Response Time Tester
Measure DNS, connection, TLS, TTFB, and download time for any URL.
AWS 
Shopify Free Website Speed Test
Understanding where latency comes from is the first step to fixing slow websites. This free response time tester breaks down every phase of an HTTP request so you can pinpoint the bottleneck:
DNS Lookup resolves the domain name to an IP address. Slow DNS can add hundreds of milliseconds before your server even sees the request. TCP Connect establishes the network connection. TLS Handshake negotiates encryption for HTTPS connections. Time to First Byte (TTFB) measures how long the server takes to start sending a response after receiving the request — this is the strongest indicator of backend performance. Download is the time to transfer the full response body.
What is TTFB?
Time to First Byte (TTFB) is the duration from when the client sends the request to when it receives the first byte of the response. A TTFB under 200ms is considered fast, 200–500ms is acceptable, and anything above 600ms may indicate server-side performance issues. TTFB is influenced by server processing time, database queries, and geographic distance between client and server.
Need Continuous Monitoring?
A one-time speed test gives you a snapshot, but performance fluctuates throughout the day. ServiceAlert.ai monitors 695+ cloud services 24/7 and sends instant alerts via email, Slack, Teams, Google Chat, or Discord when degradation or outages occur.