UptimeRobot

Free for first 100,000 requests (Rails only)

Uptime Monitoring free for up to 100,000 events for unlimited projects and unlimited status pages.

Uptime monitoring, incident management, on-call scheduling/alerting, and status pages in a single product. The free plan includes ten monitors with 3-minute check frequency and status pages.

Automated API testing and monitoring. Free plans for teams and individuals.

Cron job and heartbeat monitoring and status pages for scheduled tasks, backups and background jobs, MCP server available. Free tier: 10 checks, 200 ping log entries, email/chat/webhook alerts, no credit card. Open Source support program for qualifying OS projects.

Rails APM with request-based pricing: live traces, slow SQL, N+1 detection, and error tracking. Free forever for 50k requests/month, 7-day retention, 1 app, 1 uptime check, and email alerts. No credit card required.

Heartbeat monitoring for cron jobs, plus HTTP uptime and TLS expiry checks, and a Laravel package that creates checks from your scheduler. Free tier with 10 checks, HTTP interval from 5 min, 30 days of history, 50k pings/mo.

Uptime monitoring: 20 free, Linux and Windows Server monitoring: 5 free, Status page: 1 free - Mobile app, multiple notification channel, and much more!