extrovert.cafe — IoT + web · self-service coffee points

Self-service coffee points with a Raspberry Pi kiosk, fiscal integration and a game where every cup grows your coffee buddy.

Role: Founder · sole engineer: kiosk software, backend, web apps, infrastructure, brand

Client: Own business

Team: Solo

Period: 2026–present

An unattended coffee point needs more than a vending machine. The menu screen must never freeze on modest hardware, every sale needs a fiscal receipt under Ukrainian rules, the owner has to know at once when a point goes silent, and guests need a reason to come back rather than pick the next machine down the street. extrovert.cafe is my own venture, so the whole system was built from scratch.

On the point, a native menu renderer written in C with Cairo and GLES2 draws straight to the display of a Raspberry Pi without X, while a supervisor and self-updater pull releases from Cloudflare R2. In the cloud, Node.js services in Docker handle the REST API, WebSocket events, Checkbox fiscal webhooks with receipt reconciliation, scheduled jobs and a Telegram overseer bot that reports silent points and daily totals. The guest app and the admin are React SPAs on Cloudflare Workers, backed by PostgreSQL and Redis.

Kiosk: C + Cairo + GLES2 menu renderer on Raspberry Pi, 4K layout, OTA updates

Fiscal: Checkbox PRRO webhooks, receipt polling and price reconciliation

Guest app: Google sign-in, coins and beans, a buddy that grows with every cup

Shop and wardrobe for merch and outfits, Nova Poshta checkout, drink surveys

Admin: point telemetry, silent-point alerts, sales statistics, Telegram reports

In operation since August 2026; 634 commits in two months, documented and provisioned with Terraform

C / Cairo / GLES2, Raspberry Pi, Node.js, React, PostgreSQL, Redis, Docker, Cloudflare Workers + R2, Checkbox API