FlashBoss: Spaced Repetition and Boss Fights

Listen · Read · Repeat · Rate · Fight. A vocabulary course built around spaced repetition and boss fights. Foreign-language courses cover 3,000 of the most useful words, with naturally structured example sentences, English translations, and high-quality text-to-speech audio on every card. English packs teach with a definition and two example sentences per card.

FlashBoss is a serious study tool wearing RPG armor. If you want a study habit that fights back, welcome home.

Most packs teach 1,000 new vocabulary words (Advance is a tight 500), with many more related words taught in the notes field.

Your language, your interface

The whole interface runs in English, German, Japanese and Spanish — menus, lessons, boss fights, achievements, your master's own words. Ctrl+L switches instantly, on any screen. And where a pack offers it, you choose which language its translations and study notes display in: the full German course can be studied entirely through Japanese or Spanish.

How it works

Each card sets a target word in example sentences at a level you can follow. Words come in thematic clusters, and every cluster is gated by a boss fight: win it and the cluster graduates — your deck gets smaller as you go.

Try before you buy

Full word lists for every pack, every reference lesson, and a playable boss-fight demo are free to browse on the website. Link in the right sidebar.

Two ways to play

Work the structured course at your master's pace — or skip the syllabus and just fight. Every tier you clear becomes a low-stakes boss rush, for unlimited review.

Bank days off

Once the day's work is done, you can use a magic spell to bring tomorrow's workload forward — but be careful.

Boss fights

Each cluster ends in a duel: one step forward for a correct answer, two steps back for a mistake. As you practice, your flashcards are ranked by difficulty. The first two spaces deal you your easiest cards, and the last two, the hardest. This means you cannot defeat a cluster without facing your biggest challenges.

Choose your master

Six masters set the pace — from Luna's 8 cards a day to Aquila's 34. Choose by temperament and time commitment.

Some masters are bossy: they cap the day-banking spell at three uses a day to protect you from burnout. Others are advisory: they'll warn you it's a bad idea, then let you do what you want.

Pronounce anything

FlashBoss ships its own neural text-to-speech engine, and it is not locked to the cards. Press Ctrl+P on any screen to open the pronounce window: paste in any text — a letter, a homework sentence, a word that scares you — and hear it spoken properly, or save the audio to keep. Use it as a read-aloud tool for anything you are studying.

Out of the box you can pronounce English, German, Esperanto and Toki Pona. Italian and Spanish voices arrive with their courses, French is next, and British and Castilian Spanish voices are coming as separate voice packs. Voices follow the course languages, not the interface languages. Two honest notes: the pronounce window is mouse-driven, and the game itself does not support screen readers.

The packs

Five starter packs ship free:

• English Advance — the practical English of adult life: forms, letters, the fine print. 500 words.

• English Adept — sharper English for how you think, write, and speak. 1,000 words.

• German Core — the first 1,000 words of German, including a cultural integration section.

• Esperanto Core — one of the easiest languages to learn; 1,000 words goes far.

• Toki Pona — the complete course in the world's smallest language. Learn it in a week; think in it for life.

Further FlashBoss content:

• Latin Roots — build English vocabulary by recognizing the parts that make the whole. 1,000 words over 500 cards.

• German Roots — the Germanic backbone of everyday English. 1,000 words.

• Norman Roots — the French that arrived in 1066 and stayed. 1,000 words.

• Greek Roots — the vocabulary of science, medicine and philosophy. 1,000 words.

• Full 3,000-word courses in German, Spanish, Italian, and Esperanto. A1–C1 content arc.

• New releases every Thursday.

English text is American by default — and a per-hero setting switches every pack to British spelling. Where the two Englishes genuinely part ways, the cards teach your side of the Atlantic.

From the developer

I live in Germany, and I knew thousands of German words I could not use. Was it der Haufe or der Haufen? Die Haufen or die Häufen? I had known the word for years and never once trusted it. Working through my own course, gender, plural and spelling finally settled — word after word, for good. That is what FlashBoss is built to deliver: not just new words — certainty. It is built for brains like mine that bounce off textbooks: one card at a time, immediate feedback, visible progress, and a boss fight to make it count.