Rai Butera.

Engineering
Products
Better software

Senior engineer.
Product builder.

I build products and the tools to make complex software easier to ship and review.

Explore my work Get in touch

Ideas
Systems
People

Build
Review
Ship

01 / Independent product

Rennet

Making code
review keep up.

Code
Context
Better decisions

I built Rennet to make large changes easier to understand, question, and review.

Explore Rennet

Rennet review showing engineering decisions linked to source code — Decisions, rationale, and the code behind them. An existing product capture.

The work behind the interface

Generating more code makes understanding the change more important. Rennet brings specialised review lenses and source-linked evidence into a local-first workspace, so the reasoning stays beside the work.

02 / Independent product

Chaching

Your agents run.
The meter does too.

Token spend
Cache hits
Actual receipts

A cash register for coding agents. I built Chaching to make token spend and cache costs visible, from the terminal to the receipt.

Explore Chaching

Chaching dashboard showing daily token spend and account usage — The dashboard. Spend across tools, at a glance.

Chaching sample receipt itemising token spend and cache savings — And yes, it prints a receipt.

Accounting with a point of view

Cache reads and writes still cost money. Chaching makes those details legible through a live terminal dashboard, a web view, and a shareable receipt. The screenshots show example product data.

03 / Commercial work

Built with teams.
Shipped into production.

Senior full-stack engineering

easyJet

via Focused Labs

Modernising while delivering.

Production features from the first week. React and TypeScript on the frontend, C# and .NET behind it. I helped move the codebase into Nx in reviewable steps, with shared libraries used by three frontends and a Playwright/MSW crash-detection gate.

Tech Lead / 2020–2025

LexStep

Leading a platform through change.

I led an international team through a legacy-platform overhaul: tested NestJS services, a MySQL-to-PostgreSQL migration, React adoption, and infrastructure moving from VMs and Jenkins to AWS and Terraform. The responsibility included the incidents, not just the releases.

04 / A little context

I like knowing
how things work.

And making them work better. My experience spans full-stack engineering, technical leadership, and building my own products. I care about the decisions underneath the interface as much as the interface itself.

Rennet and Chaching come from problems I run into in my own work. Building and using them keeps that feedback loop short.

Find me on GitHub

Have something in mind?

Let’s build
something good.

rai@rbutera.com

Engineering roles, interesting projects, and good conversations.

Rai Butera.

Senior engineer.Product builder.