Anki

What Anki is

Anki is a flashcard program built around spaced repetition. Each time you review a card, you rate how well you remembered it, and Anki schedules the next review further or sooner. Since version 23.10 it includes FSRS, a modern scheduling algorithm that models your memory more accurately than the older SM-2 method and can reduce the number of reviews needed.

• Desktop: free for Windows, macOS and Linux
• Android: AnkiDroid, free and community developed
• iOS: AnkiMobile, a paid app whose sales fund development
• Sync: free through AnkiWeb
• Add-ons, media on cards (images, audio, code formatting) and support for very large decks

The desktop app is open source, with about 31,400 GitHub stars as of September 2026, and was still being actively developed that month.

Why it helps engineers

Long learning plans have a retention problem. You learn a sliding window pattern in week two, do not touch it again, and by week ten it is gone. Spaced repetition fixes exactly this by bringing each item back just before you forget it.

Useful card topics for engineers and students:

• Algorithm patterns and their triggers: "input is sorted and you need a pair: consider two pointers"
• Complexity facts: time and space for common operations and algorithms
• System design definitions: consistency models, caching strategies, load balancing approaches
• Language details you keep looking up
• Course material for university exams

What not to put on cards

Avoid full code solutions and long paragraphs. Cards should test one fact or idea you can recall in a few seconds. Understand the material first, then make cards. Cards made from things you have not yet understood become a chore you will abandon within two weeks.

How to build the habit

• Fifteen minutes a day, every day, ideally at the same time.
• Add a few cards per day, not dozens. Reviews grow with every new card.
• Enable FSRS in the deck options and keep the default desired retention unless you have a reason to change it.
• Suspend or delete cards that no longer matter.
• Write your own cards where you can. Shared decks are convenient, but making cards is part of learning.

Where it falls short

• It does not teach. It helps you keep what you already understand.
• The interface is dated and takes a little time to learn.
• Missing days hurts: reviews pile up. Keep daily sessions short to stay consistent.

Common questions

Is Anki free? Yes on desktop, Android and the web. The iOS app is paid.

Is it worth it for a short preparation of two weeks? Less so. Spaced repetition pays off over months.

Can I share decks with friends? Yes, decks can be exported and shared, and AnkiWeb hosts shared decks.

Best for: students and engineers learning over months who want to stop forgetting what they studied.