Hi, I'm Sébastien 👋

Full Stack Developer — Elixir/Phoenix · JavaScript · PostgreSQL · SaaS . API Integration Developer

I spent 3 years on the other side of the API — debugging integrations, resolving 3000+ support tickets at Sellsy. That taught me exactly where systems break under real usage. Now I build them: contributing to the Elixir core language and the Ash ecosystem, and shipping a multi-tenant SaaS platform from scratch.

🟢 Open to work — Full CV

• Backend: Elixir, Phoenix, Phoenix LiveView, Ash Framework
• Data: PostgreSQL, multi-tenancy (Triplex), full-text search (tsvector/ts_rank)
• Infra: Fly.io, Docker
• Other: Rust (Rustler NIFs), API integration, OAuth/Webhooks
• Javascript: Angular, Vue.js, Vanilla JS, Node, Express, Nest

Merged contributions to core Elixir ecosystem projects:

• elixir — merged by José Valim
• ash (Ash Framework) — merged by Zach Daniel
• postgrex — clarified Duration/interval decoding in docs
• cfonb (Ruby, Pennylane) — fixed a silent line-dropping bug in the bank statement parser

Phoenix / LiveView

• rover — interactive maps for Phoenix LiveView, powered by OpenLayers. Assign a list of markers, get a live map.
• coelho — structured rich text for Phoenix. Inspired by Action Text, except it does not store HTML.

Search

• search_ash — multilingual full-text search for Ash, using pre-stemmed tsvectors (~30 languages)
• search_core — the same building blocks without Ash: stemming pipeline and Postgres tsvector/tsquery helpers for plain Elixir/Ecto
• stemmers — Rust/Rustler NIF powering the stemming in both

Ash

• green_ash — keyboard-driven, AS/400-style LiveView console generated from Ash resource introspection. mix igniter.install green_ash

Domain-specific

• cfonb — parser and emitter for CFONB bank files, the French banking standard (120-char account statements)
• facturx — pure-Elixir toolkit for Factur-X/ZUGFeRD, the Franco-German EN 16931 e-invoicing standard. Generate, extract, parse, validate — veraPDF-valid, XSD/Schematron-valid.
• green_cal — sun and moon ephemerides for agricultural calendars (Meeus' algorithms, pure Elixir, zero dependencies)

• pdf-inspect-elixir-poc — drag & drop PDF analysis in LiveView, calling a Rust CLI over an OS Port rather than a NIF: a crash in the external tool cannot take down the BEAM
• acmescript — Elixir-flavoured JavaScript helpers for LiveView hooks and .heex templates
• SortableBoilerPlate · right-click-elixir — minimal, readable examples of LiveView JS hooks

A French-language "awesome Elixir": curated libraries, a glossary FR ↔ EN, executable Livebooks, and a guided learning path — because the French-speaking Elixir community has almost nothing of its own.

It also hosts a blog of original articles in French: immutability and structural sharing, LiveView streams, Ecto.Multi, concurrent tests with a database, reading a stacktrace, :queue and zippers, debugging with dbg and pry. Every measurement is reproduced before it is published, and every article can be corrected by pull request.

Music software and tooling, mostly for my own instruments:

• Sysex77 — MIDI editor for the Yamaha SY77/TG77/SY99 FM synths, built with JUCE in C++
• Juce-Simples-Exemples — small, self-contained JUCE examples
• maxx — a visual workshop that builds GPUI views and writes them out as real Rust source
• factur-x-ts — TypeScript-native Factur-X EN 16931 generator and parser, strictly typed, zero any
• sysop-tui — Rust TUI for links, encrypted secrets, notes and reminders

Multi-tenant SaaS for gardeners — from plots to customers. CTIFL labels, stock & point-of-sale transfers, invoicing, customer portal, and more.

Built solo with Elixir, Phoenix LiveView, Ash Framework, PostgreSQL, deployed on Fly.io.

Sellsy — API Technical Support (2023–present) / Software Developer (2022–2023)

• 3000+ support tickets/year on API integrations, 98% satisfaction
• Reverse-engineered and documented undocumented API models
• Reduced recurring support issues 20% through improved documentation

275+ hours of technical training (Dyma Academy) · 8 certifications (Git, Python, Linux, Docker) · Mentored 80+ developers · StackOverflow contributor

• 🔗 GitHub: @nseaSeb
• ✍️ Blog (FR): Elixir & Phoenix
• 📧 nseaprotector@gmail.com
• 🌍 Trizay, Nouvelle-Aquitaine, France 🇫🇷