Wait (TTFB)

Time between the request finishing transmission and the first byte of the response arriving.

This is "time to first byte," and it is the phase that actually measures server-side work: routing, database queries, template rendering, anything the backend does before it starts writing a response. Network round-trip time is part of it too, so the same backend will show a larger wait time to a client on a slow or distant connection even if it did identical work.

Other timing phases

• Blocked — Time spent queued before the browser could even open a connection for this request.
• 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.
• Receive — Time spent reading the response body after the first byte arrived.