StatusScout
Monitors uptime, SSL certificates, security headers, DNS records, and exposed files. Alerts via email, SMS, or ntfy. Self-hostable with free forever tier.
StatusScout is an open-source alternative to:

StatusScout is a comprehensive security and uptime monitoring tool designed for developers and agencies. It provides real-time alerts for downtime, SSL issues, missing security headers, and exposed secrets, ensuring your applications remain secure and operational.
Key Features
- Uptime Monitoring: 24/7 monitoring with instant alerts when your site stops responding.
- SSL Certificate Tracking: Alerts before certificates expire to prevent visitor warnings.
- Security Header Scanning: Automatically detects missing critical browser security headers.
- Subdomain Takeover Protection: Monitors SPF, DKIM, DMARC records and vulnerable subdomains.
- Exposed Secrets Detection: Scans for accidentally public environment files, API keys, and sensitive credentials.
- User Flow Monitoring: Scheduled tests for key user flows like signup and checkout with failure alerts.
- Multi-Channel Alerts: Supports email, SMS, and ntfy notifications.
- Self-Hosting Option: Deploy to your own server with full feature access and data ownership.
Tech / Self-Hosting
StatusScout is open-source and can be self-hosted on your own infrastructure. The self-hosted version includes all features with no restrictions, though you manage updates, backups, and infrastructure. Cloud-hosted plans are also available for managed services.
Made and hosted in the EU with renewable energy-powered infrastructure.