Free Website Tools

14 free tools and plugins for developers, sysadmins, and website owners — DNS, SSL, security headers, WHOIS, speed test, WordPress monitoring, and more. No signup required.

Featured

Website Health Score

Free multi-check grade across 5 categories — uptime, SSL, DNS, security headers, and performance. Enter any URL and get an instant A+ to F score with actionable recommendations. No signup required.

Use this tool
Free Plugin

WordPress Site Monitor Plugin

Free plugin that monitors your WordPress site from the inside — detecting file injections, rogue admin users, foreign-language content, brute force attacks, security misconfigurations, and more. No inbound ports. Works behind Cloudflare.

Use this tool
New

AI SEO Checker

Is your website visible to ChatGPT, Perplexity, Claude, and Gemini? Get your AI readiness score, audit crawler access, generate your llms.txt, and see where to submit your site.

Use this tool
Popular

SSL Certificate Checker

Check any SSL certificate instantly. See issuer, expiry date, days remaining, TLS version, and chain validity. Color-coded warnings for expiring certificates.

Use this tool

DNS Lookup

Look up A, AAAA, MX, NS, TXT, CNAME, and SOA records for any domain. Instant results with response time. No signup required.

Use this tool

WHOIS Lookup

Look up domain registration details, expiry date, registrar, nameservers, and RDAP data for any domain.

Use this tool

Security Headers Checker

Check your website's security headers — HSTS, CSP, X-Frame-Options, CORS, Referrer-Policy, and more. Get a letter grade with missing header details.

Use this tool

SPF & DMARC Checker

Check your domain's SPF and DMARC email authentication records. See if your domain is protected against email spoofing and phishing.

Use this tool

HTTP Status Code Checker

Check any URL's HTTP response code, follow redirect chains, and inspect response headers. See 200, 301, 404, 500 and everything in between.

Use this tool

Redirect Chain Checker

Trace the full redirect chain for any URL. Detect redirect loops, excessive hops, and SEO-damaging 302 redirects.

Use this tool

Port Checker

Check if any TCP port is open on any host. Test SSH, HTTP, HTTPS, SMTP, MySQL, PostgreSQL, Redis, and custom ports.

Use this tool

robots.txt Checker

Fetch and analyse the robots.txt file for any website. See all rules, detect Googlebot blocks, missing sitemaps, and crawl issues.

Use this tool

Blacklist Checker

Check if your domain or IP is listed on major email blacklists — Spamhaus, SpamCop, Barracuda, SORBS, and more. Identify deliverability problems instantly.

Use this tool

Website Speed Test

Test your website's speed. Measure TTFB, total load time, page size, compression, and CDN cache status. Get a grade and actionable performance tips.

Use this tool

Uptime & SLA Calculator

Calculate allowed downtime for any uptime percentage. See how much downtime 99.9%, 99.99%, and other SLA levels actually mean in real time.

Use this tool

Browse by category

Each category landing groups the relevant free tools, explains what they catch, and links to the matching continuous monitor types.

Uptime & Performance

Status checker, speed test, health score, SLA calculator.

Website Security

SSL chain, security headers, blacklist, port checker.

DNS & Email

DNS lookup, WHOIS, SPF/DMARC authentication checker.

AI & SEO

AI SEO Checker, redirect chains, robots.txt audit.

Turn any tool into a continuous monitor

Each free tool above maps to a continuous monitor type. Set it up once, get alerted whenever the result changes:

HTTP uptime monitoring
Continuous version of the HTTP Status Checker.
SSL certificate monitoring
Continuous version of the SSL Certificate Checker.
DNS record monitoring
Continuous version of DNS Lookup.
Security headers monitoring
Continuous version of the Security Headers Checker.
SPF/DMARC monitoring
Continuous version of the SPF & DMARC Checker.
Blacklist monitoring
Continuous version of the Blacklist Checker.
Redirect chain monitoring
Continuous version of the Redirect Chain Checker.
Response time monitoring
Continuous version of the Website Speed Test.
Got questions?

Frequently asked questions

Everything you need to know about Uptrue — no fluff.

Are all of these tools really free?
Yes. Every tool on this page runs in your browser against our edge network — no signup, no email capture, no rate limit beyond basic abuse protection. You can run them on any public URL as many times as you want, and the results are shareable.
Each tool gives you a snapshot — the state of your site, certificate, or DNS records at the moment you click "check". Continuous monitoring runs the same checks every minute (or every 5 minutes) and alerts you the moment something changes. The Free Uptrue plan includes 3 continuous monitors with email alerts.
Run the Website Health Score — it bundles the five most important checks (uptime, SSL, DNS, security headers, performance) into a single A+ to F grade. It is the fastest way to spot what to fix first. From there, drill into individual tools (SSL Checker, Security Headers Checker, etc.) for the failing categories.
No. Tool results are computed on-demand and never persisted to a user account or shared with third parties. We may keep aggregate, anonymised counts for capacity planning, but never your specific URLs or results.
Not yet — the tools are designed for one-off ad-hoc checks. If you need a permanent live status indicator, set up a public status page on the Free or Lite plan, or embed the badge from the Uptime Leaderboard if your site qualifies.
The browser tools check externally — what the public internet sees. The Uptrue WordPress plugin checks from inside your site, with privileged access to detect things external tools cannot: file injections, rogue admin users, plugin CVEs, brute force attacks, and security misconfigurations. The two are complementary.

Monitor your website 24/7

Go beyond one-time checks. Get continuous monitoring with instant alerts. The Free plan includes 3 monitors — no credit card required.

Start Monitoring Free