When Mozilla shut down Pocket in July 2025, I lost my favorite tool. Worse, none of the English alternatives (Instapaper, Readwise, Matter, Raindrop) had Japanese UI, and their article extraction was mediocre on Japanese pages.

So I built one. It's called Readbox — Japanese-first, English-too, read-later as a PWA. Here's what I learned shipping it.

The stack

Next.js 15 App Router + TypeScript strict (no any)

Supabase (Postgres + Auth + RLS)