What Is It?
Flipnem is an Anki compatible Flashcard platform.
The browser turns out to be a good home for flashcard study. A few things you get for free:
- Image zoom — tap or click any image to see the full detail
- Infinite device support — if it has a browser, it works. Phone, tablet, laptop, TV — doesn't matter
- Instant sharing — share a deck with anyone via a link, no install required
- No sync headaches — your collection lives in one place; every device just connects to it
- Always up to date — no app store updates, no version drift across your devices
The Engine
Initially I used rslib — the open-source, AGPL-licensed Rust library that powers Anki Desktop. It worked amazingly. It let me offer Anki-quality card review to potentially thousands of concurrent users, all running the same proven engine.
Then, as I got closer to shipping, I started thinking hard about that AGPL license. It's a gray area, but I decided not to risk it.
So I pointed Claude at the problem and he reimplemented the scheduling engine from the ground up — working from the public FSRS specification rather than the Anki source. We are FSRS-only for now, and we swapped the storage layer from SQLite to PostgreSQL, which came naturally from building for multi-tenant use from day one.
On Syncing
At first, syncing felt like table stakes.
But, the deeper I got into trying to support it, I realized that syncing was not a part of Flipnem's value add. When all your collections live in one system, you just log in from any device and pick up where you left off. The sync concern disappears entirely.
What doesn't work yet
Decks that use Image Occlusion note types are not currently supported. Image Occlusion cards will import but don't dependably render correctly.
Decks that rely on JavaScript inside card templates also won't behave as expected. For security reasons, scripts embedded in card HTML are stripped before rendering. Most decks don't use this, but some advanced community decks do.
Everything else — images, audio, video, MathJax, type-in-answer, and cloze deletions — works fine.
What I'm excited about
Sharing
The ability to instantly share a deck is intriguing. Think of a teacher — with Flipnem they can share a deck with all their students. Students can access it on the free tier and get real value out of it immediately.
Hashcards
Flipnem supports a simple plain-text format called Hashcards for creating decks by hand. This is an amazingly simple Markdown-based format. I think it will be great for folks who want to author their own cards quickly.
API and AI integration
AI is absurd, and its ability to generate flashcards is too. Having your own online repo that it can dump into is quite nice. You can literally go from an idle AI conversation to having a subject set up and ready for you to start memorizing.
Give it a spin
Please take Flipnem for a spin and let me know what you think.
- Sam