Library Universe
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Library
Universe
A digital platform for serious German learners
built around real journalism, vocabulary, and deliberate practice.
Product PitchPortfolio2025

The Concept

Not a language app.
A learning environment.

Clarity over noise

One focused interface. No streaks, no badges, no distractions.

Consistency over hacks

Daily reading practice. Deliberate vocabulary acquisition.

Depth without intimidation

Real German texts, adapted for three proficiency levels.

"Learn German by writing, thinking, and returning daily."

The Problem

Existing tools are either
too childish or too academic.

"Great job! You earned a gem!"
A vocabulary deck you built yourself, reviewed at your own pace.
500-page grammar textbook with no context.
A Süddeutsche Zeitung article — adapted for your level, with audio and questions.
Apps designed for a 10-year-old's attention span.
A serious learning interface for people who want to think clearly in German.

Feature 01

German news articles
at three reading levels.

Every article is available in Easy, Medium, and Advanced German — editorially adapted, not machine-translated. Learners switch levels as they progress.

  • Audio playback per language level
  • Comprehension questions with feedback
  • Commentary cards for politics articles
  • Critical-thinking prompts + community comments
  • Filters: category, region, political leaning, agency
  • Author profiles with journalistic background

Level Switcher

EasyMediumAdvanced

Categories

Politics & EconomicsCultureScienceSociety

Political Framing

Political articles show leaning and agency level — helping learners read with critical awareness.

Feature 02

An AI-powered editorial layer
for learner engagement.

Comment Proofreading

Learners write German comments in response to articles. Before posting, an AI proofreads their German — checking grammar, relevance, and tone. The corrected version is shown alongside feedback.

Automatic Moderation

Every comment is scored in real time: trolling likelihood, AI-generated text probability, and on-topic relevance. Comments requiring review are flagged automatically before appearing publicly.

Powered by OpenAI GPT · Sanity CMS · Structured schema validation

Feature 03 · Research

Political leanings
of AI models.

A research tool that surveys major AI language models — GPT-4o, Claude, Gemini — on a standardized set of political questions. Results are stored, visualized, and available for comparison.

Standardized Questions

Political compass–style questions across economy, society, and governance — translated into multiple languages.

Model Comparison

Side-by-side views of how different AI models respond to identical political prompts.

Editorial Relevance

Directly relevant to newsrooms adopting AI tools — surfaces hidden biases before deployment.

Feature 04

Flashcard decks
designed to be kept.

Vocabulary decks organized by CEFR level (A1–C1), theme, and grammar category. Cards feel like collectibles — not exam prep.

Study Modes

  • Swipe Study — fast recognition practice
  • Cloze — fill-in-the-blank sentence context
  • Noun Gender — der / die / das training
  • Spaced repetition built into the review flow
3
Study modes
A1–C1
CEFR coverage

Access Tiers

Free decksPremium decks

Commerce layer for premium deck access built into the platform.

Features 05 & 06

Crosswords. Research.
A complete learning system.

German Crosswords

Editorially crafted vocabulary crosswords — each clue a definition, a sentence, or a grammar hint. Available by CEFR level, playable in the browser.

VocabularyGrammarLeveled A1–C1

Research Section

Beyond practice tools, Library Universe hosts a dedicated research area: AI political bias surveys, flashcard efficacy studies, and article comprehension analysis.

AI biasMedia literacyLearning science

Architecture

Built for scale.
Designed for longevity.

Frontend

React Router v7TypeScriptTailwind CSS v4Radix UIVite

Backend & Data

Node 22 + ExpressPrisma ORMSQLite + LiteFSSanity CMSTigris (S3)

AI & Quality

OpenAI GPTPlaywright (E2E)VitestMSW (mocks)Sentry

Infrastructure

Fly.io (multi-region)DockerLiteFS (distributed SQLite)GitHub Actions CI/CDResend (email)

Editorial Infrastructure

Sanity CMS as the
editorial backbone.

All editorial content — articles, authors, flashcard decks, crosswords, political survey data — lives in Sanity. The app queries it via GROQ, a typed query language purpose-built for structured content.

  • Structured multi-language fields per content type
  • Author profiles with bio and article references
  • Portable Text rendering in React
  • Real-time comment writes via Sanity API
  • Image pipeline with Sanity image transforms

Content Types

articleauthorflashcardDeckflashcardcrosswordarticleCommentaiModelpoliticalSurveyRun

Query language

GROQ — typed, projection-based, safe. All queries are validated with Zod schemas on the server.

For Media Companies

Why this work is
relevant to you.

Multilevel content delivery

The same article at three reading levels is a model for editorial accessibility — reaching readers of different literacy, language background, or age group.

AI editorial tools

AI-assisted comment moderation, proofreading, and bias detection are technologies every digital newsroom will need to evaluate — I have already built working versions.

Headless CMS & GROQ

Sanity is widely adopted in media. Understanding structured content, editorial workflows, and API-driven publishing is core to modern digital journalism products.

"Library Universe is editorial technology applied to language learning — the same problems newspapers solve every day: content at the right level, for the right reader, with the right tools."

Brand Identity

Calm. Precise.
Academic, but warm.

Libre Baskerville (serif)Inter (sans)

Contact

Osman Cakir

Learn slowly. Learn deeply.