504 - Vocabulary Builder

Name: 504 - Vocabulary Builder
Rating: 4.8 (4595 reviews)
Author: Nefarius Apps

By: Nefarius Apps App

Word of the Day & Flashcards

Overview

Version:

8.12.4

Last updated: 2026-07-19

Features & Capabilities

504 Words is a language learning app that helps you master essential vocabulary through clear definitions, example sentences, and native pronunciation. Learn 504 high-utility words across English, German, and French with practical usage—perfect for real-world communication. The clean, ad-free interface keeps you focused on learning.

Practice with built-in study modes: flashcards, multiple-choice quizzes, and listening games to boost memory, comprehension, and pronunciation. Track your progress, see mastered words, and tailor your pace to your level. More languages will be added, making it a scalable tool for daily practice anywhere.

User Growth & Download Statistics

App Education Games

By:

Nefarius Apps

Rating:

4.80

(4,595) 10 ratings

Version:

8.12.4 Last updated: 2026-07-19

Version code:

888528709

Creation date:

2019-02-15

Compatible devices:

Size:

62.11MB

URLs:

Website ,Privacy policy

Full description:

Source:

Apple Apps Store

Data ingested on:

2026-08-11

Compare stats and ranking:

Ranking

# 26,445 ▼ 56

Other rankings

#42 in improve keyword 34 ▼ 12

For Developers

Monetize with App Pass Boost with Extension Booster

Contact the developer

Chrome-Stats does not own this Apple app. Please use these information below to contact the Apple app developer.

Developed by:

Nefarius Apps

Apple Apps Store

https://apps.apple.com/us/app/504-vocabulary-builder/id1452101398

Website:

https://nefarius.co

User Reviews

Users praise the app for convenience and vocabulary practice, especially the card-based format and contextual sentences. However, several issues recur: pronunciation audio often fails or uses the wrong voice; premium pricing and late-access lockouts frustrate users; and updates bring bugs, lag, and UI problems. Overall, the app is useful for learning, but reliability and pricing clarity need improvement.

Pros

Very convenient to learn and review vocabulary anywhere on a mobile device, serving as a practical substitute for the book.
The practice content helps with learning vocabulary and usage in context (sentences).
Card-based format with examples and synonyms supports effective learning.
General positive sentiment from users, with some reviewers calling it among the best vocabulary apps they have used.

Cons

Pronunciation and audio features often do not work correctly, with TTS using an English voice or failing to play pronunciation.
Content and lessons become locked behind premium, with confusing pricing and reports of paying for access to later lessons.
Bugs and stability issues in updates, including lag, display problems, and navigation quirks, plus missing PDFs or features on some devices.

Recent reviews

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.