React Native + Expo source · iOS and Android

A vocabulary app that explains its own schedule.

Vocabryn is runnable app source for learning useful phrases. Learners choose or import a collection, study in short sessions, and every grade shows exactly when the card comes back — and why. Everything runs on the device.

See the three journeys Setup & build guide

Provisional review. Every screen on this page is a capture of the real app running on iOS Simulator and Android Emulator — not a mockup. Native source is delivered as a ZIP; nothing here is an app-store listing. A physical Android phone and a physical iPhone passed the journeys, accessibility and performance checks.

Vocabryn Today screen on iOS: due cards, the week-ahead forecast and studied collections — iOS Simulator · Today

Vocabryn study card on Android with Again, Hard, Good and Easy buttons showing their intervals — Android Emulator · Study card

Expo SDK 57React Native 0.86 · TypeScript
13 screens4 tabs · 8 stack · recovery
48 phrases4 original collections + import
119 testsJest unit and journey tests
7 flowsMaestro on simulator and emulator
OfflineNo account, server or tracking

What a learner can do

Three journeys, working end to end

Choose or import a collection

Four original collections — workplace phrases, connectors, precise verbs, travel — switched on or off in the Library.
Import CSV, tab-separated text or JSON from a file or by pasting; every row is validated, problems are listed by row, and a preview comes before saving.
Files are read on the device and never uploaded.

Welcome screen with collection choices — iOS · First run

Library with collection cards, progress bars and study switches — iOS · Library

Import screen showing four rows ready to import — iOS · Import preview

Study a session

New phrases are introduced as dictionary entries; reviews alternate between recall and a gap-fill in the example sentence.
Again, Hard, Good and Easy each show the interval they will give before you tap.
Every answer is saved at once: leave mid-session, background the app or close it, and the session resumes where it stopped.

A new phrase introduced as a dictionary entry — iOS · First look

Recall card with meaning revealed and grade buttons — iOS · Recall and grade

Gap-fill prompt with four phrase options — Android · Gap-fill

Review what's due and why

Today shows what is due now, later today and over the next seven days.
History groups answers by day with a 30-day remembered rate.
Each phrase page states its stage, ease and next date, explains that date in one sentence, and lists its review timeline.

History screen with remembered rate and answers grouped by day — iOS · History

Phrase page with schedule facts and the reason for its next date — iOS · Why this date

History screen on Android — Android · History

Deterministic, documented, testable

The schedule, in plain words

A variant of SM-2 with learning steps and four grades. No randomness: the same answers always give the same dates. Every constant lives in one config file, which the app's own "How scheduling works" page reads.

Answer	New or learning phrase	Phrase in review (interval × ease)
Again	Back in 1 minute	Forgotten: ease −0.20, relearn in 10 minutes, keep 20% of the interval
Hard	Repeat the current step	Interval × 1.2, ease −0.15
Good	Next step (1 → 10 minutes), then 1 day	Interval × ease (starts at 2.50)
Easy	Straight to 4 days	Interval × ease × 1.3, ease +0.15

Study days start at 04:00 · ease never drops below 1.30 · intervals stop at 365 days · six lapses mark a phrase "tricky"

Designed for both themes and every text size

Dark mode, large text, screen readers

The dark palette is designed separately, not inverted, and every text colour is tested for 4.5:1 contrast. At the largest text sizes the grade buttons regroup into a 2×2 grid; every control has a spoken label, and Reduce Motion removes the card transitions.

Today screen in the dark theme — iOS · Dark

Phrase page in the dark theme on Android — Android · Dark

Study card at the largest accessibility text size — iOS · Largest text size

Today screen at 200% font scale on Android — Android · 200% font

Honest boundaries

What's included, what needs your backend

Included, works offline

Collections, CSV/JSON import, sessions, scheduling and history
Saved progress, interrupted-session restore, data-recovery screen
Backup export and restore as a JSON file
Daily reminder as a local notification
"Hear it" with the device's own text-to-speech voice
Light and dark themes, rebrand tooling, Jest and Maestro tests

Needs your backend

Accounts and sign-in (adapter interface included)
Cloud sync between devices (adapter interface included)
Server push notifications

Not included

Purchases or subscriptions
AI tutor or generated lessons
Speech recognition or pronunciation grading
Licensed textbook content, analytics or tracking

What was actually run

Verification for this review

Check	Environment	Result
Clean package checks	Extracted buyer ZIP · Node 24.21 · Expo Doctor 21/21	passed
Typecheck, lint and Jest	Extracted buyer ZIP · 6 suites / 119 tests	passed
iOS release build	Xcode 27 · iOS 16.4 minimum · arm64 Simulator	passed
iOS journeys and accessibility text	iPhone 17 Pro Simulator · iOS 26.5 · 6 runs	passed
Android release build	JDK 17 · compile/target SDK 36 · release APK	passed
Android journeys, 200% text and reduced motion	Pixel 8 Emulator · Android 16 / API 36 · 8 runs	passed
Rebrand trial	Phrasewell · new IDs, palette, type and content · both release builds	passed
Physical Android phone: journeys and Back	Samsung Galaxy A24 (SM-A245F) · Android 16 · Release APK	passed
Release performance on Android hardware	Galaxy A24 · cold launch 1.12 s · p95 frame 24 ms · thermal 0	passed
Signed iPhone Release build	Xcode 27 · iphoneos · free development team (no push entitlement)	passed
Physical iPhone: journeys, restart restore and deep links	iPhone 14 Plus · iOS 26.6.2 · signed Release build · 3 journeys	passed
Physical iPhone accessibility audit	Xcode accessibility audit · 8 screens · 0 issues	passed
Release performance on iPhone hardware	iPhone 14 Plus · cold launch 0.17 s · 0 hitches · scroll 58.6 fps	passed

In the ZIP

A source package you can make your own

One brand file sets the name, bundle IDs, deep-link scheme and icon colours; a script regenerates every icon and splash image. Colours, fonts, copy, collections and scheduling rules each live in one place.

vocabryn/
├── app/                 Expo app (the product)
│   ├── brand.config.json    name, IDs, scheme, colours
│   ├── src/app/             screens (Expo Router)
│   ├── src/domain/          scheduler, queue, import, stats
│   ├── src/config/          theme, schedule rules, defaults
│   ├── src/content/         collections
│   ├── __tests__/           Jest unit + journey tests
│   └── e2e/                 Maestro flows
├── docs/                setup, native builds, rebrand, integrations
└── START-HERE.md · BUYER-README.md · LICENSE.txt

Read the setup & build guide