Master transport‑layer improvements that affect page delivery in 2025. Learn how HTTP/3 over QUIC changes latency, reliability, and rollout tactics.
What transport does HTTP/3 use in 2025?
QUIC over UDP
SCTP without encryption
Raw IP over ICMP
TCP with TLS 1.2 only
Which issue does QUIC address more directly than HTTP/2 over TCP?
Head‑of‑line blocking at the transport layer
JavaScript execution order
CSS cascade priority
HTML parsing quirks in browsers
What handshake optimization can reduce time to first byte on repeat visits?
Server push for all assets
Forcing HTTP/1.1 keep‑alive off
Disabling TLS entirely
0‑RTT connection resumption in QUIC/TLS 1.3
Which deployment approach best accelerates HTTP/3 gains across global traffic?
Only add Preconnect links to origins
Serve QUIC from a single regional PoP
Enable HTTP/3 at the edge/CDN with server support and measure
Set a meta tag to upgrade protocols
Which statement about encryption is correct for HTTP/3?
TLS 1.0 is required for compatibility
Encryption is mandatory; HTTP/3 uses TLS 1.3 integrated with QUIC
Encryption is optional to save CPU
Certificates are not needed for QUIC
Which measurement expectation is most realistic when enabling HTTP/3?
A universal 50% reduction in INP
Identical performance on mobile and desktop
Latency improvements vary by network conditions and endpoints
Guaranteed TTFB under 100 ms everywhere
Which header/protocol signal confirms a successful HTTP/3 negotiation?
A meta http‑equiv pragma
A Cache‑Control: immutable directive
A Link: rel=preload header on CSS
ALPN showing h3 in the TLS handshake
Which migration pitfall most commonly undermines HTTP/3 gains?
Serving WebP images
Using Brotli compression
Leaving origin behind a TCP‑only load balancer
Inlining small CSS
Which statement best reflects 2025 adoption trends for QUIC?
Adoption has stalled since 2021
QUIC is being retired in favor of SPDY
QUIC usage continues to expand across the public Internet
Only browsers support QUIC; CDNs do not
What should teams monitor after enabling HTTP/3?
Protocol mix, handshake errors, and user‑centric metrics (TTFB, INP)
Only crawl stats in XML sitemaps
Meta keywords frequency
H1 count per page
Starter
You understand the basics of HTTP/3. Roll out at the edge and validate gains under real network conditions.
Solid
Strong progress. Audit end‑to‑end QUIC paths and monitor ALPN, TTFB, and INP for sustained wins.
Expert!
Excellent. You’re measuring protocol mix and optimizing for variable networks to maximize QUIC’s benefits.
