Koboshi is the language knowledge base for multilinguals and polyglots. Save the words you meet anywhere (ChatGPT, Duolingo, a screenshot) and spaced repetition brings them back until they stick, across every language you speak. Each word shows its meaning in all your languages side by side, since the language that makes it click changes from word to word. Save straight from ChatGPT or Claude with the Koboshi connector. There will always be a free plan.

Hi Product Hunt, I am a language fan and speak many languages. Before Koboshi, I used to study and save new words in chatGPT, most of them from Duolingo listening exercises that its word tracking never picked up. It worked for two or three months at a time. Then the chat filled up, the oldest words truncated, and it got messed up. Exporting to a spreadsheet was only partially done. Who knew about the truncation then? I needed something to record a word frictionlessly in the same motion as meeting it, and revisit later to practice it and learn as well, with a review that happens with a schedule. The second reason is personal. I also partly grew up in Pakistan and speak Urdu like a native, but my Urdu vocabulary sits around A2, maybe B1. Fluent mouth, thin dictionary. And when I look up a Spanish word, sometimes the English meaning makes it click, sometimes the Urdu, sometimes the Japanese. The language that unlocks a word is not predictable, so Koboshi shows the meaning across all your languages side by side. Your weaker languages get a small workout with every lookup. 一石二鳥 (Isseki Nicho), as we say in Japanese. What you can do today: • Look up a word and see its meaning in every language you know • Save words from anywhere, including straight from ChatGPT or Claude with the Koboshi connector. Hence you do not have to leave your chatGPT session while saving new words. • Review with spaced repetition (FSRS), so each word comes back right before you would forget it The name comes from 起き上がり小法師 (Okiagari Koboshi), the little Japanese doll that rights itself every time it falls, and from 取りこぼし (Torikoboshi), the things you let slip while trying to hold on. Words you looked up and lost. That is what Koboshi rescues. It is free to start, and there will always be a free plan. I would love to hear which languages you juggle, and what you would want Koboshi to do next.

Koboshi

Look up a word once, see it in every language you know

Look up a word once, see it in every language you know