CSS selectors, XPath expressions, Python code snippets, Jinja2 templates, and shell scripts. This means you can handle anything from a simple “did this text change” check to extracting a specific data point from a complex API response and formatting it before sending.

Notifications are pluggable. The built-in targets cover Slack, email, Telegram, IFTTT, and arbitrary HTTP endpoints. If you need to send somewhere custom, an HTTP notifier with a JSON body template covers most scenarios. Multiple notifiers can be chained on a single check.

For pages that require JavaScript rendering, Kibitzr supports Selenium with Firefox, but this substantially increases complexity and resource usage. For most monitoring use cases — static pages, JSON APIs, simple HTML extraction — the default HTTP fetch works without a browser.

The limitation is project activity. With 713 GitHub stars and infrequent commits, Kibitzr is functional but not actively maintained. For simple monitoring scenarios it works reliably. For teams wanting active development, a broader community, and a web UI, changedetection.io is a more actively maintained alternative in the same category.