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From belderbos.dev × Refactor Coaching

Build a Production
Rust Library in 6 Weeks

Do you want to go from exercises to building something real? Go deeper in a small, coached cohort — build a JSON parser from scratch, wire it into Python with PyO3, and benchmark it against CPython.

6 weeks · ~10 hours/week · capped at 6 developers · led by Bob Belderbos & Jim Hodapp.

See the full cohort & apply →

Full curriculum, pricing, and enrollment at scriptertorust.com

What You'll Build

A complete, blazingly-fast JSON parser in Rust, callable from Python — reviewed line by line via GitHub PRs.

Parser from scratch

Tokenizer, recursive descent parser, full JSON spec. Enums, pattern matching, ownership, borrowing — learned by building, not reading.

PyO3 Python integration

The same FFI layer behind Pydantic and Polars. Create Python bindings, handle cross-language memory, and import your Rust code in Python.

Benchmarked performance

Measure your parser against Python's json module. Profile bottlenecks, optimize hot paths, and understand why Rust is fast.

Real Results From Real Cohort Members

After 6 weeks, Josh Engroff's Rust JSON parser beats CPython's stdlib json on every fixture in his benchmark suite.

2.96×
canada.json
2.3 MB · float-heavy · vs CPython stdlib
1.82×
citm_catalog.json
1.7 MB · structured · vs CPython stdlib
1.42×
twitter.json
631 KB · unicode + escapes · vs CPython stdlib

Built from scratch in 6 weeks while reviewed weekly via GitHub PRs.

Your Coaches

Jim Hodapp

Jim Hodapp

Seasoned Rust developer, open source contributor, and engineering coach with 20+ years of experience — from GNOME and Ubuntu to embedded systems and startups. Mentors developers through Refactor Coaching.

Developer coach and builder with 10+ years at Sun/Oracle and 6+ years coaching. Co-founded Pybites and built its Python and Rust platforms (500+ exercises), 150+ developers coached. Brings the Python perspective and coaches on bridging Python and Rust.

Ready to build a real Rust library?

See the full curriculum, the coaches, pricing, and dates — and book a call to find out if it's the right fit.

Explore the cohort at scriptertorust.com →

Log in to join the waitlist and we'll email you when the next cohort opens.