Website Speed Test
Server/network timing — DNS, TCP, TLS, redirects, and time to first byte. Doesn't measure full-page rendering, JavaScript execution, or Core Web Vitals.
Server/network timing from WebsiteDown's probe location. It checks DNS lookup, TCP connection, TLS handshake, redirects, status code, and time to first byte.
It does not measure full-page rendering, JavaScript execution, images, layout, or Core Web Vitals.
What we measure
Every test records a request waterfall: DNS lookup, TCP connection, TLS handshake, redirects, status code, and time to first byte. The bar chart in the result above shows you which stage is the bottleneck.
How long it takes to resolve the domain to an IP address. Slow DNS often points to your DNS provider, not the site itself.
Time to open a TCP connection to the server. Reflects raw network distance and current server load.
Negotiating HTTPS encryption. Older protocols, oversized certificates, or distant servers slow this down.
How fast the server starts replying once the request is in. The single best signal of server-side speed.
Frequently asked
Time to First Byte — how long the server takes to start sending its response after receiving the request. The single most useful number for answering "is the server slow?". It excludes the time to download the rest of the page.
Under 200ms TTFB is excellent (grade A). Under 500ms is good (B). Above one second usually means the server has work to do — slow database queries, missing caches, or distant infrastructure between you and the origin.
Common causes include slow database queries, missing cache for HTML or API responses, cold serverless functions, expensive server-rendered pages, third-party APIs called during server rendering, or an origin server far from the probe location. The waterfall above shows which stage is the bottleneck — DNS, TCP, TLS, or TTFB.
No. We measure the network handshake and server response only — the time it takes the server to start replying. Tools like PageSpeed Insights and Lighthouse measure how long the page takes to render in a real browser, which includes images, JavaScript, and CSS.
PageSpeed Insights focuses on full web-page performance and Lighthouse-style browser diagnostics. WebsiteDown measures the server connection and first byte only, so it also works well for APIs and endpoints that don't render pages.
Cache aggressively, put a CDN in front of static assets, choose a host close to your users, optimise the slowest backend operation (usually a database query), and prefer modern HTTP (HTTP/2 or HTTP/3). For TTFB specifically, look at the server's work — caching the response is the fastest win.
Check live status of popular services
Speed varies; outages are binary. If a service feels slow, it may also be down for others.