Language Learning App Boilerplate for SwiftUI

Streaks: the retention loop that keeps learners coming back

In language learning, the daily streak is not a vanity number — it is the product. It is the single mechanic that converts a curious downloader into a habitual user, and it is what gives your push notifications a reason to exist. The Swift Kit gives you the durable, per-user state this needs: Supabase auth (email + Sign in with Apple) tied to a Postgres database where you store the last-active date, current streak count, and XP per user. Because the data lives server-side rather than in local UserDefaults, a learner's streak survives a reinstall or a switch to a new phone — the kind of detail that quietly destroys trust when you get it wrong. Push notifications and TelemetryDeck analytics ship in the same kit, so you can fire a 'don't break your 12-day streak' reminder and actually measure whether it brought people back.

• Per-user streak, XP, and last-active state in Supabase Postgres, not fragile local storage
• Push notifications wired for streak-reminder and lesson-due nudges
• TelemetryDeck analytics to measure D1/D7 retention and notification lift
• Sign in with Apple so progress follows the learner across devices

Subscriptions: how an Edtech MVP actually makes money

Free lessons get installs; subscriptions pay for the content team. The Swift Kit ships RevenueCat as the payments layer, which means a configurable paywall, free-trial and intro-offer handling, and multi-tier entitlements out of the box — so you can run a free tier (a few lessons a day), a 'Plus' tier (unlimited lessons), and a 'Tutor' tier (unlimited AI conversation) without writing StoreKit receipt-validation code by hand. The paywall is one of six feature-flagged modules, so you can A/B a hard paywall against a freemium gate by flipping a boolean rather than re-architecting. Pair this with the streak loop and you have the classic language-app funnel: hook on the habit, gate the depth behind a subscription.

AI tutoring without leaking your API keys

Conversational practice is the feature that separates a flashcard app from a real tutor, and it is where most indie builders get burned — either by shipping their OpenAI key inside the app binary, or by having a single user's runaway prompt loop drain their account overnight. The Swift Kit proxies every AI call through Supabase Edge Functions, so your keys stay server-side and you get per-user rate limiting for free. You get OpenAI streaming chat (a back-and-forth tutor that corrects a learner's sentence), Vision (point the camera at a menu, get a translation drill), and Anthropic Claude as a second model. For low-stakes, high-volume tasks like generating a quick example sentence, Apple Foundation Models run free and on-device — which keeps your per-conversation cost near zero on newer phones.

• OpenAI keys proxied via Supabase Edge Functions — never shipped in the app
• Per-user rate limiting so one learner can't drain your AI budget
• Streaming chat for conversational correction; Vision for camera-based drills
• Free on-device Apple Foundation Models for cheap example-sentence generation

What you still have to build — and when this isn't the right fit

Be clear-eyed: The Swift Kit is the infrastructure under a language app, not the curriculum inside it. It does not ship a spaced-repetition (SRS) scheduling algorithm, a lesson-authoring CMS, audio pronunciation scoring, or any actual language content — those are your product, and they should be. If your entire idea is a thin wrapper around ChatGPT with no streaks or subscription logic, a simpler starting point may serve you better. And if you are committed to Android-first or a cross-platform launch, a native SwiftUI kit is the wrong tool — look at a Flutter or React Native path instead. The Swift Kit earns its keep when you are building a native iOS Edtech MVP and want the retention-and-revenue scaffolding done so you can focus on teaching.

The Swift Kit vs. building your language app from scratch

Frequently Asked Questions