Best Mermaid Diagram Tools in 2026: Miro and 9 Alternatives

Mermaid is a text-based diagram language: you write a few lines describing the boxes and arrows, and a renderer draws a flowchart, sequence diagram, class diagram, Gantt chart or another supported type. A diagram that lives as text can sit in a document, change in a pull request and be fixed in seconds, instead of being a screenshot nobody can edit.

The catch is that plain text is hard to workshop, and not every app draws it. I checked each tool's own documentation or help page in November 2026 and read six of the pages that rank for this search. Most are written by a vendor who ranks their own product first, so I say where Miro is featured here and what each tool cannot do.

What does Mermaid look like?

Six lines of text describe a sign-up flow, and a renderer turns them into the diagram below.

flowchart LR
  A[Visitor] --> B{Has account?}
  B -- Yes --> C[Dashboard]
  B -- No --> D[Sign up]
  D --> E[Verify email]
  E --> C

Change a word in the text and the diagram redraws. That is the whole appeal, and it is why the tools below differ mainly in what happens after the diagram is drawn.

Best Mermaid tools compared

1. Miro: best for editing Mermaid together

Miro renders Mermaid code as real, editable shapes on a shared board, according to its own Mermaid page. Flowchart, sequence, class and ER diagrams get native shapes with visual editing, and the code updates to match. Miro says you can import Mermaid code and export diagrams as Mermaid syntax, that AI agents such as Claude Code and Cursor can read and write diagrams through MCP, and that Mermaid code can run to 30,000 lines. Teams get real-time or asynchronous editing, comments and version history, and someone drafts the flow in text while everyone else moves boxes and runs the workshop.

The trade-offs are worth knowing. Miro says migrating from other tools is not automated yet, other diagram types such as Gantt are mentioned without visual editing, and its help centre labels the feature beta in one language version, so check coverage for your diagram type. The Free plan keeps three boards editable, and prices are listed in US dollars, so budget for the exchange rate if you pay from India. If your team already runs retros and planning on boards, see our guides to team collaboration tools and AI brainstorming tools.

Pick it if the diagram needs comments, review and several editors. Skip it if you want diagrams only as text in a repository.

2. Mermaid Chart: best for people who write Mermaid daily

Mermaid Chart, now at mermaid.ai, calls itself a collaborative diagramming platform where you create diagrams with AI, code or clicks. You write Mermaid syntax and watch the diagram lay itself out, generate one from a description or transcript, and co-edit live with a share link that needs no login. It lists integrations with GitHub Copilot, Confluence, Jira, Google Docs, VS Code, JetBrains and Cursor. A free Basic plan exists, and paid plans add collaboration tools, more AI credits and file uploads. The page I checked showed no prices.

Pick it if Mermaid is your main diagram language. Skip it if you need a general whiteboard around the diagrams.

3. Mermaid Live Editor: best for quick drafts

The Mermaid Live Editor at mermaid.live is the lightest way to start. You edit Mermaid text, see the diagram update in real time, save the result as an SVG and share a link to a viewer or an editable copy. It belongs to the mermaid-js project, and the repository lists an MIT licence. It is a drafting pad, not a team workspace, which is the main difference from Mermaid Chart. Use it when you want a fast, open-source sketch, and move on when several people need to edit and comment.

4. draw.io: best for polishing a diagram by hand

In draw.io you can insert Mermaid text under Arrange, Insert, Mermaid, and it converts the source into native draw.io shapes that you can restyle, move and resize. The trade-off is that layout changes are lost if you regenerate from the source, so treat the import as a starting point. The page I checked did not state pricing or licence terms.

Pick it if you want full control over how the diagram looks. Skip it if you want the text to stay the source of truth.

5. Lucidchart: best if your team already uses Lucid

Lucidchart has a Diagram as code menu: choose a new Mermaid diagram, enter the code and click Generate. Lucid says it supports eight diagram types, including flowchart, sequence, class, state, C4, Gantt and entity relationship diagrams. Exporting a Lucid diagram back to Mermaid is still a community request. Our mind mapping tools roundup covers Lucid and its neighbours.

Pick it if your diagrams already live in Lucid. Skip it if you need two-way Mermaid editing.

6. GitHub: best for docs that live next to code

GitHub renders Mermaid when you put it in a fenced code block tagged mermaid. According to its docs, diagram rendering works in issues, discussions, pull requests, wikis and Markdown files. The architecture diagram sits in the README and gets reviewed like any other change. The fence looks like this:

```mermaid
flowchart LR
  A[Visitor] --> B[Sign up]
```

The limit is that it only displays: to change a box you edit the text.

7. GitLab: the same idea, with one self-managed catch

GitLab renders Mermaid from fenced code blocks tagged mermaid across GitLab Flavored Markdown: comments, issues, epics, merge requests, milestones, snippets, wiki pages, repository Markdown files and releases. Its docs say it supports Mermaid version 12. One catch for self-managed installs: a Cross-Origin-Resource-Policy header set to same-site or same-origin makes Mermaid diagrams fail silently, and the docs say to use cross-origin instead.

Pick it if your code and wiki are on GitLab. Skip it if you run self-managed GitLab and cannot change that header.

8. VS Code: best for previewing while you write

VS Code's built-in Markdown preview renders Mermaid in fenced code blocks, with no extension needed. You can pan and zoom larger diagrams and copy a diagram's Mermaid source from its context menu. It runs on your own machine, which matters if the diagram describes something you would rather not paste into a browser tool. It is a preview, so non-developers cannot edit what you build there.

9. Obsidian: best for personal notes

Obsidian supports Mermaid with a code block tagged mermaid, and its help page points to the Mermaid docs and the Live Editor for building diagrams before you add them to a note. It suits founders who keep planning notes and system sketches in one place, though the diagram stays inside your vault unless you export it.

10. Mermaid CLI: best for exporting diagrams in a build

Mermaid CLI, run as mmdc, takes a Mermaid definition file and generates an SVG, PNG or PDF. It can also process a Markdown file, find the Mermaid code blocks and link the generated SVGs in the output. It needs Node.js, so it is a developer tool, and the basic command is mmdc -i input.mmd -o output.svg. Reach for it when a documentation build must produce image files, and skip it for an occasional export.

When Mermaid is not enough: D2 and PlantUML

Two text-to-diagram languages come up in the same searches. D2 calls itself a modern language that turns text to diagrams, with a sketch mode, animations, a local CLI with watch mode and export to SVG, PNG, PDF, PPTX, GIF and ASCII. PlantUML describes itself as an open-source tool that draws UML diagrams from textual descriptions, covers sequence, class, state, component and many non-UML types, and uses Graphviz for layout by default.

Both are worth a look if Mermaid's layout or diagram types fall short, and Miro says it supports PlantUML alongside Mermaid. Other editors that show up for this search, such as Visual Paradigm's VPasCode, HackMD and Kroki, are real options, but I left them out because their pages are vendor claims I could not compare like for like.

Which Mermaid tool should you pick?

• Teams who workshop diagrams together: Miro, so a Mermaid draft becomes a board everyone can edit.
• People who write Mermaid every day: Mermaid Chart, for its editor and integrations.
• Engineers documenting systems: GitHub or GitLab, with the diagram in the repository, and VS Code to preview it.
• One-off drafts: the Mermaid Live Editor.
• A polished visual: draw.io, after importing.

Keep the text as the source of truth, and use a board to explain it to other people.

I would draft in Mermaid, then move to Miro when the conversation begins. The open question is round-tripping: Miro says it exports Mermaid, but I have not tested how cleanly a heavily edited board comes back, and Lucid's own community lists export as an open request. For the wider stack around that, our guide to project management tools for startups is a good next read.

FAQs

Is there a free Mermaid editor?

Yes. The Mermaid Live Editor at mermaid.live is an open-source browser editor, Mermaid Chart has a free Basic plan, and Miro says Mermaid support is free on every plan.

What is the difference between Mermaid Live Editor and Mermaid Chart?

The Live Editor is an open-source drafting pad for editing, previewing and sharing diagrams. Mermaid Chart is a collaborative platform with AI generation, live co-editing and integrations, with paid plans.

Can Miro import and export Mermaid?

Miro says you can paste Mermaid code to create editable shapes and export diagrams as Mermaid syntax. Flowchart, sequence, class and ER diagrams get native shapes, and migrating from other tools is not automated yet.