Sentinel review
Affordable API checks with JSON assertions, multi-region monitoring, and MCP access.
Reviewed by iTechGuides Editors · Editorial team · Updated Nov 2026
Sentinel is a cloud monitoring service for agencies, freelance developers, and SaaS teams that need recurring API and health-check validation. It sends requests to API and health-check endpoints, checks JSON response fields and values, and alerts teams when assertions fail. Its wider monitoring coverage includes uptime, SSL certificates, DNS records, domain expiration, keywords, ICMP ping, TCP ports, and heartbeat or cron jobs. Web, macOS, and API access support browser-based monitoring, a native menu bar app, and programmatic workflows.
According to the vendor's pricing page, Sentinel has a Free plan with up to 10 monitors, 5-minute checks, JSON/API checks, one public status page, email and Discord notifications, and read-only API and MCP access. Starter costs $14 per month billed monthly, or $144 per year billed annually, for up to 25 endpoints, 1-minute checks, heartbeat and cron monitoring, Slack and Teams alerts, and five client status pages. Pro costs $29 per month billed monthly, or $288 per year billed annually, and adds up to 100 endpoints, Lighthouse audits, full API, Terraform and provisioning access, signed webhooks, AI assistants that act, and teams with up to five members. Business costs $79 per month billed monthly, or $768 per year billed annually, with up to 300 endpoints, 15-second checks, PagerDuty, unlimited teams and members, unlimited status pages, and priority support.
The standout capability is response-aware API monitoring: custom GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS requests can be paired with JSON path assertions and multi-region checks. Incident creation, status pages, and alerts through email, SMS, Slack, Discord, Teams, and webhooks extend those checks into operational workflows. Integrations with GitHub, Terraform, command line tools, and MCP access suit teams that want monitoring connected to development or AI-assisted processes. Sentinel fits buyers seeking low-cost API validation and broad endpoint coverage; teams needing more than 300 endpoints or a faster interval than 15 seconds should consider alternatives.
Sentinel pros and cons
- Where it wins
- JSON-path assertions validate API response fields and values.
- Checks run from 15 global regions across six continents with incident creation.
- MCP, REST API, Terraform, webhooks, and major alert integrations.
- Where it doesn't
- The Free plan limits monitoring to 10 monitors and 5-minute checks.
- SMS outage alerts are limited to the United States and Canada.
- The product was founded in 2024, offering a shorter maturity history.
Sentinel fact sheet, pricing and score →
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