Lag and latency increase during long study sessions

I’ve been having a problem over the past few weeks that seems to have gotten worse, so I wanted to ask about it. When I first boot up the website to do my reviews, the browser is very responsive, but the longer I study, the worse it gets. I will type my answer and have to wait for a second or two to see it appear on the screen. Then when I hit enter to confirm, I have to wait another 1-2 seconds to see if I got it correct or not. It’s really frustrating and it’s slowing my review speed down (I’ve been a bad language studier and have 300+ reviews right now >.>)

Has anyone else experienced this? If so, what did you do to fix it? I’m running Windows 10 and Chrome. The only extension I’m running is the WaniKani Override. Refreshing the page seems to fix the issue a bit, but I don’t want to be refreshing the page after every 20-30 reviews.



Try browsing other sites. Are they slow too? If yes, the problem is your internet connection. If not, then the problem could be WK.

I actually have this with long lesson sessions. It becomes so bad sometimes that my browser tab crashes. Never had it with reviews though.


How many items do you learn per session? Is it more than 5?

My sessions are always 5 lessons long, but when sometimes when I do long session hauls, after about 3 to 4 5 lesson sessions, I usually have to wait for a long time until I see something change, which at some point will last longer than 20 seconds and my browser will crash. After that I have to restart the lessons in a different tab and continue on until the browser tab has crashed again after 3-4 5 lesson sessions.

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Interesting. Let’s see what @viet or @oldbonsai say about this (both OP’s review and @Pep95’s lesson problems)

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Yes, I have seen that. My guess is that the javascript leaks memory, and especially on small devices that becomes very noticeable (eg. on my first gen ipad mini). It usually starts to become a nuisance after about 50 or so reviews, and seems to be worse the more errors you have made.


I’ll try to answer more of these questions.

This happens on lessons AND reviews. I am not experiencing latency on other websites, and I have a fiber connection so I think I’m good on that front. As a test I redownloaded firefox and it seems to run perfectly fine on that browser. Maybe Chrome is just being a big ol’ resource hog and is getting bogged down by other things. I don’t have more than 2-3 tabs open though. It’s E-mail, Wani-Kani, and Twitter… that’s it.

I have a temporary solution, but ideally I would like to not have to use a separate browser for Wani-Kani if I can avoid it.

PS: I installed all of my old third party plug-ins on Firefox and it seems to be running like a dream. On Chrome the issue still happens even with only Override on.

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Yes, I have the same situation. It even happens when I only have one tab open. Weirdly enough, it doesn’t always happen. This morning I did 44 lessons without any issues.

I’ve had this after hundreds of reviews. I remember talking to rfindley about it well over a year ago, but he had no idea what could cause it

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Are you also using Chrome?

It would be interesting to test this with various browsers because it could be the browser engine Blink, which is now used also for other browsers such as Edge and Vivaldi.

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Indeed I am

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I use Chrome as well

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Yeah I experienced this a lot. Ans no, if has nothing to do with the internet connection, it’s definitely a Wanikani problem.

I’ve been reading in the past several weeks that the Firefox team optimised the browser so it runs faster, especially compared to Chrome.

However, this still doesn’t explain why Chrome is slow. The fact that it doesn’t start slow and only gets slower over time does point to a possible memory problem.

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Chrome used to to such a lightweight browser too, but lately it’s quite the memory hog. For now it’s working flawlessly on Firefox, so I guess I start using firefox again at least for Kanji Study. Kind of a bummer, but if it works, it works. shrug


If this helps debug the problem, I’ve been using mainly Chrome for WK lessons/reviews too and I haven’t experienced any latency, even when I leave the session open and come back to it later (about 10 minutes later). However, my review sessions almost never exceed 40 items because I use the “wrap-up” button.

Latest version of Chrome on Linux and Windows 10. Once every 2 or 3 months I fire up my old MacBook Pro and I also use Chrome there to do WK reviews. No problems so far.

Spying on people must take a lot of computer resources :sweat_smile:. Using Firefox is a better choice regardless of performances (that are indeed much better anyway, lately) :wink:

No, it happens with Safari on iOS also (and the built-in browser for Mobile Allicrab which probably is also a stripped down Safari).

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I’ve had this issue on my old Android tablet, but I always blamed it on the device being old :thinking: Can’t say it’s happened on my PC though… I wonder what could be going on.