Klaxon
Website change monitoring built for newsrooms. Get alerts when government pages, court dockets, or corporate sites change.
What should journalists know about Klaxon?
Klaxon turns the web into a tip line. Built in 2016 by Tom Meagher, Ivar Vong, and Andy Rossback at The Marshall Project — born from a specific reporting problem (tracking pending executions for 'The Next to Die'). You bookmark sections of any webpage; Klaxon checks them roughly every 10 minutes and alerts you via email, Slack, or Discord when something changes. Since December 2023, Klaxon Cloud (hosted by MuckRock via DocumentCloud) eliminates the need to run your own server — snapshots go to the Internet Archive's Wayback Machine, and checks run via GitHub Actions. The original self-hosted version (Ruby on Rails) still exists on GitHub with 675 stars, but Marshall Project has stopped supporting individual deployments. Klaxon Cloud is the path forward for solo journalists. Commercial alternatives like Visualping ($10+/mo) and Distill.io ($15+/mo) offer shinier UIs and faster check intervals, but Klaxon is free, open source, and purpose-built for journalism. That matters.
Monitoring government websites for quiet changes — budget documents, policy pages, agency rosters. Tracking court docket updates. Watching corporate press releases, regulatory filings, or FOIA disclosure logs. Any page where a silent edit is the story.
Real-time alerts (Cloud version runs on GitHub Actions schedule, not sub-minute). Pages behind logins or paywalls. Large-scale scraping (Internet Archive rate limit: 6 requests/minute even authenticated). Visual change detection — Klaxon compares HTML, not screenshots. If you need visual diffing, look at Visualping.
Security & Privacy
Data is scrambled while being sent to their servers
Data is scrambled when stored on their servers
Where servers are located — affects which governments can request your data
Privacy policy summary
Klaxon Cloud is operated by MuckRock, a nonprofit. Your watched URLs and alert history are stored on their servers and snapshots are sent to the Internet Archive. No data selling, no advertising, no tracking. Self-hosted gives you full control over all data.
How to protect yourself:
For maximum control, self-host on your own infrastructure. On Klaxon Cloud, your watched URLs are stored on MuckRock's servers and snapshots go to the Internet Archive — both are public-interest nonprofits, but avoid monitoring pages that reveal your investigation's focus if operational security is critical. The URLs you monitor are themselves a form of metadata about your reporting interests.
Open source (MIT) and operated by two nonprofits (Marshall Project, MuckRock). Self-hosted option gives full control. Klaxon Cloud relies on MuckRock/DocumentCloud infrastructure, which has a strong track record serving 2,000+ newsrooms. No sensitive content is processed — only public web page changes. Main concern: the URLs you monitor are stored on third-party nonprofit servers, which constitutes metadata about your reporting interests. For high-risk investigations, self-host or use a throwaway DocumentCloud account.
Who Owns This
Known issues
Internet Archive rate limiting caps at 6 requests/minute even with authentication — heavy monitoring setups will hit this. Open GitHub issues include timeouts when deleting pages with many snapshots (#699), snapshots occasionally not flagging as changed (#359), and a possible memory leak in the feed view (#320). Marshall Project has stopped supporting individual self-hosted deployments — the README says 'we will no longer be supporting development for individual users.' Klaxon Cloud runs on GitHub Actions, which means check frequency depends on DocumentCloud's scheduling, not a dedicated server. The tool monitors HTML changes, not rendered visual output — JavaScript-heavy SPAs may not trigger alerts correctly.
Pricing
Free. Klaxon Cloud (via MuckRock/DocumentCloud) requires a free DocumentCloud account. Self-hosted: free and open source (MIT license). No paid tiers.
This is an editorial assessment based on publicly available information as of 2026-04-02, using our published methodology. Independent security review is pending. Security posture can change at any time. This is not a guarantee of safety.
Something wrong or outdated? Report it.