Summer training project · BTech CSE ’27
API Sentinel watches your endpoints around the clock, logs every request you fire, and X-rays slow responses down to the DNS lookup — then pings you on Discord before your users notice.
Free forever. Runs on your own machine with Docker.
$ sentinel watch --all
✓ payments/health 200 in 184ms · dns 12ms · tls 61ms
✓ auth/login 200 in 171ms · dns 9ms · tls 58ms
✗ webhooks/stripe timeout after 10s · retry 2/3
✗ webhooks/stripe timeout after 10s · retry 3/3
→ Discord alert sent to #incidents
What it does
Add a URL, pick an interval. Sentinel checks it on schedule and keeps 30 days of uptime, p50/p95/p99 latency and a daily heatmap.
A Postman-lite in your browser. Fire requests, inspect status, headers and timing, then replay anything from history.
Paste any URL for a full network X-ray — DNS, TCP, TLS and TTFB in a waterfall, so you see exactly where the milliseconds go.
Three failed checks in a row and your server hears about it. One message per outage, one when it recovers — no spam.
Group requests into collections. Swap {{base_url}} between dev, staging and prod with a single click.
Every check is a metric. Scraped by Prometheus, graphed in Grafana — the dashboards ship in the repo, ready to open.
How it works
01
Paste the URLs that matter — health checks, webhooks, third-party APIs. Anything that answers HTTP.
02
Checks run on your schedule. Every result is logged, timed and turned into metrics.
03
Discord pings you the moment something breaks. Deep Inspect shows you exactly where.
Built with
FastAPINext.jsPostgreSQLRedisDockerPrometheusGrafana
Create an account, add your first endpoint, and watch the checks roll in.
Get started — it’s free