Why Quic Might Kill Tcp for Good
Key topics
QUIC + HTTP/3 has been “the future” for a while, but until now most deployments were edge cases or just browsers quietly switching protocols under the hood. Media delivery is different, it stresses latency, congestion control, retransmissions, and real-time resilience in ways that show off QUIC’s strengths.
A few things that make me think TCP’s days are numbered (at least for large-scale internet workloads):
QUIC’s user-space implementation means iteration speed that TCP will never match.
Built-in multiplexing avoids the classic “TCP head-of-line blocking” problem.
Encryption as the baseline, not the addon.
Congestion control that works better for streaming and real-time traffic.
If the economics work out for Cloudflare and others, media over QUIC could be the wedge that normalizes QUIC everywhere — not just browsers, but infra, APIs, and even enterprise backends.
Curious if anyone here is already seeing QUIC make TCP irrelevant in production workloads (beyond web browsers)? Or is TCP going to stick around longer than we think, the way IPv4 has?
Cloudflare's media CDN built on QUIC may signal the decline of TCP due to QUIC's advantages in latency, congestion control, and encryption.
Snapshot generated from the HN discussion
Discussion Activity
Light discussionFirst comment
36m
Peak period
2
0-3h
Avg / period
1.5
Key moments
- 01Story posted
Aug 22, 2025 at 3:31 PM EDT
5 months ago
Step 01 - 02First comment
Aug 22, 2025 at 4:08 PM EDT
36m after posting
Step 02 - 03Peak activity
2 comments in 0-3h
Hottest window of the conversation
Step 03 - 04Latest activity
Aug 24, 2025 at 11:59 AM EDT
5 months ago
Step 04
Generating AI Summary...
Analyzing up to 500 comments to identify key contributors and discussion patterns
Want the full context?
Jump to the original sources
Read the primary article or dive into the live Hacker News thread when you're ready.
But I wonder... if QUIC does end up entirely supplanting TCP, that means it's an entirely different networking scheme. We'd no longer be using TCP/IP at all, but something else. QUIC/IP?
I agree with this and would add that the HN crowd is very HTTP browser and API centric. There are hundreds of thousands of applications that will be using TCP and not be updated until the internet is shut off. This is especially true for B2B applications. Just getting them to update cipher protocols is like pulling teeth, each time. There are an amazing number of "business critical" applications that are running ancient libraries, protocols, etc...
TCP and UDP will never go away but browsers and some API libraries may stop using TCP. More likely additional Layer 7 protocols may get added to TCP and UDP and people will use what works best for their application needs.
Do you know of any examples of these "walking wounded" applications? Can we bring some attention to reduce their foot print.
More useful is finding newer, supported and open source applications that can replace their functionality but that's a whole other topic around prioritization and people paralyzed by fear of change due to the amounts of money flowing through their unsupported applications.
So how relevant are the benefits you listed (faster development, multiplexing, congestion control) for residental end points? I am sceptical.