Words on Repeat VS Diffyn

Words on Repeat's answer

Words on Repeat is the only vocabulary app that combines AI-powered content extraction with FSRS spaced repetition - all for free.
Paste any URL, upload a PDF, or import YouTube subtitles and AI extracts a study-ready flashcard deck with translations, example sentences, and grammar notes in seconds. No other tool offers all four input methods with automatic vocabulary extraction.

What sets it apart:

• AI extraction from real content. Turn any article, PDF, or YouTube video into flashcards in seconds
• Grammar notes on every card. Contextual tips like "irregular past tense: fui/fue/fueron" or "use por for duration, para for deadline" - no competitor provides this
• 185+ curated public decks in 12 languages, organized by CEFR level (A1–C2)
• Web-first PWA - no app store download, works offline, installs to your home screen on any device

Diffyn's answer:

Addresses workflow and change management on LLM prompts, provide teams with traceability and visualization of tests across multiple models, provide deeper understading into efficiency of these prompts.

Words on Repeat's answer

You get the most complete free tier of any flashcard app:

• FSRS spaced repetition - the same algorithm Anki uses, scheduling reviews right before you'd forget
• 7 quiz modes - flashcards, multiple choice, typing, listening, matching, true/false, speed review
• 185+ curated decks across 12 languages with grammar notes on every card
• Progress analytics, daily study goals, push notification reminders, and dark mode
• No ads, no paywall - everything works out of the box

How competitors compare:

• Quizlet charges $36/year and still doesn't offer true spaced repetition
• Anki is free but requires hours of setup, add-on hunting, and template configuration to get a comparable experience
• Words on Repeat gives you all of that in under 30 seconds, with zero configuration

Diffyn's answer:

Diffyn is the platform that specializes on both change management and multi-model analysis.

Words on Repeat's answer

Which are the primary technologies used for building Words on Repeat?

• Backend: TypeScript, Express.js, DB - fast, lightweight, no heavy infrastructure
• Frontend: Vanilla JavaScript - no framework, no bundler, which keeps page loads instant
• Spaced repetition: ts-fsrs library - the same FSRS algorithm powering Anki's latest scheduler
• AI extraction: OpenAI API for content parsing, translation, and grammar note generation
• Offline support: Progressive Web App with service worker caching
• Hosting: AWS

Diffyn's answer:

React, Next.js, POSTGRESQL

Words on Repeat's answer

Language learners who want to build vocabulary from real content — articles, YouTube videos, podcasts, textbooks - rather than drilling disconnected word lists.

Our typical users:

• Intermediate learners (B1–B2) who've outgrown Duolingo but find Anki too complex and Quizlet too limited
• Quizlet refugees who hit the paywall and want a free alternative with better study tools
• Anki users who want a modern interface without sacrificing algorithm quality
• Self-taught learners who study from YouTube, news articles, and PDF textbooks

Supports 12 languages: Spanish, French, German, Italian, Portuguese, Japanese, Korean, Chinese, Dutch, Polish, English, and Swiss German - with decks organized from beginner (A1) to mastery (C2).

Diffyn's answer:

Professionals incorporating LLMs or AI tools in their workflow and wants to keep track of changes and test their prompts.

Words on Repeat's answer

I spent two years building SuperMemo collections, then switched to Anki, then tried Quizlet when I wanted something simpler. When Quizlet locked study modes behind a $36/year paywall, I decided to build what I actually wanted:

• Modern spaced repetition with a clean interface
• No paywall on the core study tools
• The ability to extract vocabulary directly from articles and YouTube videos I was already consuming

Words on Repeat started as a personal tool for my own Spanish studies. I kept thinking "I wish I could just paste this article and get a deck" - so I built exactly that.

It grew from a single Spanish deck into a platform with 185+ curated decks across 12 languages, 7 quiz modes, AI-powered extraction from any content source, and a community of learners studying everything from French A1 basics to Japanese C1 business vocabulary.

Diffyn's answer:

I started working on Diffyn when I notice that prompting has become an essential part of work across many industries. While there are version control platofrms like github, they are not designed for just prompt management are can be overkill such applications, it is also not integrated natively with various LLMs and relevant tools for users to validate ideas and visualise results properly.

Words on Repeat's answer

• Language learners studying Spanish, French, German, Italian, Portuguese, Japanese, Korean, and Chinese
• Students preparing for CEFR language exams from beginner (A1) to mastery (C2)
• Quizlet switchers looking for a free alternative with real spaced repetition
• Self-taught learners who build vocabulary from YouTube channels, news articles, podcasts, and PDF textbooks
• Expats and professionals learning a new language for work or relocation
• Language teachers who use the public deck library and deck sharing features with their students