Immersion Reader - E-Reader & Dictionary App

Hello everyone, I would like to share an E-Reader app Immersion Reader, available for iPhone and IPad.


For a long time there hasn’t been a Yomichan tool on iPhone for reading. In light of this, I made a small prototype in a few weeks and eventually turned it into a full app.

First of all, I made sure the lookup process was simple and fast.

A quick tap on the word and the dictionary pops up. No need to long press, highlight, or drag a bubble around.

To start reading, tap on the reader page and select an EPUB file from your phone.

Here’s a guide on how to convert your Japanese books to EPUB.

You can install your own Japanese dictionaries, including monolingual dictionaries and frequency dictionaries. Here’s a link to several free bilingual dictionaries.

Unlike Yomichan, the search function also allows you to search in reverse for bilingual dictionaries, for example, using English to look up Japanese words.

To add your words to Anki, tap on the top right corner to export your words to the AnkiDojo format. Transfer the file to your computer with AirDrop or cable, and then sync it to Anki through AnkiDojo. There’s a 3 minute walkthrough on how to set it up, and feel free to reply to this thread should you have any problems.


Upcoming Features

  • Audio Books
  • Read Along Books
  • Browser Done!
  • RSS


How do I add books?

You can buy books from and bookwalker.

Here’s a guide on how to convert your Japanese books to EPUB.

How do I install dictionaries?

You can install your own Japanese dictionaries, including monolingual dictionaries and frequency dictionaries. Here’s a link to several free bilingual dictionaries.

Is this available on Android?

Not yet, but you can consider using kiwi browser + Yomichan + ttu.

You can also download this all-in-one android app.

Is this a free app?

Immersion Reader is free and open source.

There is a one-time payment to unlock the browser feature. This helps pay for the yearly apple’s subscription fee to keep the app ad-free for everyone.

If for some reason you can’t pay and would like to access the browser feature, you can find the source code here and build the app for your phone.




March 26, 2023

  • You can now save vocabulary in my dictionary screen.
  • Added cookie editor to browser.
  • Fix to pitch visuals.

March 18, 2023

  • Keep screen active when reading

March 11, 2023

  • You can select local html files for the browser.
  • Performance Improvements

March 8, 2023

  • Reader Statistics
  • Performance Improvements
  • Added Heatmap calendar
  • Improved tap detection

Dec. 29, 2022

  • Reader full screen support
  • Ad-block support for browser
  • Daily reading goal

Dec. 16, 2022

  • Added browser (in-app purchase)
  • Bug Fixes

Nov. 27, 2022

  • Added discover page for Aozora books
  • Bug Fixes


Ooh I’m intrigued. I read a decent number of books as EPUB on iPad, and I have a book club reading to work on today with one of them so I’ll give this a try! :smiley:



It will look kind of funny on the iPad right now since I haven’t released the iPad (universal) version to the app store, but I will definitely update it soon!


Ah, I did notice some odd issues when I tried it a bit ago. Would it be helpful for me to screenshot what I’m seeing or would it be better to wait and try later?

1 Like

Sure. It might take a few days for me to upload the newer version and have it approved by the app store.

1 Like

For reference, my system version is 15.5 and I’m using a 5th generation iPad.

Putting the pics behind curtains to avoid a giant post :sweat_smile:

Everything I highlight gives me double dictionary entries

All images are hidden as spoilers

I noticed some weird text handling

Same section from iBooks for comparison. Note 第一章

I should mention this book is using I, II, III, IV for counting chapters

Also I didn’t notice a way to scale down the font - it’s quite big by default.

No worries on time. I appreciate you’re putting your time into developing such a useful app! Having to fiddle around with the text selector is such a pain sometimes.

This patch is included in the next release. Thanks for bringing it up anyway! :smile:

This is a setting in TTU that you can set from the cogwheel in the top right corner.

TTU: Blur Image

Try changing the font family of both groups in TTU settings to Noto Sans JP

TTU: Font Family

1 Like

I didn’t even realize there was a cog at the top :sweat_smile: I’m used to tapping anywhere on the screen (excluding buttons of course) to show hidden menus, but I imagine that’s trickier to do with the text selection that’s going on.
That said, I can’t seem to access the menu you’re showing even after clicking the cog. I get a view of my loaded books and I still have a cog available to click, but it just turns from grey to white but otherwise doesn’t react. There is a book icon overlapping the page with the arrow as well. Screenshot included incase it’s helpful at all, but I think I’ll wait til the next update so that I don’t flood you with bugs you’re probably already aware of :sweat_smile:


1 Like

Hey, just want to say thank you for developing this, it solves a problem I’ve been having with using my iPhone as a reading tool during commuting. Normally I use TTU & 10Ten plugin on safari to act as a substitute Yomichan (iPad), however this doesn’t work on IPhone as for some reason the books won’t load into TTU. However the idea alone of being able to import our own dictionaries is amazing, thank you! Looking forward to testing this out.


It would be really nice to have PDF support so that we could read manga using mokuro2pdf.

When you say you are looking into adding browser support do you mean that you plan to add support for going to web pages? That would actually unlock almost everything. Would really love to see that implemented.

Also proper ipad support would be great

Yes, it would take a bit more time to implement browser features, and I intend to add that as a paid feature to support its development and pay for the yearly Apple developer fees.

Yes I can add pdf kit as well, but once the browser is ready you can basically just use the web to open most files.

1 Like

i would definitely pay for web access

1 Like

Which additional dictionaries would you recommend, where would I get them
And how do I add them in the app?

You can find some of the bilingual dictionaries here.

I recommend sticking to the included Japanese-English dictionary plus your native language dictionary.

For monolingual dictionaries you would need to build your own from EPWING here. You might find some online by searching with entires like “daijirin yomichan”, “大辞林 yomichan”, or “monolingual dictionary”. Download at your own risk.

To add a dictionary, go to Settings > Dictionaries > Edit > “+” icon. You can select the zip file from your phone or on iCloud.


Thanks for the slide animation setting. It really helps making it feel more snappy for people like me that do a lot of queries.

Also I submitted a ticket on github. Probably you prefer them over there to keep better track.

1 Like

I’m considering adding more Anki integration and flashcard features to the app.

If you use the app or plan to use the app, let me know which you would prefer.

  • [Current System] Export and sync through PC
  • [Using Url Schemes] Add to Anki Mobile on your phone without exporting
  • Review using Immersion Reader’s flashcard system and avoid Anki.

0 voters

1 Like

Please, not another SRS app :rofl:


What I had in mind was more like Kindle flashcard reviews than a fullblown app, but I will focus my efforts elsewhere for now. :smile:

I have a working concept for book highlights. Instead of simply the Kindle version of “20 people have highlighted this”, I want to allow users to add their own comments and discuss with other readers. This could be great for hard-to-understand words or sentences.

Since a lot of beginners read from the same pool of books (魔女の宅急便、コンビニ人間), this could be an important resource and source of motivation.

In regards to matching different book versions, I could implement an ISBN/book name/chapter/page matching algorithm, and that could be a discussion by itself.

1 Like

Wow, this is amazing. Thank you so much for making it.

1 Like