Koine is a Koine Greek vocabulary and Bible (NT) study app for anyone looking to deepen their knowledge of the language that backs the Word of God. Moreover, this app is also meant to enlighten the learner around the nature of the available Greek texts, the differences between them, and how they have shaped the translated Bibles we have today.

Build custom vocabulary decks and study with FSRS — a modern spaced repetition algorithm that adapts to your actual retention rate, scheduling cards at the optimal moment for long-term memory. It outperforms older Leitner-style systems by modeling forgetting curves per card.

Add any word to a deck directly from the reader — no switching between apps. Search all 5,000+ Greek NT words by lemma, transliteration, or English definition. Filter by part of speech, frequency, and more. See every inflected form, its parsing, and all NT verses where it occurs.

Start your deck with structured vocabulary paths instead of building from scratch:
• Frequency tiers — the 100, 200, 300, or 500 most common NT words
• Theme, grammar, and word-familial presets
• Mounce Basics of Biblical Greek chapter-by-chapter vocabulary
• David Alan Black's Learn to Read New Testament Greek
• Passage-based decks — generate a deck from any NT book or chapter to study before reading it (Premium)

Read the Greek New Testament and tap any word to instantly see:
• Lemma, transliteration, Strong's
• Full parsing (tense, voice, mood, case, number, gender)
• Abbott-Smith lexicon definition
• Thayer's Greek Lexicon entry (Premium)
• NT occurrence count and frequency
• All inflected forms found in the NT

Comes with four bible texts for reference, all available offline:
• Textus Receptus (TR) — Stephanus/Elzevir/Scrivener collation
• SBL Greek New Testament (SBLGNT)
• King James Version (KJV)
• Lexham English Bible (LEB)

Switch between editions at any time. Greek editions support full tap-to-parse; English editions are included for side-by-side reference.

The core app is completely free — no subscription, no ads. A one-time Premium unlock ($8.99) adds:
• Unlimited decks (free tier: up to 3)
• Thayer's Greek Lexicon
• Compare-manuscripts tool
• Passage-based deck generation
• Frequency-based auto-decks
• Study statistics dashboard

Sources (more detailed in the app):
• Lexicon and morphology data from STEPBible.org (Tyndale House Cambridge, CC BY 4.0).
• Bible texts from eBible.org.
• Definitions from Abbott-Smith
and Thayer's Greek lexicons.