Observed arrival · 2026-08-25

Uptime Cairn, a self-hosted monitor with a stubborn sense of detail

uptimecairn.dev Observed source

Editorial interest 82/100 Selection signal · not a rating of the site

An open-source uptime monitor that runs in one Docker container, stores data in one file, and watches websites, ports, DNS, certificates, containers, and more.

Landing page captured for the 2026-08-25 issue.

Field notes

The project uses a single-container deployment with SQLite storage and binds its default HTTP port to localhost, recommending Caddy, nginx, or Traefik before internet exposure. Its checks are deliberately explicit: DNS follows every nameserver in resolv.conf, retries truncated answers over TCP, and preserves NXDOMAIN and SERVFAIL; HTTP reports the first failed assertion among four ordered tests. The page also documents ARM64 and ARMv7 images and a hardened systemd unit.

Observed signals

Read the marks

Editorial observations of this landing page, not a rating.

⊠LoginAccess appeared gated

✦PrettyNotable craft visible

●ProPolished or operationally mature

◎NicheUnusually specific use

ƒJavaScriptBrowser-side code central

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