Tools
Free utilities I use day-to-day, available for anyone.
Check the SSL/TLS certificate expiry date for any domain.
Query A, AAAA, MX, TXT, NS and CNAME records for any domain.
Calculate network, broadcast, and host ranges for an IPv4 address.
Inspect certificate issuer, validity period, and remaining days.
Plan subnets and view CIDR breakdowns for IPv4 networks.
Check which common service ports are open on a host.
Look up domain registration details via RDAP.
Estimate monthly cost across on-demand, reserved, and spot pricing.
Estimate monthly S3 storage and request costs by storage class.
Compare resource requests vs actual usage and estimate savings.
An interactive checklist to identify common cloud cost waste.
Check HTTP status code, response latency, and headers for any URL.
Run on-demand health checks across multiple URLs.
Highlight errors, warnings, and HTTP status patterns in pasted logs.
Common Prometheus queries and function reference.
Get a unique URL to inspect incoming webhook requests.
Convert between JSON and YAML formats instantly.
Encode, decode, and hash text in your browser.
Run basic best-practice checks on a Dockerfile or K8s manifest.
Build, explain, and preview the next runs of a cron expression.