demo · v132

Early hints: 103 first, 200 later

The whole reason the field exists. Simulate a server that emits HTTP/1.1 103 Early Hints, the browser preloads CSS, and the final 200 OK arrives later. responseStart now tracks the 200; firstResponseHeadersStart tracks the 103. Drag the slider to see the gap widen.

responseStart (pre-132 + 132+)

—
timing of final headers - reverted to its pre-Early-Hints meaning

firstResponseHeadersStart (new)

—
whatever headers came first - including 103

  


  

    
see also