FlashBoss

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.

Each DLC contains 1,000 new vocabulary words, with many more related words taught in the notes field.

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 six daily paces — from Luna's 8 cards a day to Aquila's 34. Choose by temperament and time commitment.

Some masters are bossy: they cap boss fights at three per 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.

The packs

Four 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.

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.

• Norman Roots — the French that arrived in 1066 and stayed.

• Greek Roots — the vocabulary of science and medicine. (in development)

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

All English content in FlashBoss is American English.