xxviii · x · mmxxvi

Hello, again

I codify contracts between systems for a living, in Rust and Python. I once spent five years chasing where the antimatter went.

Senior software engineer at PactFlow (SmartBear). I help lead the open-source Pact Foundation and maintainpact-python; I also wrote tikz-feynman,rust-skiplist, and more.

Previously: data and cloud engineering at KPMG, and doctoral research in theoretical particle physics.

The year in code

5242 commits, 818 PRs, and 276 issues across 37 repositories.

Oct 2025 — Oct 2026
Most of what I make is open. Each square below is one day of my GitHub contributions over the past year.

Latest commits

JP-Ellis/rust-skiplistrefactor: keep the concat bookkeeping in one place1d
JP-Ellis/rust-skiplistrefactor: share the Equal-as-Less comparison1d
JP-Ellis/rust-skiplistrefactor: share the appending extend loop1d
JP-Ellis/rust-skiplistrefactor(node): drop the visitor step method1d
JP-Ellis/rust-skiplisttest(node): check traverse against the step loop2d
JP-Ellis/rust-skiplisttest(bench): add opt-in large-payload workloads2d

Latest issues & PRs

JP-Ellis/rust-skiplist[PR · open]
test: trim slow tests under Miri19h
JP-Ellis/rust-skiplist[PR · merged]
perf: tighten node walks and drop O(n) scans2d
JP-Ellis/rust-skiplist[PR · merged]
test: add hot-path benchmarks and a release CI job2d
JP-Ellis/rust-skiplist[PR · merged]
perf(node): lay out node fields hot-first2d

Selected projects

pact-pythonOSS · libraryPython bindings for Pact, rebuilt over a Rust FFI core. Downloaded over 1.3 million times a month.↗ github
tikz-feynmanOSS · LaTeXA LaTeX package for typesetting Feynman diagrams with TikZ; adopted across particle physics with 400+ academic citations.↗ github
rust-skiplistOSS · libraryA skip list for Rust.↗ github
↗ All projects