thedevbox
Privacy-first developer utilities that process data locally in the browser
A production-oriented collection of formatting, conversion, generation, and inspection tools designed around local execution, zero tracking, and a contributor-friendly extension system.
The 15-second brief
At a glance
- Outcome
- Replaces scattered single-purpose utility sites with one fast workspace that requires no account and keeps sensitive pasted data on the user's device by default.
- Delivery
- Shipped, 2026 · Personal
- Focus
- Frontend, Web
- Scope
- 8 core technologies
Ownership and evidence
What I built
The product decisions and engineering work that shaped the final result.
Delivered browser-first tools for structured-data formatting, URL inspection, timestamp and encoding conversion, identifier generation, and common debugging tasks.
Made local processing the default architecture so pasted payloads do not leave the browser unless a tool explicitly requires server-side execution.
Built the application on Next.js 16 and React 19 with strict TypeScript, automated tests, and a consistent component system.
Created a scaffold command that generates the component, shared logic, tests, registry entry, and mappings required for a new tool.
Enforced formatting, linting, tests, and type safety through Biome, Vitest, Lefthook, and pnpm-based workflows.
Product evidence
See it in action
Interface views and demonstrations from the working product.
27 tools organized by task, all running locally in the browser JSON formatter: format, minify, validate, and sort keys Color converter: hex, RGB, HSL, and CSS output for one swatch Curl converter: paste a curl command, get a fetch snippet back QR code generator with error correction, shape, and logo controls Diff viewer: line-level comparison with additions and removals highlighted Cron parser in the light theme, with a plain-English schedule breakdown