2026-05-12
We investigated a bug where CUBIC's congestion window became pinned at its minimum floor, causing a performance to plummet. The fix involved correctly measuring idle periods to distinguish RTT wait times from actual application idleness....
2025-10-29
We identified and patched two DDoS vulnerabilities in our QUIC implementation related to packet acknowledgements. Cloudflare customers were not affected. We examine the "Optimistic ACK" attack vector and our solution, which dynamically skips packet numbers to validate client behavior. ...
2025-08-22
Media over QUIC (MoQ) is a new IETF standard that resolves this conflict, creating a single foundation for sub-second, interactive streaming at a global scale. ...
2024-12-30
h3i is a command line tool and Rust library designed for low-level testing and debugging of HTTP/3, which runs over QUIC....
2024-03-06
This blog discusses the introduction of MASQUE to Zero Trust WARP and how Cloudflare One customers will benefit from this modern protocol...
2023-06-20
Today, Cloudflare is very excited to announce full support for HTTP/3 Extensible Priorities, a new standard that speeds the loading of webpages by up to 37%...
2023-06-06
With the HTTP/3 RFC celebrating its 1st birthday, we examined HTTP version usage trends between May 2022 - May 2023. We found that HTTP/3 usage by browsers continued to grow, but that search engine and social media bots continued to effectively ignore the latest version of the web’s core protocol...
2022-06-06
HTTP/3 is now RFC 9114. We explore Cloudflare's view of how it is being used...
2022-03-20
We continue our technical deep dive into traditional TCP proxying over HTTP...
2021-11-15
The ability to make TCP and QUIC client connections from within Workers and Durable Objects, as well as the ability to connect to Workers over TCP and QUIC without using HTTP, will be coming to Cloudflare Workers. Here’s a peek at what we’re working on....
2021-10-20
It is now possible to connect a Cloudflare Tunnel to the Cloudflare network with QUIC. While doing this, we ran into an interesting connectivity problem unique to UDP. ...
2021-05-28
QUIC is a new fast and secure transport protocol. Version 1 has just been published as RFC 9000 and today Cloudflare has enabled support for all customers, come try it out. ...
2021-03-20
How we use gRPC in combination with Kubernetes to improve the performance and usability of internal APIs....
2020-10-22
QUIC and HTTP/3 are open standards that have been under development in the IETF for almost exactly 4 years. On October 21, 2020, following two rounds of Working Group Last Call, draft 32 of the family of documents that describe QUIC and HTTP/3 were put into IETF Last Call....
2020-06-30
Now that Firefox Nightly supports HTTP/3 we thought we'd share some instructions to help you enable and test it yourselves....
2020-05-08
Congestion control and loss recovery play a big role in the QUIC transport protocol performance. We recently added support for CUBIC and HyStart++ to quiche, the library powering Cloudflare's QUIC, and lab-based testing shows promising results for performance in lossy network conditions....
2020-04-14
We announced support for HTTP/3, the successor to HTTP/2, during Cloudflare’s birthday week last year. Our goal is and has always been to help build a better Internet. Even though HTTP/3 is still in draft status, we've seen a lot of interest from our users....
2020-01-14
At Cloudflare, we develop protocols at multiple layers of the network stack. In the past, we focused on HTTP/1.1, HTTP/2, and TLS 1.3. Now, we are working on QUIC and HTTP/3, which are still in IETF draft, but gaining a lot of interest....
2020-01-08
Significant work has gone into optimizing TCP, UDP hasn't received as much attention, putting QUIC at a disadvantage. Let's explore a few tricks that help mitigate this....
2019-11-20
One of the more interesting features introduced by TLS 1.3, the latest revision of the TLS protocol, was the so called “zero roundtrip time connection resumption”, a mode of operation that allows a client to start sending application data, such as HTTP requests...
