Fun facts

The .bleep file

A 40-byte file at the repository root called .bleep. It's an internal Cloudflare CI marker — its contents bump the CI version. Worth knowing about if you're confused why a tiny file with no extension lives next to Cargo.toml.

TinyUFO is the cache behind the cache

pingora-memory-cache is the user-facing async memory cache, but the algorithm doing the actual admission and eviction work is in a separate crate called tinyufo (TinyLFU + S3-FIFO flavor). It's the only crate in the workspace that doesn't carry the pingora- prefix. The README calls it out specifically.

"Pingora" the name

The README never explains where the name comes from. The Cloudflare blog post that announced the open-source release (blog.cloudflare.com/pingora-open-source) hints at it being a constructed word. The codebase doesn't reveal more.

Four TLS backends

Pingora supports OpenSSL, BoringSSL, s2n-tls, and rustls. Each is a separate crate (pingora-openssl, pingora-boringssl, pingora-s2n, pingora-rustls) and they are mutually exclusive cargo features. The rustls integration carries this warning verbatim in pingora/Cargo.toml:

## Use [rustls](https://crates.io/crates/rustls) for tls
##
## ⚠️ _Highly Experimental_! ⚠️ Try it, but don't rely on it (yet)

That's two unicode warning signs and the word "Highly" in italics. Few open-source projects communicate experimental status with quite that much commitment.

Edward Wang's commit count

Top committer Edward Wang has made 135 commits — about 23% of the 598 public commits, more than the next two combined. Most of his work is on the cache layer and HTTP/2 proxy code paths.

A README banner

The README opens with ![Pingora banner image](./docs/assets/pingora_banner.png). The asset is in the repo. Not many high-performance proxies have a banner.

"More than 40 million requests per second"

The README's tagline. For context: that's about 3.5 trillion requests per day. The number is a few years old at this point and is almost certainly higher in production now.

Battle-tested before "open source"

The first public commit is dated 2023-05-08 but the repo only saw real activity from February 2024 onward. The intervening eight months are the gap between Cloudflare deciding to open-source and actually preparing the code for public release. The internal version had been running for several years before that.