Mermaid
Open-source diagrams as code, including fishbone
- Researched profile
- Free plan
- Open source
- Free option
- Free plan
- Pricing
- Free
- Licence
- Open source
- Deployment
- Self-hosted, Cloud
The lean-stack take
It is a general diagramming tool, not a root cause analysis system. A lean team can use its Ishikawa diagram type to draw a fishbone, and its flowcharts to map a process, in plain text kept with other documents.
Best for
Teams that already write documentation in text or Markdown and want fishbone diagrams and flowcharts kept as text.
Watch out for
Mermaid only draws diagrams, so check where your team will record causes, 5 Whys, actions and owners, since it has no problem-solving workflow.
About
About Mermaid
Mermaid is an open-source JavaScript library that turns plain text into diagrams. It is developed in the mermaid-js project on GitHub, and Mermaid Chart publishes a commercial editor alongside it.
Written by lean-stack from Mermaid's public pages. Vendors can replace it with their own description by claiming this profile.
Features
What Mermaid offers
Ishikawa (fishbone) diagrams
Mermaid documents an Ishikawa diagram type for version 11.12.3 and later, which draws cause and effect diagrams from text.
Flowcharts
Flowcharts are part of Mermaid's syntax, so a team can sketch the process steps around a problem.
Text-based diagrams
Diagrams are written as text and rendered by the library. The text can be stored and versioned like any other document.
Open-source project
The code is developed on GitHub under mermaid-js, with public releases and issues. The Ishikawa type was tracked in a public issue.
Regular releases
Mermaid ships numbered releases. The maintainers' blog describes version 11.13.0 as adding two new diagram types.
Use in other tools
Other tools support Mermaid syntax, including draw.io and a Confluence app, so diagrams can be drawn inside tools a team already uses.
Pricing
Mermaid pricing
Checked October 14, 2026
Starting price
Free
- Pricing
- Free
- Free option
- Free plan
How pricing works
The Mermaid library is free and open source; a separate commercial editor is sold by Mermaid Chart.
The Mermaid library is free and open source. Mermaid Chart offers a separate commercial editor; its plans and prices were not confirmed from search results during this check.
See current prices on mermaid.js.orgMermaid doesn't publish a full plan list, so we show what it does publish. Confirm prices with the vendor.
Strengths and limitations
What stands out, and what to watch
Strengths
- Free and open-source library
- Ishikawa diagram type for fishbone analysis
- Flowcharts for mapping the process around a problem
- Diagrams kept as text, so changes are easy to track
- Mermaid syntax is supported in other tools such as draw.io
Limitations
- A diagramming library, not a root cause analysis or CAPA system
- No 5 Whys, action tracking or problem records
- Writing diagram syntax may not suit shop floor teams
- Ishikawa type needs version 11.12.3 or later, so older embeds may not render it
- Commercial editor plans and prices not confirmed from search results
Based on the vendor's published plans and documentation, not a hands-on test.
Fit
Is Mermaid right for your team?
A good fit if…
- Engineers or CI leads who already write docs in Markdown
- You want fishbone diagrams stored in a wiki or code repository
- You need a free way to draw cause and effect diagrams
- You want process flowcharts and fishbones in the same format
Look elsewhere if…
- You need a structured RCA workflow with 5 Whys, actions and owners
- You need CAPA records with approvals and audit trails
- Your team prefers drag-and-drop diagrams over typed syntax
Reviews
What Mermaid users say
We haven't found published reviews of Mermaid on G2 or Capterra yet. Smaller lean tools often have none, so judge it on the facts above and a trial.
Similar tools
Mermaid alternatives
5xWhys.com
Free
Free no-signup browser tools for fishbone diagrams, 5 Whys, Pareto charts, FMEA scoring and 8D reports; data stays local.
EasyRCA
Published pricing
Plant-focused RCA platform with logic trees, fishbones and 5 Whys, plus action tracking and unlimited users per site.
PRIZ Guru
Free plan + paid
Guided engineering problem-solving workspace with cause-and-effect chains, 5 Whys, TRIZ principles and auto-generated reports.
Sologic Causelink
Price on request
Cause-and-effect charting software for building evidence-based RCA investigations and tracking resulting actions.
| Tool | Pricing | Starting price | Free plan or trial | Deployment |
|---|---|---|---|---|
| Mermaid | Free | Not published | Free plan | Self-hosted, Cloud |
| 5xWhys.com | Free | Free (paid workshop kit available) | Free plan | Web (browser, works offline after loading) |
| EasyRCA | Published pricing | $14,975 per year for one plant | Free trial | Web |
| PRIZ Guru | Free plan + paid | Free to start; paid plan prices not published | Free plan | Web |
| Sologic Causelink | Price on request | Quote-based | None listed | Web |
From each vendor's published pricing. Check current prices on their sites.
FAQ
Mermaid: common questions
What is Mermaid?
Can Mermaid draw a fishbone diagram?
Is Mermaid root cause analysis software?
Is Mermaid free?
Can I use Mermaid in other tools?
For the Mermaid team
Claim this profile
Add your own description, screenshots, case studies and customer logos. We check your domain before anything goes live. Claiming is free and does not change our research or the tool's place in any list.
Claim MermaidSources, checked October 14, 2026
- Ishikawa diagram syntax
- Getting started
- GitHub releases
- Ishikawa diagram issue on GitHub
- Mermaid v11.13.0 release post
- Mermaid on Wikipedia
- draw.io Mermaid syntax docs
Listed October 14, 2026.