What is Obsidian?

An introduction to Obsidian, a free, local-first, and flexible note-taking application built on an open file format.

The Basics

Obsidian is a personal note-taking app that lets you write, organize, and connect your thoughts using Markdown—a simple, readable format for writing documents. Unlike many other note-taking applications, Obsidian stores your notes as plain text files on your computer, giving you complete control and ownership of your data.

Key Concept: Obsidian uses plain text Markdown files stored locally on your device. Your notes are yours to keep, not locked in a proprietary format or stored on someone else's servers.

Why Choose Obsidian?

Privacy First: Your notes stay on your device. Obsidian never sees your data unless you explicitly choose to use their optional services.
Data Ownership: Notes are stored as plain text Markdown files that you can read with any text editor, forever.
Free for Personal Use: Obsidian is completely free to download and use for personal note-taking.
Powerful Knowledge Management: Built-in features for linking notes, visualizing connections, and building a "second brain."
Fully Extensible: Thousands of community plugins and themes let you customize Obsidian to fit your exact workflow.
Works Everywhere: Available on Windows, Mac, Linux, iPhone, and iPad.

Core Features

1. Note-Taking with Markdown

Write your notes using Markdown, a lightweight format that's easy to read and write. Markdown makes your notes future-proof and portable. You can use headers, bold, lists, links, code blocks, and more.

2. Internal Linking (The Most Powerful Feature!)

Unlike typical note apps, Obsidian lets you create links between your notes using a simple syntax: [[note name]]. This turns your flat list of notes into a web of connected ideas—sometimes called a "second brain" or "digital garden."

Example: You can write a note about "Research Methods" and link to specific pages like [[Literature Review]] or [[Quantitative Research]]. When you click these links, you jump to those notes. Even better, those notes will show backlinks to your [[Research Methods]] note!

3. Graph Visualization

See your note network as an interactive visual graph. Each note is a node, and links between them are represented as connections. This helps you discover patterns and see the structure of your knowledge at a glance.

4. Backlinks and Unlinked Mentions

Every note automatically shows which other notes link to it (backlinks). Obsidian even suggests notes you might want to link (unlinked mentions). This makes it easy to find relevant connections you might have forgotten about.

5. Local Storage & Sync Options

Your vault (folder of notes) lives on your computer. You can also optionally use Obsidian Sync to access and synchronize your vault across multiple devices with end-to-end encryption.

6. Extensible with Plugins & Themes

Obsidian has a thriving ecosystem of community plugins that add features like templates, advanced searching, markdown preview, task management, and much more. You can also install themes to customize the appearance.

How Obsidian Compares to Other Apps

Feature	Obsidian	One Note	Apple Notes	Notion
Local Storage	✓	☓	✓ (encrypted)	☓
Internal Linking	✓ (powerful)	Limited	Limited	✓
Free	✓	Limited free	✓	Limited free
Open File Format	✓	☓	☓	☓
Extensible/Plugins	✓ (1000+)	Limited	Limited	✓
Best for Knowledge Games	✓ (research)	General notes	Quick notes	Complex databases

Key Concepts to Remember

Vault

A vault is simply a folder on your computer that Obsidian manages. It contains all your notes and a hidden .obsidian folder with settings. You can have multiple vaults for different projects or areas of your life.

Markdown

Obsidian's native format. It's plain text with simple formatting syntax (like # for headers). Markdown files are simple, readable, and future-proof.

Note (or Page)

A single Markdown file. In Obsidian, each file is one note. You can create as many as you want.

The Graph

A visual representation of how your notes are connected. It's one of Obsidian's most useful features for seeing the "big picture" of your knowledge.

Plugin

A small program that extends Obsidian's functionality. Plugins can add new features without requiring you to modify Obsidian itself.

Who Should Use Obsidian?

Obsidian is perfect for:

Students & Researchers: Build a personal knowledge base for your studies. Link research papers, theories, and findings together.
Writers & Academics: Manage citation notes, organize sources, and develop arguments through interconnected notes.
Programmers: Document code, create technical references, and build knowledge bases about technologies you use.
Knowledge Enthusiasts: Create a "digital garden"—a second brain that captures and connects your learning over time.
Project Managers: Organize project planning documents and connect them to related resources.

Obsidian is not ideal for:

Team collaboration (though there are workarounds)
Complex database management (use Notion instead)
Real-time synchronization across devices (that's what Obsidian Sync is for, but it's a paid add-on)

Obsidian's Philosophy

"A generator of ideas" - Obsidian is designed to help you think better by making connections between ideas visible and easy to explore.

The makers of Obsidian believe your notes are too important to trust to cloud companies. They emphasize:

Privacy: Your thoughts remain private by default
Longevity: Plain text Markdown will be readable for decades
Flexibility: Open source plugins and API let you customize everything
Ownership: You own your notes. Full stop.

Ready to Get Started?

Now that you understand what Obsidian is, you're ready to download and install it! In the next module, we'll walk through the installation process step-by-step.

Before moving on: You don't need to have Obsidian installed yet, but you might want to follow along with the next module by installing it at the same time.