The gold-standard spaced-repetition flashcard app with community decks for every language.
AppsTools Free BeginnerIntermediateAdvanced
vocabulary
Details
Free on desktop, Android and web; the iOS app is a one-off paid purchase that funds the project. The interface is dated and the options are overwhelming at first, but nothing beats it for retaining vocabulary over years. Most effective when you stop grinding premade decks and start mining sentences from things you actually read or watch.
Free public-domain US government language courses with textbooks and audio.
CoursesBooks Free BeginnerIntermediateAdvanced A1–C1
grammarlisteningspeakingreading
Details
Foreign Service Institute, Peace Corps and DLI materials — full textbooks plus hundreds of hours of audio — are public domain and hosted here for free across dozens of languages. The depth is extraordinary and the FSI Basic courses take diplomats to professional working proficiency, which no consumer app attempts. The recordings are from the 1960s–80s, the drills are relentless, and some vocabulary is dated (Cold War era), so they suit disciplined self-studiers, not casual learners.
Teaches grammar and vocabulary entirely through screenshots from Japanese video games.
YouTube Free BeginnerIntermediate A1–B2
grammarvocabularyreading
Details
Every grammar point and word is illustrated with real in-game text from titles you probably recognise, which makes it stick and shows you the language as it is actually written. Structured roughly along JLPT levels so you can follow it as a course. Free on YouTube. Obviously best if you play games in Japanese; the examples skew toward RPG and fantasy register.
Encyclopedic free grammar reference covering points no textbook goes near.
Websites Free IntermediateAdvanced B1–C2
grammarreading
Details
Hundreds of lessons that go far deeper than any commercial course, including Classical Japanese, dialects and rare constructions, all free. This is where you go when you hit a grammar point nothing else explains properly. Absolutely not a beginner's first course — the writing is academic and the sheer volume is discouraging if you start at lesson one.
Very thorough native-speaker grammar lessons, plus how people actually talk.
YouTube Free BeginnerIntermediate A1–B2
grammarlisteningpronunciation
Details
Misa goes into far more detail than a textbook on individual grammar points and is unusually good at explaining the casual, contracted and slangy forms that textbooks skip entirely. Videos are long — often 30 to 60 minutes on a single point — which is a feature if you want depth and a problem if you want a quick answer. All free on YouTube.
The default English–Japanese dictionary: search by kanji, radical, reading or meaning.
DictionariesWebsites Free BeginnerIntermediateAdvanced
readingvocabulary
Details
Built on the free JMdict/KANJIDIC data, it handles wildcard searches, deconjugates verbs, draws kanji by radical or handwriting, and tags words by JLPT level and commonness. Free with no account required. The example sentences come from Tatoeba and vary in quality, and for nuance between near-synonyms a monolingual dictionary will serve you better once you can read one.