Nibomo

AI-powered open-source flashcards app for iOS, Android, and web.

Nibomo screenshots

Nibomo (formerly Flashcards Open Source App) is an open-source AI-powered flashcards app built for serious daily study on iOS, Android, and the web. Use it to prepare for exams, learn vocabulary, memorize technical terms and facts, improve your material with AI, and review with spaced repetition. The project also includes an external agent API for terminal and AI-agent workflows.

Available on

iOS
Android
Web
MCP server: https://mcp.nibomo.com/mcp
Agent API: https://api.flashcards-open-source-app.com/v1/

Card scheduling

Card scheduling uses FSRS-based spaced repetition. Detailed scheduling rules live in docs/fsrs-scheduling-logic.md.

MCP connector

The hosted MCP server is available at https://mcp.nibomo.com/mcp and publishes to MCP registries under com.nibomo/flashcards. It exposes eight tools, most of them workspace-scoped: list_workspaces, sql_query, sql_execute, get_guide, next_review_card, reveal_answer, submit_review, and the account-scoped get_usage_limits.

The dedicated review tools support one-question-at-a-time conversations and idempotent FSRS scheduling. See conversational reviews for the contract shared by MCP, the in-app chat, and the Agent API, and for voice-session examples. ChatGPT Voice currently does not invoke apps/MCP; these tools do not remove that external limitation.

Interactive clients authenticate with OAuth 2.1 authorization code + PKCE and Dynamic Client Registration. Headless clients can use an fca_ Bearer token.

The former address https://mcp.flashcards-open-source-app.com/mcp still serves the same server, so existing client configurations keep working. A client moved to https://mcp.nibomo.com/mcp authorizes once more; backend and web deployment owns why.

Docs

License

This project is licensed under the MIT License - see the LICENSE file for details.

Author

Kirill Markin