Decks and Flashcards

NIP-DF: Decks and Flashcards#

Summary#

Defines a standard format for representing decks of flashcards and flashcards themselves as Nostr events, including how to link flashcards to their parent decks.

Tags#

deck, flashcard, learning, education

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Motivation#

There is currently no standard way in Nostr to create structured learning materials like decks of flashcards. This NIP enables:

• Users to create decks and share them.
• Flashcards to be attached to decks.
• Flashcards and decks to be synchronized, versioned, and distributed across clients.

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Event Kinds#

Kind	Name	Description
30500	deck	Defines a deck of flashcards
30501	flashcard	Defines a flashcard attached to a deck

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Deck Event (kind: 30500)#

A deck event represents a named collection of flashcards.

{
  "kind": 30500,
  "tags": [
    ["d", "<deck-id>"],
    ["name", "Basic Math"],
    ["description", "A deck of flashcards covering basic arithmetic."],
    ["subject", "Mathematics"],
    ["version", "1"]
  ],
  "content": ""
}

Required Tags#

• ["d", <deck-id>]: A unique ID for the deck (deterministically derived or randomly generated).
• ["name", <deck-name>]: The display name of the deck.

Optional Tags#

• ["description", <text>]: A human-readable description.
• ["subject", <topic>]: Topic or category (e.g., history, math, science).
• ["version", <version>]: Version number for content updates.

Flashcard Event (kind: 30501)#

A flashcard event represents a single question/answer pair.

{
  "kind": 30501,
  "tags": [
    ["d", "<deck-id>"],
    ["order", "3"],
    ["version", "1"]
  ],
  "content": "{\"front\": \"What is 2 + 2?\", \"back\": \"4\"}"
}

Required Tags#

• ["d", <deck-id>]: The deck ID this flashcard belongs to.

Optional Tags#

• ["order", <index>]: Index within the deck (integer or string).
• ["version", <version>]: Version of the flashcard.

Content Format#

Must be a JSON object:

{
  "front": "Question or prompt",
  "back": "Answer or explanation"
}

Optionally, clients may support extra fields such as "hint" or "media".

Deterministic Deck ID#

Clients may derive the <deck-id> using a sha256(pubkey + created_at + name), or generate it randomly (e.g., uuidv4()), ensuring uniqueness.

Extensions (Future NIPs)#

• Progress tracking: Add kind: 30502 to log study sessions or flashcard scores.
• Collaboration: Multi-author decks.
• Flashcard types: Support multiple choice, true/false, cloze deletion.
• Media support: Embed or link images/audio.

Backward/Forward Compatibility#

Clients not recognizing kind: 30500 or 30501 will safely ignore them.

Use Cases#

• Personal study apps
• Public learning repositories
• Flashcard marketplaces
• Collaborative classroom tools

Example Flow#

1. Alice creates a deck Basic Spanish (kind: 30500).
2. Alice creates 10 flashcards (kind: 30501) tagged with the deck ID.
3. Bob subscribes to Alice’s pubkey and loads the deck and cards.
4. Bob studies and optionally tracks his progress with kind: 30502.