How to Set Up a Plain-Text Flashcard System

Zo Computer gives you a personal cloud server where you can run code, build projects, and host services. Every Zo comes with a built-in terminal and file system you can use right from your browser—plus an AI assistant that can help you set things up.

One thing you can run is a spaced repetition system for learning. If you've never heard of spaced repetition, it's a learning technique where you review information at increasing intervals—seeing a flashcard right before you'd forget it, then waiting longer before the next review. It's one of the most effective ways to commit things to long-term memory, backed by decades of cognitive science research.

Why spaced repetition works

Spaced repetition takes advantage of how memory works. When you encounter information at just the right time—not too soon, not too late—you strengthen the neural pathways that encode it. Review too often and you waste time. Review too late and you've already forgotten. The "spacing effect" optimizes this timing.

People use spaced repetition to learn:

• Languages — vocabulary, grammar patterns, phrases

• Medicine — anatomy, pharmacology, diagnoses

• Programming — APIs, syntax, algorithms

• History, law, music theory — anything with facts to remember

The most popular spaced repetition app is Anki, which has been around since 2006. But Anki stores your cards in a database, and some people prefer something simpler.

Hashcards: flashcards as plain text

Hashcards is a newer spaced repetition system by Fernando Borretti that takes a different approach: your flashcards are just markdown files in a folder.

A deck looks like this:

Q: What is the capital of France?
A: Paris

Q: What year did World War II end?
A: 1945

C: The mitochondria is the [powerhouse] of the cell.

That's it. Q: and A: for question-answer cards, C: with [brackets] for cloze deletions (fill-in-the-blank). No special format, no database—just text files you can edit with any editor, sync with Git, and back up however you like.

Hashcards uses FSRS (Free Spaced Repetition Scheduler), the same modern algorithm now available in Anki. It's more accurate than older algorithms at predicting when you'll forget something.

Why plain text matters

Storing flashcards as markdown has real advantages:

• Edit with any tool. Use VS Code, Vim, Obsidian—whatever you prefer. No proprietary editor.

• Version control. Put your cards in a Git repo. Track changes, branch experiments, collaborate.

• Generate cards programmatically. Write a script to turn a CSV of vocabulary into a deck, or use an LLM to create cards from your notes.

• Portable forever. Markdown is a 20-year-old format that will outlast any app. Your learning data won't be trapped.

• Share on GitHub. Make your flashcard collection public for others to learn from.

As Borretti writes: "Markdown files in a Git repo gives me a level of ownership that other approaches lack."

Setting up hashcards on Zo

Zo has a setup skill that installs and configures hashcards for you. In Zo chat:

Within a few minutes you'll have:

• Hashcards installed and running at https://srs-yourname.zocomputer.io

• A flashcards directory at /home/workspace/flashcards/ with a sample deck

• A persistent service that auto-restarts if it crashes

The skill handles installing Rust (hashcards is written in Rust), building from source, creating directories, and registering the service. You don't need to touch a Dockerfile or configure a reverse proxy.

Creating flashcards

Once hashcards is running, create .md files in /home/workspace/flashcards/. Each file is a deck.

Basic question-answer cards:

Q: What does FSRS stand for?
A: Free Spaced Repetition Scheduler

Cloze deletions (text in brackets is hidden during review):

C: [Spaced repetition] is a learning technique that involves reviewing information at [increasing intervals].

You can also add images, audio, and LaTeX math. See the hashcards documentation for the full syntax.

Tip: Ask Zo to help create flashcards:

Hashcards vs Anki

Both are excellent tools. Here's how they compare:

• Anki — The gold standard. Massive plugin ecosystem, mobile apps, cross-device sync. Uses a database format. Best if you want polished apps and don't mind the complexity.

• Hashcards — Plain-text storage, modern FSRS algorithm, minimal interface. Best if you value simplicity, version control, and ownership of your data.

• Mochi — Markdown-based like hashcards, with a more polished interface. Cloud-hosted with a subscription, or self-hostable.

• RemNote — Combines note-taking with flashcards. More complex, aimed at knowledge management.

If you're happy with Anki, there's no need to switch. But if you've been frustrated by Anki's complexity, or you want your flashcards in Git alongside your notes, hashcards is worth trying.

What else can you run on Zo?

Hashcards is one of many tools you can self-host on your Zo Computer:

• Workflow automation like n8n

• VS Code in your browser with code-server

• Remote development with your favorite IDE over SSH

• Databases like PostgreSQL, SQLite, or Redis

• Websites and APIs you build

Your AI assistant can help you set up and manage any of these.

Resources

• Hashcards on GitHub — Source code and documentation

• Hashcards: A Plain-Text Spaced Repetition System — Fernando Borretti's blog post explaining the design

• Hacker News discussion — Community reactions and ideas

• Zo hashcards setup skill — One-click installation

• FSRS algorithm — How the scheduling works

• Augmenting Long-term Memory — Michael Nielsen's essay on using spaced repetition effectively