# 504 - Vocabulary Builder — Word of the Day & Flashcards > Language learning app for mastering essential vocabulary with games and progress tracking. (iPhone/iPad app by Nefarius Apps.) - Source: https://appshunter.io/ios/app/504-vocabulary-builder/id1452101398 (this page in markdown: same URL + `.md`) - Developer: [Nefarius Apps](https://appshunter.io/developer/1792473508) - Category: Education, Productivity - Price: Free with in-app purchases - Rating: 4.80/5 from 4,603 App Store ratings · 62 written reviews indexed - Age rating: 4+ - Requires: iOS 18.0 · 62 MB - Languages: American English, French (France), German (Germany) - Released: 2019-02-15 - Data updated: 2026-08-27 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/504-vocabulary-builder/id1452101398/reviews.md ## What is 504? Build your vocabulary with 504 Words – a smarter way to learn languages. 504 Words is a language learning app that helps you master the most essential vocabulary through clear definitions, example sentences, and interactive games. Whether you're learning English, German, French, or future supported languages, this app is designed to make your progress efficient and enjoyable. Learn the right words We’ve carefully selected 504 high-utility words for each language, focusing on real-world usage and practical communication. Every word comes with: - A clear definition - An example sentence - Native pronunciation Practice through interactive games Make learning fun and effective with built-in study modes: - Flashcards to test your memory - Multiple choice quizzes to reinforce understanding - Listening games to improve your pronunciation and recognition skills These game modes make it easier to retain new words and stay engaged every day. Track your progress Stay motivated with performance tracking tools. Monitor the words you've mastered and focus on areas where you need improvement. Great for daily practice and long-term learning. Multi-language support Start with English, German, and French. More languages will be added soon. Whether you're a beginner or refreshing your knowledge, the app adapts to your level and pace. Designed for all learners 504 Words offers a clean, intuitive interface suitable for learners of all ages. Use it at home, in class, or while traveling. No ads, no distractions—just focused learning. Download 504 Words today and take the first step toward confident communication in any language. https://nefarius-apps.github.io/504/privacy-policy https://nefarius-apps.github.io/504/terms-of-use ## Key features - Essential vocabulary selection - Clear definitions and example sentences - Native pronunciation audio - Interactive learning games (flashcards, quizzes) - Progress tracking tools - Multi-language support ## Pricing and in-app purchases Base price: Free. **Subscriptions** | Subscription | Price | Period | | --- | --- | --- | | Weekly Pro Membership | $8.99 | per 7 days | | Monthly Pro Membership | $17.99 | per month | | Monthly Premium Membership | $19.99 | per month | | Weekly Premium Membership | $9.99 | per 7 days | | Yearly Premium Membership | $59.99 | per year | | Premium | $9.99 | per month | | Premium | $9.99 | per month | | Premium | $4.99 | per 7 days | | Premium | $9.99 | per 7 days | | Premium | $34.99 | per year | | Yearly Pro Membership | $59.99 | per year | | Premium | $9.99 | per month | **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Lifetime Access | $79.99 | one-time | ## What do users think of 504? Overall sentiment: neutral **Pros** - 🚀 Easy to learn - 👍 Useful vocabulary practice - 🚀 Convenient for learning on the go **Cons** - 🐛 Bugs and glitches in latest version - 🔒 Concerns about data tracking - 🔊 Issues with pronunciation and audio **Commonly reported bugs** - Pronunciation not working in latest version - Lessons for second half of book blocked behind paywall - Compatibility issues with older devices **Most requested features** - Add part of speech for each word - Include a note box for personal examples - Add dark mode option ## Recent user reviews (10 of 62) All indexed reviews: https://appshunter.io/ios/app/504-vocabulary-builder/id1452101398/reviews.md ### 1/5 — English Audio Reading French Words Not Good *2025-12-26, version 8.5.0* I set up the app to ostensibly teach me intermediate-level French vocabulary. The French words appeared in individual cards with French synonyms and example sentences. All fine so far. But when I pressed the audio pronunciation button next to the French vocab words, the built-in text-to-speech reader was an English voice which wrecked the pronunciation of the French words. This made the app essentially useless for my purposes. Unfortunate to say the least. ### 5/5 — Excellent Vocabulary Learning App! *2025-08-14, version 8.0.0* This is one of the most useful apps I’ve used to improve my English vocabulary. The word of the day feature makes learning both fun and consistent, helping me practice regularly. The interface is clean, easy to use, and the content is high-quality. Highly recommended! ### 3/5 — doesn't work *2025-02-14, version 8.0.0* I can't open the app. what's the problem? ### 5/5 — Questions *2024-12-17, version 7.7.0* I downloaded this app like 2 minutes ago tbh but i have some questions: 1: is there like a premium that you have to pay for? Because I read all the reviews (i like reading reviews for some reason) and some of them complained about premium and I downloaded it expecting to see premium or something but it just said you are already premium so I'm confused on that, 2: the words/lessons, how is words like legend, amend, resign, etc in the last/hardest(????) lesson and words like qualify, abandon, oath, etc in the first/easiest(????) so I'm really confused ### 1/5 — Terrible *2024-08-10, version 7.4.0* Please I’m waiting for new update . This app doesn’t even open properly! ### 5/5 — 504 review *2024-06-04, version 7.1.0* It’s the best app that I have used in my entire life, I really appreciate creating such an amazing app ### 5/5 — Fix problem *2024-05-23, version 7.1.0* Hello,it is great app.However,I updated the software but it doesn't work anymore ### 1/5 — Data tracking *2024-05-22, version 7.1.0* Sketchy they want to track you across the different apps and websites you use: your user id, device id, usage data, and diagnostics. Instant delete. Edit: don’t believe their response, they would not be required to ask for consent if they didn’t track your data across services owned by other companies. Edit again: the person responding to reviews clearly doesn’t understand data tracking across apps and websites from other companies, sketchy when your app is doing it and it’s literally disclosed on your product page ha ### 1/5 — Data tracking *2024-05-20* Sketchy they want to track you across the different apps and websites you use: your user id, device id, usage data, and diagnostics. Instant delete. Edit: don’t believe their response, they would not be required to ask for consent if they didn’t track your data across services owned by other companies. **Developer response:** Hello, thanks for the review. Allowing tracking doesn't mean the app can access all the data on your phone you have. It means the app can identify you ONLY in 504 app during the usage of the app. It helps us to show you the best content. Edit: Hello again. No mobile application can see the data of another mobile application. This is not possible with Apple products. This applies both to us and to other mobile apps. ### 1/5 — Data tracking *2024-05-17* Sketchy they want to track you across the different services you use. Instant delete. **Developer response:** Hello, thanks for the review. Allowing tracking doesn't mean the app can access all the data on your phone you have. It means the app can identify you ONLY in 504 app during the usage of the app. It helps us to show you the best content. ## Frequently asked questions about 504 ### What does the 504 Words app do? This app helps you build your vocabulary by focusing on essential words for effective communication. It provides clear definitions, example sentences, and native pronunciation for each word. You can also practice what you learn through interactive games and track your progress. ### What are the key features of 504 Words? Key features include a curated list of high-utility words, detailed definitions, example sentences, native pronunciation, and interactive study modes like flashcards, multiple-choice quizzes, and listening games. It also offers progress tracking and multi-language support. ### Is 504 Words free to use? The app is free to download and use, but it offers in-app purchases. This means you can access core features for free, with options to buy additional content or features. ### What languages does 504 Words support? Currently, the app supports English, German, and French. The developers plan to add more languages in the future, expanding its utility for a wider range of learners. ### Who is the target audience for this app? The app is designed for all learners, from beginners to those looking to refresh their knowledge. Its intuitive interface and adaptive learning approach make it suitable for users of any age who want to improve their language skills for real-world communication. ## Version history (last 5 releases) ### 8.12.4 — 2026-07-19 We keep the app updated to provide you with the best user experience! ### 8.12.3 — 2026-06-29 We keep the app updated to provide you with the best user experience! ### 8.12.2 — 2026-06-29 We keep the app updated to provide you with the best user experience! ### 8.12.1 — 2026-05-14 We keep the app updated to provide you with the best user experience! ### 8.12.0 — 2026-04-22 We keep the app updated to provide you with the best user experience! ## Apps similar to 504 | App | Rating | Price | Category | | --- | --- | --- | --- | | [Vocabulary - Learn words daily](https://appshunter.io/ios/app/vocabulary-learn-words-daily/id1084540807) | 4.8 (214,742) | Free | Education | | [Word of the Day・Vocabulary](https://appshunter.io/ios/app/word-of-the-dayvocabulary/id987136347) | 4.7 (38,771) | Free | Education | | [Vocabulary Builder by Atlas](https://appshunter.io/ios/app/vocabulary-builder-by-atlas/id1438344260) | 4.8 (12,333) | Free | Education | | [English Cards: Vocabulary](https://appshunter.io/ios/app/english-cards-vocabulary/id1658981786) | 4.5 (60) | Free | Education | | [ELSA Speak - English Learning](https://appshunter.io/ios/app/elsa-speak-english-learning/id1083804886) | 4.8 (111,707) | Free | Education | | [WordUp - Vocabulary Builder](https://appshunter.io/ios/app/wordup-vocabulary-builder/id1365078730) | 4.8 (13,831) | Free | Education | ## More apps by Nefarius Apps - [Psychology Dictionary](https://appshunter.io/ios/app/psychology-dictionary/id1500147226) - [Workout: Gym Tracker & Planner](https://appshunter.io/ios/app/workout-gym-tracker-and-planner/id1636036028) - [Bluescan: Lost AirPod Finder](https://appshunter.io/ios/app/bluescan-lost-airpod-finder/id1645712949) - [Artist AI Image & Photo Filter](https://appshunter.io/ios/app/artist-ai-image-and-photo-filter/id1662333649) - [Silter: SMS Spam Blocker](https://appshunter.io/ios/app/silter-sms-spam-blocker/id6466715635) All apps by Nefarius Apps: https://appshunter.io/developer/1792473508 ## Related topics [app builder free vocabulary](https://appshunter.io/ios/topics/app-builder-free-vocabulary) · [essential education](https://appshunter.io/ios/topics/essential-education) · [vobolio](https://appshunter.io/ios/topics/vobolio) · [sat vocabulary builder](https://appshunter.io/ios/topics/sat-vocabulary-builder) · [stoney vocab builder 2](https://appshunter.io/ios/topics/stoney-vocab-builder-2) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-27.*