Free website & uptime tools
No signup needed. Check an SSL certificate, DNS records or a domain, run a real browser check, see if a site is down from 22 locations, or work out downtime and SLA budgets.
Free Browser Check
NewLoad any URL in a real headless browser and see a screenshot plus Core Web Vitals (LCP, CLS, FCP, TTFB) — the way your users actually experience the page.
SSL, DNS and domain tools
Look up a certificate, a DNS record or a registration. Results come live from our servers, from public resolvers and from the registry.
SSL Checker
Check an SSL certificate: validity, expiry date, issuer, names covered and chain.
DNS Lookup
Look up A, AAAA, CNAME, MX, NS, TXT, SOA, CAA and PTR records on three public resolvers.
MX Lookup
Find the mail servers of a domain and their priority.
TXT Record Lookup
Read the TXT records of a domain, including SPF, DKIM and DMARC.
DNS Propagation Checker
Compare one DNS record across Cloudflare, Google and Quad9 and spot differences.
Domain Expiry Checker
See when a domain expires and how many days are left.
WHOIS Lookup
Registrar, dates, status and name servers of a domain, from RDAP.
Domain Age Checker
How old a domain is, from its registration date.
Uptime and website tools
Is This Website Down?
Check if a site is reachable from 22 locations on six continents at once.
Uptime Calculator
Turn an uptime percentage into real allowed downtime per day, week, month, and year.
SLA Calculator
Allowed downtime and error budget for any SLA target, across monthly and yearly windows.
Downtime Cost Calculator
Estimate what an outage costs your business from revenue and downtime duration.