Reddit discussion here: https://www.reddit.com/r/LearnJapanese/comments/1phbsk4/i_te... (147 comments)
My app: https://reader.manabi.io
I quit my job a couple years back to work on this app full-time, as well as its companion flashcard app, Manabi Flashcards. The goal is to help you learn through immersion and eventually replace some of your flashcard reviews time with reading (once I finish auto-reviews for flashcards)
What's special about it? Manabi Reader became popular as an Japanese-focused alternative to services like LingQ in that it locally tracks and analyzes all the words and kanji you read and study. It shows you which words are new and which you're currently learning via flashcards, so you can easily find content that suits your level and see what flashcards to prioritize adding.
The pricing is also unique: students or low-income earners can elect to pay less, without verification. This has helped with word of mouth growth.
It also passively accumulates an on-device (and in your personal iCloud) corpus of example sentences from your reading. It’s also one of few ways to mine sentences including pitch accent directly into Anki on iPhone.
I had built this part-time while working over many years (starting with flashcards and then the reader app) but going full-time gave me the time to do a full rewrite: SwiftUI, native iOS + macOS, and an offline-first architecture that syncs with iCloud and my server in the background.
Although it has an optional companion SRS algorithm (FSRS) flashcard app, it's also a popular choice for mining Anki cards. This works with AnkiMobile on iOS and AnkiConnect on desktop.
You can use it like a web browser for the web, or subscribe to RSS feeds. It comes with a bunch of curated content by level. Recently I added EPUB support, pitch accents, and note-taking with todos.
I'm now almost done adding a manga mode via Mokuro, and Netflix/streaming video support via realtime captioning of audio streams. I've fine-tuned a manga-specific MLX-based OCR model (since Apple's OCR cannot tolerate vertical text) and have it working on iPhone, so I also plan to have it work on-demand and in-browser for sites like Bookwalker where you can purchase and find free manga.
In terms of growth, it's been mostly word of mouth so far - to scale this with UGC/influencer marketing I need to make it more beginner friendly. Currently it assumes you can read kana at least. But I have gotten interest from a bunch of influencers who already use the app or like it enough to recommend it generously (I'm starting with commission deals) so I am optimistic as I begin that campaign.