builds useful tools, fast
maarten brondijk · builder

I build useful tools. Fast.

A personal collection of things I've made, and a place to jot some thoughts. A few run daily inside companies, some are just for fun. Here's the what and the how.

Latest post Coding from my phone with pocketdev and Claude Code 2026-07-04 →
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WK 2026 Prediction Pool overview: header, full navigation, and a live match WK 2026 Prediction Pool

WK 2026 Prediction Pool live

An office World Cup pool I built instead of paying Scorito €200 per group: idea to live in about an hour, now used by 30 colleagues. Live scores, match minutes and goalscorers auto-import from a public API, and the leaderboard reshuffles in real time during matches. Weekly bonus rounds, closest-guess metagames, fully customizable scoring. Free, no ads.

How: React + Vite on Netlify Functions & Blobs, fully serverless, no database. Live match data pulled from a public football API.
30 players 104 matches live scores via API idea → live in 1h €200 saved
Read the case study →
Tools that run daily
Stock Dashboard JJ Stock Dashboard · JJ

Stock Dashboard · JJ daily

An operational stock command-centre for a nutrition brand that tracks every SKU across EU & US, flags below-safety and critical stock, and projects out-of-stock dates from the live subscription queue.

How: Python pipeline off Google Sheets masters → a fast static dashboard. Automatic safety-stock and reorder logic, EU/US toggle.
51 SKUs EU + US €453K stock value
internal tool · screenshots only
Stock Dashboard ME Stock Dashboard 2

Stock Dashboard 2 daily

The same stock-intelligence engine adapted for a second company's catalogue and supply chain, used daily by its ops team. One build, two businesses.

How: Reused the JJ engine, re-skinned and re-wired to a different data source. Proof the tooling generalises beyond one company.
2nd company reused engine daily use
internal tool · screenshots only
Master Insights dashboard Master Insights

Master Insights daily

A revenue command-centre: month-to-date vs target pacing, channel split (Shopify vs Recharge, INT vs US), subscription share, and a daily revenue-vs-target curve against last year.

How: Aggregates daily sales across channels into one EUR view (incl. USD conversion) with live pacing against monthly targets.
MTD pacing multi-channel EUR + USD
internal tool · screenshots only
Global Order Visualizer Order Visualizer

Order Visualizer 2025

A 3D globe that draws every order shipped from Amsterdam to the world: glowing arcs from the warehouse to each destination city. Privacy-safe: only city and postal code, no personal data.

How: Mapbox GL globe with great-circle arcs generated from anonymised order geodata.
Mapbox globe privacy-safe 2025 orders
internal tool · screenshots only
More projects
Flightvisualizer global flight map Flightvisualizer

Flightvisualizer.com

Real-time flight tracking visualization with global coverage.

pythonmaps
View project →
Taskflow-done.com Taskflow

Taskflow-done.com

Minimalist task management with automation built in.

webautomation
View project →
Fun Side Quests Side Quests

Fun Side Quests

A collection of smaller, experimental projects and coding adventures.

experiments
View side quests →
Country Tracker Country Tracker

Country Tracker

Map of everywhere I've been: a small personal travel log.

mapspersonal
side project
From the blog