Check any website's speed, hosting, SSL and DNS
One domain, one report: who hosts it, how fast the server answers, whether the certificate, DNS and redirects are healthy, and what to fix first.
Free, no signup, nothing stored. Five checks in a few seconds.
9 free tools, grouped by the question they answer
Performance
How fast it loads, and why.
Hosting & setup
Who runs it and how it's wired.
Reliability
Is it up, trusted and resolving?
How the web's biggest sites are hosted
Hosting, CDN and DNS for 136 well-known websites, read from public signals.
- netflix.comNetflix Streaming Services Inc. network
- nytimes.comBehind Fastly (origin hidden)
- reddit.comBehind Fastly (origin hidden)
- openai.comBehind Cloudflare (origin hidden)
- techcrunch.comAutomattic
- github.comGitHub
- shopify.comBehind Cloudflare (origin hidden)
- wikipedia.orgWikimedia Foundation Inc. network
- notion.soVercel
- stripe.comAmazon AWS network
- backlinko.comNetlify
- pinchofyum.comAmazon AWS network
- spotify.comBehind Fastly (origin hidden)
- wired.comBehind Cloudflare (origin hidden)
- allbirds.comShopify
- neilpatel.comWP Engine
Hosts that held up under load
Hosting reviews are mostly opinion. Load tests aren't: these hosts earned Top Tier in Review Signal 2026, an independent benchmark where they kept 99.9%+ uptime and showed virtually no signs of struggle under load (error rates at or below 0.1%, responses under 1 second).
See the benchmark resultsTop Tier · Review Signal 2026
PressableTop Tier ×4from $20.83/mo
BluehostTop Tier ×3from $3.99/mo
GreenGeeksTop Tier ×2from $2.95/mo
DreamHostTop Tierfrom $1.99/mo
×N = Top Tier in N of the study's price tiers. Source: Review Signal WordPress Hosting Performance Benchmarks 2026 ↗. Prices are the hosts' own advertised entry rates.
Fix it, step by step
- How to fix a slow TTFB: server-side fixes that actually workSlow Time to First Byte is a server or network problem, not a page problem. Find the slow phase, then fix it with caching, a CDN, database work or hosting.
- How to check DNS propagation (and why it takes so long)Check DNS propagation by comparing public resolvers with your authoritative nameservers. Learn how TTL sets the timing and why changes seem stuck for hours.
- Why is my website down? How to find the cause, step by stepFind out why your website is down: check if it's down for everyone, decode the error, and test the domain, DNS, SSL and server in the order that saves time.
- SSL certificate expired? What happens and how to fix it fastAn expired SSL certificate triggers a full-page browser warning. See how to renew it, fix chain errors, why auto-renewal fails, and the new 200-day limit.
- ERR_SSL_PROTOCOL_ERROR: what it means and how to fix itERR_SSL_PROTOCOL_ERROR means the secure handshake failed before the page loaded. How to tell if it's the server or your device, and the fixes for each.
- Your connection is not private: NET::ERR_CERT_DATE_INVALID fix"Your connection is not private" means the certificate failed a check: expired, wrong name, incomplete chain or a wrong clock. How to find which and fix it.
Fair questions
What does the website checker test?+
Five checks run at once: who hosts the site (from its headers, IP network and nameservers), how fast the server sends its first byte, the SSL certificate's validity and grade, whether public DNS resolvers agree, and whether redirects and HTTPS are set up cleanly. A Core Web Vitals speed test is one click further.
Is it free?+
Yes. Every tool runs without signup or payment, and results aren't stored. Run as many checks as you like.
How accurate are the results?+
Speed tests use the Google PageSpeed Insights engine (lab runs plus real-visitor field data where it exists). Server-side checks — hosting, TTFB, DNS, SSL, redirects, uptime — are real requests made at the moment you run them, so they show the live state of the site.
How does this site make money?+
Affiliate links. When a result points at hosting or services, some links are affiliate links — marked where they appear, with commissions that never change a measurement or an ordering. Privacy & disclosure.
What's a good server response time (TTFB)?+
Under roughly 300 ms is good and over roughly 800 ms is slow; Google's own threshold for a good TTFB is 800 ms at the 75th percentile of real visits. The TTFB guide covers the details.