📪1.1 Introduction to Mermaid
Mermaid for Beginners
What is Mermaid?
Explain Mermaid as a text-based diagramming tool.
Compare it with traditional drawing tools.
Benefits: version control, easy to learn, works in Markdown.
1. Explain Mermaid as a Text-Based Diagramming Tool
In modern software development and technical writing, diagrams play a crucial role in explaining how systems work, how processes flow, and how different components interact. Traditionally, creating diagrams meant using separate design tools like Visio, Lucidchart, or draw.io. While these tools are powerful, they rely on manual drag-and-drop editing, which can be time-consuming to maintain — especially when systems evolve or documentation lives alongside source code.
Mermaid changes this by treating diagrams like code. Instead of drawing boxes and arrows by hand, you write a simple, structured markup language using plain text. This text describes nodes, connections, and relationships in a diagram. When processed by a tool that supports Mermaid — like GitBook, GitHub, Notion, or many Markdown editors — your plain text is automatically rendered into a clean, shareable diagram.
This approach offers several key advantages:
Version Control: Because your diagrams are plain text, they can be stored, tracked, and reviewed in the same version control system (like Git) as your source code. You can see who changed what, when, and why.
Consistency: Text-based syntax ensures your diagrams are always clear and reproducible. No more accidentally misaligned shapes or disconnected arrows.
Efficiency: Updating a diagram is as easy as editing a line of text. There’s no need to open a separate app or redraw complex flows from scratch.
Portability: You can embed Mermaid diagrams directly in Markdown files, project wikis, or static site generators, making your documentation interactive and up-to-date wherever it lives.
Mermaid is especially popular with developers, technical writers, and teams who embrace Documentation as Code. It’s widely used to produce flowcharts, sequence diagrams, architecture overviews, entity-relationship diagrams, class diagrams, and even Gantt charts — all with just a few lines of easy-to-read text.
In essence, Mermaid bridges the gap between technical documentation and visual clarity, enabling teams to build and maintain diagrams as an integral part of the development process — without leaving their favorite text editor.
2. Compare It with Traditional Drawing Tools
Before tools like Mermaid, creating diagrams usually meant using visual drawing tools such as Microsoft Visio, Lucidchart, draw.io, or similar applications. These tools offer user-friendly drag-and-drop interfaces that let you design flowcharts, architecture diagrams, mind maps, and other visuals by manually arranging shapes, lines, and labels on a canvas.
While traditional drawing tools are powerful and flexible, they come with some challenges:
Manual Effort: Every box, arrow, or label must be dragged, dropped, positioned, and adjusted by hand. Making even a small change, like adding a new node or reordering steps, can require rearranging multiple elements.
Harder to Maintain: As your system or process evolves, diagrams created visually can quickly become outdated. Updating them often means opening a separate file, finding the right diagram, and reworking the layout.
Poor Version Control: Diagram files made in traditional tools are usually binary (like
.vsdx) or proprietary formats. This makes it difficult to track changes line by line in a version control system like Git. If you and your team make edits, merging those changes is rarely straightforward.Limited Collaboration: Sharing a visual diagram often means exporting it as an image or PDF. If someone else needs to edit it, they usually need the same software installed — and any manual edits must be done separately.
Mermaid takes a different approach: Instead of manipulating shapes visually, you write text instructions describing the structure of your diagram. For example, instead of dragging an arrow from “User” to “Server,” you write:
This approach makes diagrams:
Easier to maintain: You can quickly add, remove, or rearrange elements by editing lines of text.
Fully version-controlled: Because Mermaid diagrams are plain text, they work perfectly with Git. You can see exactly what changed, when, and why.
Collaborative: Anyone on your team can suggest edits, review changes, and keep diagrams aligned with the actual system design.
Consistent with Documentation as Code: Mermaid fits naturally into Markdown files, wikis, README files, and developer docs — keeping visuals close to the source code and the rest of your technical documentation.
In summary, traditional drawing tools are great for manual, design-heavy diagrams. But when you need maintainable, reusable, and always up-to-date diagrams — especially in a software project — Mermaid’s text-based approach saves time, ensures consistency, and makes collaboration much smoother.
3. Benefits: Version Control, Easy to Learn, Works in Markdown
One of the main reasons developers and technical writers love Mermaid is that it brings practical, real-world advantages over traditional diagramming methods. Let’s break down three of the biggest benefits:
✅ 1. Version Control Friendly
Because Mermaid diagrams are written as plain text, they fit naturally into any version control system like Git. This means your diagrams live right alongside your source code and documentation.
When you update a diagram, you don’t just overwrite a file — you make a clear, trackable change. You can see exactly which lines were added or removed, when, and by whom. If you ever need to revert or compare versions, it’s as simple as using standard Git commands.
In contrast, traditional diagram tools often save files in binary formats, which don’t play well with version control. You can’t easily see what changed inside a .vsdx or .drawio file — you only see that the file size changed, not how the diagram evolved.
✅ 2. Easy to Learn
Mermaid’s syntax is intentionally simple and human-readable. Even if you’ve never used it before, you can understand a diagram just by reading the text:
Most people learn the basics — nodes, arrows, labels — in just a few minutes. Once you know the key building blocks, you can create flowcharts, sequence diagrams, and more without needing advanced design skills or specialized software.
Plus, since Mermaid is used directly in text editors or online docs, you can edit diagrams anytime, without switching tools.
✅ 3. Works Seamlessly in Markdown
Mermaid was designed to work inside Markdown, which is the backbone of modern documentation — from README files to GitBook pages, wikis, and note-taking apps like Obsidian.
This means you don’t need to manage separate image files or embed static screenshots. Instead, your diagram lives inside your Markdown file as a code block. Tools like GitHub, GitLab, and GitBook render it automatically.
If your documentation changes — for example, you add a new feature or change a process — updating your diagram is as simple as editing the text block right where you wrote your instructions. No exporting, no image uploading, no extra files to manage.
In short: ✅ Version control keeps your diagrams transparent and traceable. ✅ Easy syntax makes diagrams simple to learn and update. ✅ Markdown-friendly design keeps visuals close to the content, always in sync with the rest of your documentation.
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