Alexis Vargas

Chess learning and tournament platform that I designed and built as the only engineer: about 2,000 commits across 12 repositories since June 2025.

• Django 5.2 / DRF API with about 330 API operations and about 1,050 tests, running on Railway as four services from one Docker image (web, Celery worker, Celery beat, WebSockets). CI runs the tests against PostgreSQL and Redis.
• Real-time live lessons and games on Django Channels: room state in Redis, every event stored in a PostgreSQL event log, and state rebuilt from the log after a restart.
• Flutter app for iOS and Android, live on the App Store and Google Play, in English and Spanish, with push notifications and on-device Stockfish analysis.
• Vue 3 + TypeScript web app with Stockfish compiled to WebAssembly in a Web Worker and an OpenAPI-generated API client.
• Offline-first desktop app for tournament arbiters that syncs with the API through idempotency keys, so a retried request never applies twice.
• Own Glicko-2 rating implementation for puzzles and players, checked against Glickman's published worked example.

Pure-Python library for chess tournament pairings, published on PyPI (12 releases).

• Implements the FIDE Dutch Swiss system with Baku acceleration, FIDE Berger round-robin and a casual Swiss mode, plus TRF16 import and export.
• Pairs each round with maximum-weight matching (Edmonds' blossom algorithm); the edge weights encode the FIDE criteria.
• 0 discrepancies against bbpPairings, FIDE's reference engine, across 10,000 simulated tournaments. Not FIDE-endorsed.
• 252 tests, run in CI on Linux and macOS with Python 3.10 to 3.13.

Offline-first desktop app for chess arbiters: Swiss and round-robin pairings, TRF16 import/export, tiebreaks, PDF sheets and one-click sync to the cloud.

• Rust backend with SQLite, React 19 + TypeScript front end, English and Spanish.
• Ships the Python pairing engine inside the app as a self-contained sidecar.
• GitHub Actions builds signed installers for macOS (notarized), Windows and Linux; CI runs type checks, tests, cargo fmt and clippy.

• Teach group classes, private lessons and training squads for juniors and adults
• Plan lessons and progressions, and prepare students for rated tournaments
• This work shaped the tournament and coaching tools I built in Caissify

• Developed and maintained features in a Ruby on Rails SaaS platform
• Wrote complex PostgreSQL queries and reports, and connected them to Vue.js front ends
• Implemented Elasticsearch-backed search
• Worked in sprints with Jira, pull-request code review and CI in an Agile team

• Designed and built REST APIs in Laravel for several client projects, used by web and mobile apps
• Modelled relational schemas and wrote efficient queries
• Agreed API contracts with front-end and mobile developers

• Maintained and extended e-commerce products built on Laravel, WordPress/WooCommerce, Vue.js and Angular
• Integrated Elasticsearch for product search
• Delivered client features in a small development team