Mathieu Soysal

Rust Software Developer
Paris, France · +33 6 52 60 01 10
[email protected]
github.com/MathieuSoysal · mathieusoysal.dev
linkedin.com/in/mathieusoysal
2,300+ downloads of my Rust CLI on crates.io ~45k lines of Rust across 10+ projects Top 1% of 320,000 on CodinGame, in Rust 600+ repositories use my Javadoc Publisher GitHub Action

Profile

Software developer specialized in Rust, with a test-first, tooling-heavy engineering culture: benchmarks in CI, mutation testing, fuzzing, security audits. Author of CG Bundler, a Rust CLI published on crates.io, and of GitHub Actions adopted by third-party projects. Systems-programming foundation from 42 (C, Unix processes and signals, x86-64 assembly) on top of a computer-science degree — at home in performance-critical code that must stay correct and fast under a hard time budget.

Selected Rust Projects

CG Bundler — CLI published on crates.io

2025 – present · ~14k LOC
  • AST-level bundler that flattens a multi-file Rust crate into one optimized source file for competitive programming — built on syn / quote / prettyplease and cargo_metadata, with a file-watch mode (notify) and a clap CLI.
  • Shipped as a real product: v1.1.18, 2,300+ downloads, integration-test suite, CI with automated releases, cargo-deny security audits and a SonarCloud quality gate.
Codecrates.iodocs.rs

Taskmaster — Unix process supervisor (42 project)

~5k LOC
  • supervisord-style job-control daemon: process lifecycle modeled as a state machine over fork/exec/wait and POSIX signals (libc), declarative YAML configuration, interactive control shell, logging subsystem, optional ratatui TUI.
  • Robustness-focused test suite (config, FSM, logger, failure injection); coverage tracked with Codecov in CI.

Mars Lander — genetic algorithm, Rust → WebAssembly

  • Trajectory optimizer for CodinGame's Mars Lander: rayon-parallel physics simulation, criterion benchmarks, compiled to WASM (wasm-bindgen) behind an interactive browser visualizer deployed on Cloudflare Pages.

Ultimate Tic-Tac-Toe engine — cargo workspace

~6k LOC
  • Bitboard game engine with precomputed perfect-play tables; separate crates for self-play training and an MCTS visualizer; criterion benchmarks.

CodinGame contest bots — performance-critical Rust

2024 – 2026 · ~15k LOC
  • Contest AIs engineered like production code: continuous benchmarking in CI (Bencher), mutation testing (cargo-mutants), fuzz tests, Codecov, security audits — all under the contests' hard per-turn time limits.

Open Source & Other Engineering

  • Maintainer of reusable GitHub Actions since 2021, used by repositories beyond my own: Javadoc Publisher (used by 600+ repositories; 57★, 19 forks, external contributors), Jib Container Publish, Replace String In File.
  • Production web engineering on Cloudflare Workers/Pages: prerendered static sites with an edge API on KV storage, strict CSP, and 20+ automated build-time quality gates (JavaScript); Rust build tooling on a second product (Markdown SSG with pulldown-cmark, SVG rendering with resvg, WASM simulation engine).
  • Java ecosystem: Maven/Gradle builds, Jib container images, SonarCloud quality gates.

Education

42 Paris — Common Core

2023 – present
  • Peer-reviewed systems programming in C: POSIX shell (minishell), threads & synchronization (philosophers), x86-64 assembly (libasm), raw-socket ICMP (ft_ping), Docker infrastructure (Inception).

IUT — Université de Montpellier — DUT Informatique

2018 – 2022

Skills

Rust: editions 2021/2024, cargo workspaces, AST tooling (syn/quote), wasm-bindgen, rayon, serde, clap, thiserror/anyhow, criterion, cargo-deny, cargo-mutants, fuzzing

Systems: C (POSIX), processes/signals/pipes, sockets, x86-64 assembly basics, Docker, Linux

CI/CD & quality: GitHub Actions (author), SonarCloud, Codecov, Bencher, automated releases, TDD

Also: Java (Maven/Gradle, Jib), JavaScript/TypeScript, Cloudflare Workers, Git

Languages: French (native), English (B1)