ChartAI vs Mermaid Chart

Two fact sheets from our own research, side by side — pricing, platforms, API access and status re-checked by us rather than quoted from the vendors.

The short answer

Entry price: ChartAI from $5 once, Mermaid Chart from $80/yr — different billing units, so no direct winner
Free plan: Only Mermaid Chart (ChartAI has paid plans only)
Higher Trust score: Mermaid Chart — 92 vs 74 for ChartAI
Best fit: ChartAI: Students and occasional users who need a handful of diagrams without a subscription · Mermaid Chart: developers already writing Mermaid syntax who want a hosted editor
Platforms: ChartAI: Web · Mermaid Chart: Web, VS Code extension

From our own records as of each tool's last check. Anything we have not confirmed is left out rather than guessed. How we verify

ChartAIChat interface that turns a description into a Mermaid diagram, sold as credits where one credit is one diagram.

Mermaid ChartTurns text, code, or prompts into flowcharts, sequence diagrams, and Gantt charts, from the Mermaid.js team.

Side by side

Fact	ChartAI	Mermaid Chart
Category	Diagramming & Whiteboards	Diagramming & Whiteboards
Pricing model	Paid	Freemium
Starts at	$5 once	$80/yr
Trust score	74 / 100	92 / 100
Platforms	Web	Web, VS Code extension
Company	Neural Canvas Inc.	Mermaid Chart
Launched	—	2022
Last verified	Oct 15, 2026	Oct 15, 2026

What our research says

ChartAI

The pricing is the clearest thing about it: $5 once for 25 diagrams that never expire, or $24 a month for unlimited use, with Mermaid output you can keep and edit elsewhere. Against that, the app is a lightly reskinned chat client with ad-network tags on the page, and the vendor's country and support arrangements are barely documented.

Pros

One credit equals one diagram, and one-time credits never expire
Pro removes the per-diagram meter for $24 a month
Renders Mermaid, so output can be exported and edited as text
PNG and SVG export with in-place edits and colour themes

Cons

The interface is a generic chat client shell with little diagram-specific tooling
The page carries ad-network tags, which is unusual for a paid product
No company address or country disclosed - only an Inc. name in the footer
No public API, collaboration features or version history found

Mermaid Chart

Being built by the Mermaid.js maintainers themselves is the real edge here: diagrams-as-code that developers already write in markdown get a proper collaborative editor and AI-assisted generation on top, instead of a third party reverse-engineering the syntax. The free tier's five-diagram cap is tight, and the vendor's recent rebrand from mermaidchart.com to mermaid.ai makes some third-party pricing pages describing it look slightly out of date.

Pros

built and maintained by the original Mermaid.js open-source team
generates diagrams from plain text or AI prompts, or direct syntax editing
real-time multi-user collaboration
integrations with VS Code, Confluence, and similar developer tools

Cons

free plan is capped at five diagrams
recent domain move from mermaidchart.com to mermaid.ai has left some third-party listings referencing the old pricing page
per-user annual billing can add up for larger teams versus flat team pricing

Which one fits

Choose ChartAI if you need

Students and occasional users who need a handful of diagrams without a subscription
Anyone who wants Mermaid source they can paste into docs or a README
People who present weekly and want unlimited flowcharts and sequence diagrams

Choose Mermaid Chart if you need

developers already writing Mermaid syntax who want a hosted editor
teams wanting diagrams generated from text or code with light AI assistance