Mermaid vs nomnoml (2026): which should you pick?
As of Nov 13, 2026, nomnoml grades higher than Mermaid: 2.8 against 2.4 out of 4.0.
Checked Oct 6, 2026 and Nov 13, 2026 · graded Oct 10, 2026 and Nov 13, 2026 by ToolGPA
Mermaid grades higher on features and platforms. nomnoml grades higher on value for money and the free plan. They get the same grade on ease of use.
Price, platforms and features side by side. The table says where each price was read and when.
Mermaid
Text-based diagramming platform with AI and a visual editor
Which one is for you
Pick Mermaid if
- Fits if you already write Mermaid syntax in your docs or Markdown
- Works for diagrams you want versioned and reviewed as text, like code
Look elsewhere if
- Skip it if you want to pay by the month, since paid plans are billed annually only
- Tight if you're staying free, with 3 diagrams on the plan card, a size limit and 15 AI credits
- Pricey if you lean on the AI, with 300 credits a year on Plus and 2,000 on Premium at $20
- Watch out: one page gives the free plan 3 diagrams on the card and 6 in the table, and the trial length isn't stated
- Not for you if you want a desktop or phone app, or free viewer seats below Premium
Pick nomnoml if
- Fits if you want a class or flow diagram out of a few lines of text
- Works for developers who embed diagrams through the library or command line
Look elsewhere if
- Skip it if you want a freehand canvas or sticky-note board
- Watch out: saving relies on browser localStorage, which the author says comes with no guarantees
- Not for you if you need accounts, sharing links or real-time editing, as the web app has none
- Too light for teams: no collaboration of any kind is listed
How we grade them
| 2.4GPAMermaidFair | 2.8GPAnomnomlGood | |
|---|---|---|
| Value for money | CPlus is $10 a user a month against a category middle of $8.33, and it's billed annually only, so you hand over $120 up front with no monthly option. That buys 300 AI credits for the whole year, and free viewer seats wait for Premium at $20. | AFree, open source and available as a library and a command line tool as well as the web app. |
| Free plan and trial | CBasic is free and includes co-editing and external sharing, but the caps arrive fast: 3 diagrams on the plan card, up to 6 in the comparison table on the same page, a limited diagram size and 15 AI credits. The trial of the paid plans has no stated length. | AFree outright, with no sign-up, cap or paid plan. |
| Features | BThe diagramming job, covered: flowcharts, sequence and ER diagrams, Gantt charts and mind maps written in Mermaid syntax and laid out for you, AI drafts from a document or transcript, a visual editor that rewrites the code as you drag, plus slides and live co-editing. | CClass, component and flow diagrams from text, with styling. It does that fully, but it is a smaller job than a whiteboard, with no freehand canvas or sticky notes. |
| Ease of use | CNo rating on record. This is a tool you learn: Mermaid syntax has its own grammar per diagram type, and the AI drafts and click-and-drag editor soften that rather than remove it. Easier if you already write Mermaid in your docs, a curve if you don't. | CNo store rating on record. You learn its text syntax first. |
| Platforms and integrations | BWeb only, with no desktop or phone app. It has plugins for VS Code, JetBrains IDEs, Cursor, Confluence, Jira, Google Docs, Word and PowerPoint, plus an MCP server so Claude or Cursor can generate diagrams. | CWeb only for most people, plus a library and command line. No integrations are listed. |
| Best for | diagrams you write as text, then tidy by hand | UML diagrams drawn from a text syntax |
The GPA is the average of the five grades: an A is 4 points, an F is none. The full reasons are on each tool's page: Mermaid and nomnoml. How we grade
Price against what you get
Mermaid starts at $10 a month for each person and scores 2.7 out of 4 on features, ease of use and platforms. nomnoml has no paid plan and scores 2.0.
Mermaid scores higher, and starts $10 a month higher: the question is whether the extra is worth that to you. Of the other whiteboard and mind map tools on the chart, 11 score higher than Mermaid for less, and none scores higher than nomnoml for less.
Features, ease of use and platforms, averaged
What paid plans start at, a month (each step along is roughly double) →
- The best score at each price
- Has a free plan
- No free plan
Where they differ
- nomnoml is open source, according to its own site.
- Mermaid also covers presentations.
At a glance
| Mermaid | nomnoml | |
|---|---|---|
| Pricing | Free plan | Free |
| Starts at | $10 per user / month, billed annually ($120 a year) | Free |
| Free plan | Basic plan: 3 diagrams (the comparison table on the same page says up to 6) with a limited diagram size, 15 AI credits, one team and project, and co-editing and external sharing. | None |
| Free trial | Free trial of Plus or Premium; the vendor does not state how long it lasts | None listed |
| Web | ||
| Made by | Mermaid Chart | Daniel Kallin |
| Price read from | mermaid.ai | nomnoml.com |
| Checked | Oct 6, 2026 | Nov 13, 2026 |
Worth knowing
Mermaid
- The free Basic plan is listed as 3 diagrams on its plan card and up to 6 in the comparison table, with a limited diagram size and 15 AI credits.
- Paid plans are billed annually only; the vendor's FAQ says monthly plans are not available.
- AI credits are capped at 300 a year on Plus and 2,000 a year on Premium; only Enterprise is listed as unlimited.
- Free viewer seats start at Premium, and SSO, invoicing and a customer success manager are limited to Enterprise.
nomnoml
- It draws diagrams from code only; there is no freehand canvas or sticky-note board.
- Saving relies on browser localStorage, which the author says comes with no guarantees.
- The web app has no accounts, sharing or real-time collaboration.
Key features
Mermaid
- Diagrams from Mermaid code
- Diagrams are written in Mermaid syntax and laid out automatically. Clicking a node jumps to its code and clicking the code finds its shape, so the two stay in step.
- Mermaid AI
- A description, an uploaded document or a pasted transcript becomes a first-draft diagram, and the AI suggests a fitting diagram type. Use is metered in credits below Enterprise.
- Visual Editor
- Nodes, edges, labels, colors and shapes can be changed by clicking and dragging while the code rewrites itself, with node alignment and movable edges for tidying a layout.
- Live co-editing and share links
- Teammates can co-edit a diagram at the same time, and a share link lets other people view it without logging in. Free viewer seats are part of Premium and Enterprise.
- Plugins and MCP server
- Plugins cover VS Code, JetBrains IDEs, Cursor, Windsurf, Confluence, Jira, Google Docs, Word and PowerPoint. An MCP server lets Claude, VS Code and Cursor generate diagrams.
- Presentations
- Existing diagrams become slides written in Markdown. A deck updates when its diagrams change and can be shared through a public link for viewing and comments.
nomnoml
- Text syntax with live preview
- Edit the code on the left and the diagram on the right updates as you type, with keyboard shortcuts borrowed from Sublime Text.
- Several UML shape families
- Built-in classifier types cover classes, abstract classes, packages, components, sockets, actors, use cases, states, choices, databases and tables.
- Styling directives
- Directives such as #direction, #fill, #font and #spacing change layout and appearance, and custom classifier styles can be defined and imported from other files.
- Library and command line
- The nomnoml npm package renders diagrams on a web page or to SVG in Node, and npx nomnoml converts a file from the command line.
- Browser-only storage
- The web app is client-side and keeps your diagram in the browser's localStorage, so it is there on your next visit, though the author gives no guarantee.
Plans
Mermaid
Basic$0
3 diagrams with a limited diagram size, 15 AI credits, and one team and project. Co-editing and external sharing are included.
Plus$10
per user / month, billed annually ($120 a year)
Unlimited diagrams with no size limit and 300 AI credits per year, for individuals who diagram often.
Premium$20
per user / month, billed annually ($240 a year)
Everything in Plus, plus 2,000 AI credits per year, unlimited free viewer seats, and unlimited teams and projects.
EnterpriseCustom
Everything in Premium, plus SSO, custom contracts and invoicing, IP management, user consolidation and a dedicated customer success manager.
nomnoml
Free$0
The whole editor, the npm library and the command-line renderer are free under the MIT license.
Common questions
Which is cheaper, Mermaid or nomnoml?
As of Nov 13, 2026, nomnoml is cheaper to start with: it is free, against $10 a month for each person for Mermaid. Mermaid starts at $10 per user / month, billed annually ($120 a year), and nomnoml is free.
Which has a free plan, Mermaid or nomnoml?
As of Nov 13, 2026, both Mermaid and nomnoml have a free plan.
More comparisons
How this page was made
- The verdict at the top follows a fixed rule. When both tools are in the same category and either is in our top three for it, the verdict follows that ranking: the higher-placed tool is our pick. The top three weigh who each tool suits as well as its grades, so a pick can go against the GPA. Otherwise the page does not pick one and says which grades higher: the higher GPA first; on a tie, the one with a free plan, then the one that starts cheaper in dollars a month, counted the same way for both; if they are still level, what the choice depends on.
- The grades are our own, from each tool’s review or report card. The GPA is their average.
- Prices, plans and platforms come from each tool’s listing. The table above says where each price was read and when.
- The differences and the answers to the questions are worked out from those listings.