My emails land in spam
Start with the receiving server’s authentication results, then review the sending service and the recipient provider’s diagnostics.
53 free tools for people who run websites
Check, fix and configure your website
Look up DNS records, test your email setup, inspect SSL certificates and follow redirects. Every check tells you what it found and what to change.
Start with the problem you have
Run these in order. Each one rules out a cause.
“Too many redirects”
Two rules are sending visitors back and forth. Find the hop where the URL repeats, then remove one of the rules.
I changed DNS and nothing happened
See what the domain's nameservers say, then compare it with what public resolvers have cached.
The browser says “Not secure”
Usually an expired certificate, one that does not cover this hostname, or a missing intermediate certificate.
Is it down or is it me?
Check the site from our server, then look at what your own connection can reach.
Want the full explanation?
Our guides walk through common problems step by step and link to the tool that confirms each fix.
Read the guidesGood places to start
Six tools that cover the most common website problems.
See the A, AAAA, CNAME, MX, TXT, NS, SOA and CAA records for any domain.
Validate an SPF record and count its DNS lookups against the limit of 10.
Check a certificate's expiry, covered names, chain and supported TLS versions.
Follow a URL through every redirect and spot loops, HTTP downgrades and long chains.
Find the registrar, key dates, status codes and nameservers of a domain.
Build or explain a cron schedule and see the next run times in your server's time zone.
Browse by category
- DNS and DomainsLook up records, follow a DNS change and inspect domain registration and expiry details. DNS Lookup · DNS Propagation Checker · WHOIS Lookup 9
- EmailCheck and build MX, SPF, DKIM and DMARC records for mail routing and sender authentication. MX Lookup · SPF Checker · DKIM Checker 7
- SSL and SecurityInspect certificates and the security headers your server sends to browsers. SSL Checker · Security Headers Checker · SSL Issuance & Renewal Debugger 5
- HTTP and RedirectsFollow redirects, read response headers and check status codes for one URL or many. Redirect Checker · HTTP Status Checker · HTTP Header Viewer 12
- Technical SEOTest crawler rules and review the tags search engines and social sites read from a page. Robots.txt Tester · Meta Tag Checker · XML Sitemap Validator 7
- Config GeneratorsBuild cron schedules, robots.txt files and redirect rules you can paste straight into your server. Robots.txt Generator · Cron Expression Builder · .htaccess Redirect Generator 6
- Network and IPSee your public IP, look up any IP address, test open ports and check whether a site is down. What Is My IP · IP Lookup · Is It Down? 7
Troubleshooting guides
Step-by-step fixes for common problems, each linked to the tool that confirms it worked.
- SSLHTTPS warning after a site move: DNS, certificates and redirects5 min
- HTTPInvestigate a 403, 404, 502 or 504 website response5 min
- Technical SEOA page is crawlable but not indexed: what to check5 min
- EmailSet up email DNS while preserving working mail5 min
- NetworkWhy a TCP port checker reports closed or timed out5 min
- RedirectsFix ERR_TOO_MANY_REDIRECTS: find and break a redirect loop7 min
- EmailEmails going to spam? Check SPF, DKIM and DMARC in this order9 min
- DNSDNS change not showing up? How propagation really works6 min
- Server configCron job not running? Seven things to check6 min
How NosHost tools work
Results explain the fix
Warnings say what is wrong, why it matters and what to change, with config you can copy.
No account needed
Run any tool without signing up. Generators and the header analyzer work entirely in your browser.
One tool leads to the next
After a check, the next useful tool opens with your domain already filled in.