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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

4736 commits, 732 PRs, and 270 issues across 35 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/JP-Ellisdocs: add GitHub profile README18h
pact-foundation/pact-gofix: enable resource, type safety and gosec linters (#613)1d
JP-Ellis/dotfilesfix(nvim): open neogit pull requests from the push remote1d
JP-Ellis/dotfilesfix(git): inherit tracking from the start branch1d
JP-Ellis/borrow-checkertest(e2e): count main's Costco payee in the value suggestions1d
JP-Ellis/borrow-checkertest(e2e): expect query-text chips in the top-bar layout spec1d

Latest issues & PRs

JP-Ellis/dotfiles[PR · merged]
feat(rustic): exclude reinstallable tools and application caches15h
pact-foundation/pact-go[PR · merged]
fix: keep every value of a multi-value header20h
JP-Ellis/borrow-checker[PR · merged]
docs: correct lines that removed crates, tasks and fixes made wrong1d
JP-Ellis/dotfiles[PR · merged]
fix(general): set BROWSER to `open` on macOS1d

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