Anki: The Open-Source Spaced Repetition Flashcard Program

TL;DR: ankitects/anki is the upstream for Anki, the spaced repetition flashcard program. Rust codebase, 30,890 stars, and the canonical self-hosted study tool with sync through apps.ankiweb.net.

What it is

ankitects/anki describes itself as “Anki is a smart spaced repetition flashcard program.” It lives under the ankitects organisation, the language is Rust, the license is NOASSERTION (the upstream has not pinned an SPDX identifier), and the repository has 30,890 stars and 3,213 forks. It is not archived, and the homepage is https://apps.ankiweb.net.

Anki has been around long enough that the GitHub repo is the modern continuation of a project that predates the platform.

What it does well

Spaced repetition only works if the schedule is consistent and the friction is low. Anki has had years to tune both.

• Cross-platform clients. Desktop builds for Windows, macOS, and Linux, plus a mobile client that syncs through AnkiWeb.
• Rust core. The recent move to a Rust engine gives the project a much smaller memory footprint than the original Python implementation, which matters for users with large decks.
• Mature ecosystem. Add-ons, shared decks, and sync infrastructure are well-established. For most languages there are pre-made decks that new users can pull in immediately.
• Self-hostable sync. Although the default AnkiWeb sync is hosted, the protocol is documented and self-hosted alternatives exist for users who prefer not to use the hosted service.

How to try it

The desktop client is downloadable from the homepage; for the source build:

git clone https://github.com/ankitects/anki.git
cd anki
# build instructions live in the repo and follow the standard Rust toolchain

Once installed, decks can be created from scratch or imported from the shared deck index.

When it fits, and when it doesn’t

Anki fits anyone who wants to retain knowledge over months and is willing to maintain a daily review habit. It is less attractive if you need a friction-free capture experience that does not require scheduling reviews, or if your study material changes fast enough that long-interval recall does not help.

30,890 stars plus a multi-year track record make Anki the de facto reference implementation for spaced repetition software.

Source and Accuracy Notes

• Project page: https://github.com/ankitects/anki
• Source repository: ankitects/anki (verified via GitHub API html_url)
• License: NOASSERTION (GitHub could not auto-detect an SPDX identifier)
• Stars at time of writing: 30,890
• Language: Rust
• Homepage: https://apps.ankiweb.net