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Sean Halberthal

Software Engineer

London, UK·+44 7930 271826·[email protected]·github.com/undont·linkedin.com/in/sean-halberthal

Profile

Backend and systems engineer working primarily in Go, with the full-stack range to take a product from database to UI. I work best owning a problem end to end, and care about the parts that don’t show: reliable data models, fast feedback loops, and tools that stay out of the way. Largely self-taught, I pick things up quickly and hold a high bar for software that’s actually pleasant to use.

Skills

Languages
GoTypeScriptJavaScriptC#LuaShellPythonC
Backend & Data
Node.jsPostgreSQLMySQLSQLiteMongoDBConvex
Frontend
ReactReact NativeExpoAstroTailwind CSSshadcn/uiVite
DevOps
DockerGCPGit & GitHubGitHub Actions (CI/CD)

Experience

Legal Practice Management for Barristers' Chambers
Self-employed (Contract)
C# · .NET · TypeScript · React · React Native
  • Core engineer on Dana, a multi-tenant SaaS platform for barristers' chambers covering case management, calendar synchronisation, clash detection, email threading and team collaboration across a backend API, web app and mobile app.
  • Built all three layers: a .NET backend (FastEndpoints, linq2db, PostgreSQL) in a vertical-slice architecture, a React web client and a React Native (Expo) app, with multi-tenant Microsoft 365 SSO on a Docker, Google Cloud and GitHub Actions CI/CD stack.
  • Owned developer tooling for the two-person team: a Makefile-driven git-worktree system that spins up fully isolated Dana stacks with auto-assigned ports, per-worktree Docker and Cloudflare tunnels, so both engineers could run multiple branches at once.
  • Led the team's AI-assisted development: set up the codebase's MCP integration and a shared agent config (CLAUDE.md, custom commands, skills, hooks and rules) so coding agents worked from consistent, repo-aware context.

Selected Projects

Tattoo Studio Management App
TypeScript · React · React Native

Cross-platform mobile and web app for tattoo studio and artist management, built solo with React, React Native and a Convex backend, styled with Tailwind and shadcn/ui. In active development.

seeql
Go

Keyboard-driven terminal SQL client for PostgreSQL, MySQL and SQLite, with constant-memory streaming for arbitrarily large result sets and context-aware autocomplete; pure Go with zero CGo, shipped as a single static binary.

supplyscan
Go · MCP

Supply-chain security scanner for JavaScript lockfiles, aggregating IOCs from DataDog, the GitHub Advisory Database and OSV.dev; runs as both a CLI and an MCP server.

differ.nvim
Lua · Go

Neovim plugin unifying local diffs, hunk staging and GitHub PR review, with a Go sidecar owning the GitHub API so reviews never block the editor.

Plus jiru, gh-bench, lazycron and more, with full write-ups at github.com/undont

Education

Boot.dev— Backend Development
  • Completed a comprehensive backend-engineering and computer-science curriculum, starting in Python and moving to Go, covering data structures, algorithms, databases and web servers.
  • Extended learning into lower-level systems (C, assembly and CPU architecture) and applied it through the projects above.
Music Technology (BTEC)— Kingston College

Additional Experience

  • Music producer & mix engineer (2018–present): built a freelance business to a recurring base of 30+ clients; now produce and engineer for a handful of artists alongside personal projects.
sean halberthalundont.dev