Introducing Burnki: syncing burned items from WaniKani to Anki

I had a tough time falling asleep last night, and started worrying about how I’d probably forgotten a lot of my burned items on WaniKani. Let me explain.

WaniKani is a flash card website I use to learn kanji. It uses the spaced repitition system (SRS), which is a learning technique optimizing for long-term memory retention. It schedules reviews of kanji right before I forget them. Every flash card, or item, goes through several stages to eventually end up in burned, meaning that I’ve gotten the item right often enough that it’s considered memorized. Once an item is burned, it’ll never show up in your reviews again (unless you manually unburn it, which I never do).

The thing is, I don’t fully trust that I’ll remember said item in the long-term. I don’t get a lot of Japanese input. If I’m feeling studious, I’ll watch an immersion video, but outside of my Japanese lessons + homework and WaniKani, I don’t practice very often (I’m not the most effective Japanese learner, but that’s okay).

Another app that uses SRS is Anki. WaniKani comes with its own content, but with Anki, you can create your own content (or use content that others have made and shared online). I tried Anki a year ago, but wasn’t a big fan of it: it took up too much time and I didn’t retain much. Now that I’m a second year in, and learned more grammar, kanji, and words, I figured I’d give it another try (also, my new Japanese teacher quizzes us on Genki words weekly, and my tactic of cramming 30+words the day of the class wasn’t working). I’m enjoying the experience much more now.

So as I was tossing and turning in bed last night, I had an idea that I want to take all my burned items and put them in an Anki deck, and whenever I feel like it, I’ll go through a bunch of cards and hopefully keep my burned items on the burn list, instead of forgetting them. I wanted some sort of script or app that takes my burned WK items, creates an Anki deck, and makes sure to sync whenever I burn a new item.

You can extend Anki with custom add-ons, which are distributed on AnkiWeb. They’re Python modules that can hook into the program. With the help of Claude Code (I’m a TypeScript dev, not a Python dev!), I made Burnki: automagically sync your WaniKani burned items into an Anki deck.

Burnki syncs all burned radicals (the building blocks that kanji are made up of), kanji, and vocabulary from a given WaniKani account. All you need is an API key. Download instructions are here on AnkiWeb!

Not to get into the LLM/coding discourse too much, but this feels like a good vibe-coding usecase: it’s low-stakes and there’s a target audience of one person (moi!). Before, I’d either have to use someone else’s add-on (which is fine, but, they never quite work the way I want them to), or hack something together over the course of a few weeks. This didn’t take nearly as long, and I understand most of what’s happening with the code, because I got Claude to walk me through it before committing anything.

Burnki probably won’t change anyone else’s workflow, but it exists because I had a very specific problem and solving it felt pretty good, despite some of the reservations I have around AI. Maybe I’ll sleep a little better tonight :)