🛠️ Data Handling & Sync

Lurnly is (currently) a fully client-side application - there is no server, no account, and no cloud. All of your data lives in your browser.

This is subject to be changed. With accounts & managment being planned in future updates.

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How Data Flows

Every action you take - creating a deck, studying cards, tracking progress - is saved to and read from your browser's Local Storage. Nothing is ever sent to a server.

Your Action
study, create, import

localStorage
browser storage

Dashboard
reads & displays

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What Gets Stored

Lurnly uses two separate keys in Local Storage:

lurnly_decksArray of deck objects

Stores every deck you own — name, icon, cards, progress percentage, creation date, and last studied date.

lurnly_study_logDaily card counts

A date-keyed record of how many cards you studied each day. This is what powers the Day Streak and Studied Today stats.

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Deck Data Structure

Each deck is stored as a JSON object. Here's what a v1.3 deck looks like:

{
  "id": "deck_1714000000000_0",
  "name": "Spanish Basics",
  "icon": "🇪🇸",
  "description": "Common Spanish vocabulary",
  "author": "You",
  "progress": 64,
  "created": "2026-03-01T10:00:00.000Z",
  "lastStudied": "2026-04-17T18:30:00.000Z",
  "shuffle": false,
  "timer": null,
  "cards": [
    { "front": "Hola", "back": "Hello" },
    { "front": "Gracias", "back": "Thank you" }
  ]
}

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Format Compatibility

Lurnly reads both the current format and older exports, so decks from previous versions import without issues.

Field

Old Format

v1.3

Cards array

flashcards

cards

Deck name

title

name

Icon

emoji

icon

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Auto-ID

When importing a deck that has no id field, Lurnly automatically generates one using the current timestamp:

deck_1714000000000_0

This ensures every deck can be uniquely identified for studying, editing, and deletion — even if the original export pre-dates the ID system.

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⚠️ Important Limitations

🌐

Browser-bound: Your data only exists in the browser where you use Lurnly. A different browser or device will start with an empty library.

🗑️

Clearing site data wipes everything. Clearing your browser's cookies/storage for the site permanently deletes all decks and progress. Export your decks regularly as a backup.

☁️

No cloud sync. There is no account system. To move decks between devices, use the Export → Import workflow.