Jakub Dwojak

Aseity co-owner · Software developer

About

I’m Jakub, a software developer and co-owner of Aseity. I work with Java, Kotlin and Spring Boot, building backend systems, connecting services and helping teams ship projects. I’m also learning Japanese and building my own products, including Kaname and a collection of focused Japanese study apps. I enjoy working on both the engineering and product side of an idea. [Aseity](https://aseity.com.pl/en/) · [My apps](https://jd-japanese.pl/en/)

Links

Aseity

JD Japanese

Badges

Tastemaker

Gone streaking

Maker History

Kaname: Japanese GrammarJapanese grammar practice that adapts to your weak spots
Oct 2026

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Joined Product HuntOctober 8th, 2026

Forums

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1d ago

Kaname: Japanese Grammar - Japanese grammar practice that adapts to your weak spots

Practice Japanese grammar from JLPT N5 to N1 on iPhone. Kaname tracks recognition, fill-in-the-blank, contrast and sentence writing separately, then focuses reviews on your weakest skills. Compare similar patterns in context and study offline. All N5 content is free; unlock N4–N1 with one-time purchases. Optional AI sentence analysis is a separate subscription.