Sentinel - 2026 Pricing, Features, Reviews & Alternatives

Sentinel is a website monitoring platform designed for agencies, SaaS companies, developers, consultants, and IT teams that need reliable visibility into the health of their websites and online services.

Modern websites depend on more than uptime alone. SSL certificates expire, DNS records change, APIs fail, scheduled jobs stop running, and performance degrades long before a complete outage occurs. Sentinel helps teams identify and resolve these issues before they affect customers.

Monitor websites and services from multiple geographic regions with configurable checks and instant notifications. Sentinel supports uptime monitoring, response time tracking, SSL certificate monitoring, DNS monitoring, domain expiration monitoring, API monitoring, port monitoring, cron job monitoring, heartbeat monitoring, and performance monitoring.

Core Features

Website Monitoring

Monitor website availability and response times from multiple locations. Detect outages, slowdowns, and intermittent issues before customers report them.

API Monitoring

Verify API endpoints and validate responses using custom assertions. Ensure critical integrations and application services remain operational.

SSL Certificate Monitoring

Receive advance warnings before SSL certificates expire and prevent security warnings that can impact customer trust.

DNS Monitoring

Track DNS records and receive alerts when unexpected changes occur.

Domain Monitoring

Monitor domain expiration dates and avoid costly lapses in ownership.

Port Monitoring

Verify that essential services remain accessible and responding correctly.

Cron Job and Heartbeat Monitoring

Ensure scheduled tasks, background jobs, and automated processes continue running as expected.

Status Pages

Communicate incidents and maintenance updates through customizable status pages that keep stakeholders informed.

White-Label Reporting

Generate professional reports for clients with agency-friendly branding options.

Multi-Channel Alerting

Receive alerts through email, Slack, SMS, and webhooks to ensure incidents reach the right people quickly.

Built for Agencies

Sentinel was originally created for agencies managing multiple client websites. Agencies often learn about outages from clients instead of monitoring systems. Sentinel helps eliminate that risk by providing proactive monitoring across all client properties from a single dashboard.

Built for SaaS Teams

For SaaS companies, availability directly impacts revenue and customer satisfaction. Sentinel provides continuous visibility into website uptime, API health, certificates, and supporting infrastructure so teams can respond quickly when issues arise.

Built for Developers

Developers and consultants can monitor critical services, automate workflows with webhooks, validate APIs, and gain deeper insight into service performance without unnecessary complexity.

Whether you manage five websites or hundreds, Sentinel helps you discover issues early, reduce downtime, improve reliability, and deliver a better experience for your customers.