Free DevOps & Monitoring Tools
Browser-based tools for developers, sysadmins, and SREs. No signup, no install, no tracking.
Cron Expression Builder
Build cron expressions visually. Select fields, use quick presets, and preview the next 5 scheduled runs.
Open tool →Cron Expression Validator
Paste a cron expression and see whether it's valid, what it means in plain English, and when it fires next.
Open tool →Cron Timezone Converter
See how your cron schedule translates across timezones. Compare upcoming runs in UTC, EST, CET, JST, and more.
Open tool →Cron Expression Examples
Browse 400+ ready-to-use cron expressions organized by category. One click to copy any schedule.
Open tool →Cron Job Calculator
Calculate how many times your cron job runs per hour, day, week, month, and year.
Open tool →Uptime Calculator
Convert uptime percentages (99.9%, 99.99%) to allowed downtime per day, month, and year.
Open tool →SSL Certificate Checker
Inspect any domain's SSL certificate: issuer, expiry date, SANs, signature algorithm, and chain details.
Open tool →Domain WHOIS Lookup
Look up domain registration details: registrar, creation date, expiry, nameservers, and DNSSEC status.
Open tool →HTTP Status Checker
Send a request to any URL and see the HTTP status code, response headers, redirect chain, and timing.
Open tool →Port Checker
Test whether a specific TCP port is open on a remote host. Useful for firewall and service diagnostics.
Open tool →Response Time Tester
Measure how long a URL takes to respond. See DNS, connect, TLS, and total time breakdowns.
Open tool →DNS Lookup
Query DNS records for any domain: A, AAAA, CNAME, MX, TXT, NS, and SOA records.
Open tool →MX Record Lookup
Check the mail exchange (MX) records for a domain and see which mail servers handle its email.
Open tool →HTTP Headers Checker
View the full list of HTTP response headers returned by any URL. Check security headers, caching, and CORS.
Open tool →Downtime Cost Calculator
Estimate how much every hour of downtime costs your business in lost revenue and wasted productivity.
Open tool →Monitoring ROI Calculator
Compare monitoring costs against downtime losses. See how fast monitoring pays for itself.
Open tool →SSL Expiry Countdown
Enter any domain to see exactly how many days and hours until its SSL certificate expires.
Open tool →Redirect Chain Checker
Trace the full redirect chain for any URL. See every hop, status code, and response time.
Open tool →Security Headers Checker
Analyze HTTP security headers and get a letter grade. Check for HSTS, CSP, X-Frame-Options, and more.
Open tool →Website Down Checker
Check if a website is down for everyone or just you. Get status code, response time, and server IP.
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