Appmill is an external monitoring service from Beyond Co., Ltd. that tracks website reliability and security through automated checks. The service monitors availability, response speed, domain and SSL certificate expiration, and page integrity with simple URL registration that takes just minutes to set up.

The platform checks pages at five-minute intervals and sends alerts through email, Slack, or Chatwork when issues are detected. When errors occur, the service automatically starts scenario monitoring to check additional pages and identify the impact range.

Appmill allows completely free monitoring of up to 100 URLs with no time limit, making it practical for agencies and companies managing multiple websites. The free plan includes all basic monitoring features with Slack and Chatwork integration at no additional cost.

For URLs requiring advanced protection, the security plan adds HTML difference comparison, snapshot comparison, malware detection, social engineering protection, and broken link checks.

The service interface is primarily in Japanese, with an English version of the website available for international teams.