Blocked

Time spent queued before the browser could even open a connection for this request.

The browser had somewhere to send this request but did not start yet, usually because it was waiting on a free connection to that host, on a higher-priority request ahead of it, or on the cache to decide whether a revalidation was needed. A large blocked time on many requests to the same host is usually a connection-limit problem, not a server problem: the fix is fewer requests to that host, not a faster one.

Other timing phases

• DNS — Time spent resolving the hostname to an IP address.
• Connect — Time spent establishing the TCP connection, including the TLS handshake for HTTPS.
• SSL / TLS handshake — The portion of connect time spent negotiating TLS, shown separately for inspection.
• Send — Time spent writing the request onto the wire.
• Wait (TTFB) — Time between the request finishing transmission and the first byte of the response arriving.
• Receive — Time spent reading the response body after the first byte arrived.