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Free Text to Diagram (Flowchart, Sequence, ERD)
A free, in-browser text to diagram editor powered by Mermaid, the open-source JavaScript diagramming and charting tool that turns Markdown-inspired text definitions into rendered diagrams. Write a few lines of simple, readable syntax and watch the diagram render instantly in the live preview. Start from prefilled templates for flowcharts, sequence diagrams, class diagrams, entity relationship (ER) diagrams, Gantt charts, state machines, and pie charts, then edit the code to match your system. The preview debounces as you type and surfaces friendly parser errors when the syntax is incomplete, so you never stare at a blank screen. When you are happy, copy the SVG markup to your clipboard or download a vector .svg for docs, slides, README files, and wikis. Everything runs locally in your browser with no server calls, so your architecture, schemas, and data never leave your device.
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Diagrams as code, rendered instantly in your browser
Drawing diagrams by hand is slow, and keeping them in sync with a fast moving system is harder. Mermaid was built to solve exactly this: it is a diagramming and charting tool that uses Markdown-inspired text definitions and a renderer to create and modify diagrams, with the explicit goal of helping documentation catch up with development. This tool puts that workflow in your browser. You describe the diagram in a few lines of Mermaid text, and the picture is generated for you. Change one line and the diagram updates instantly in the live preview, so you spend your time on the logic of the flow rather than nudging boxes and arrows into alignment.
Because the diagram is just text, it fits naturally into a developer workflow. This is the diagram-as-code approach: you keep the source in Git, diff it in pull requests, paste it between documents, and regenerate the visual any time. It is the same Mermaid syntax that GitHub, GitLab, Notion, and Obsidian render natively, so anything you build here drops straight into those platforms. When you need a portable image, copy the SVG markup or download a vector .svg that stays sharp at any resolution.
Built for software architecture and documentation
The prefilled templates cover the diagrams engineers reach for most: flowcharts for process and decision logic, sequence diagrams for request and message flows, class diagrams for object models, entity relationship diagrams for database schemas, Gantt charts for project timelines, and state diagrams for lifecycle modeling. Each template is valid, working Mermaid code you can edit immediately, and the editor accepts any other Mermaid diagram type, from git graphs to user journey maps to C4 context diagrams.
Mermaid describes the problem it tackles as doc-rot, where diagramming and documentation cost precious developer time and get outdated quickly. Keeping diagrams as text fixes that: the source lives beside the code, updates in the same pull request, and never drifts out of sync. This tool is a fast companion for writing technical docs, READMEs, design proposals, and onboarding guides. Sketch an idea, validate the syntax with the inline parser feedback, and export a clean SVG to embed wherever your team reads documentation.
Private by design, open source under the hood
Everything happens client side. Your diagram text is never uploaded, stored, or logged, which makes the tool safe for documenting internal architecture and private schemas. There is no signup, no account, and no API key. Mermaid runs in strict security mode, so any scripts or event handlers embedded in diagram text are stripped from the rendered SVG output. If you want proof, open the Network tab in your DevTools while you edit and watch: no request ever carries your diagram.
The rendering engine is Mermaid, a mature open-source project released under the MIT license and maintained in the open at github.com/mermaid-js/mermaid. After the page loads, the tool continues to work on slow or restricted networks because rendering is local. Open it, pick a template, and start turning text into clear diagrams in seconds.
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Who writes diagrams as text, and when
Backend engineers sketch a sequence diagram while designing an API before writing any code, since it is faster to reorder a few text lines than to redraw arrows on a canvas. Technical writers keep an ER diagram next to a database migration so schema docs never fall out of sync with the actual tables, and engineering managers build a Gantt chart from a few lines of text to share a rollout timeline without opening a project-management tool.
It also gets used in onboarding docs, where a state diagram or flowchart embedded directly in a README explains a system's lifecycle far faster than a paragraph of prose, and in incident postmortems, where a quick sequence diagram of what actually happened is often the clearest way to communicate a root cause.
How this compares to Lucidchart, draw.io, and Miro
Lucidchart and Miro are built for freeform, drag-and-drop diagramming and collaboration, and both charge for real usage: Lucidchart's individual plans start around 9 dollars a month and team plans run higher, while Miro's paid tiers start around 8 to 16 dollars a month per user. draw.io (now diagrams.net) is free and open source but is still a manual canvas tool, every box and connector is placed and dragged by hand.
This tool trades canvas freedom for speed and version control: you describe a diagram in a few lines of text and it renders instantly, which is dramatically faster than manual layout for structured diagrams like sequence flows, ER diagrams, and flowcharts, and the source can live in Git and be reviewed like code. For a highly custom, artistic, or non-standard layout, a drag-and-drop tool still wins, but for the diagrams engineering teams draw most often, code-based generation is usually faster end to end.
Tips for writing clean Mermaid syntax
Almost every parser error traces back to one of a few things: a missing diagram-type declaration on the first line (flowchart TD, sequenceDiagram, classDiagram), an arrow written with the wrong number of dashes, or a label containing a character like a colon or parenthesis that needs to be wrapped in quotes. Start from the closest matching template rather than a blank editor, since a working example is much easier to modify correctly than to write from scratch.
For larger diagrams, build them incrementally: get three or four nodes rendering correctly, then add the rest in small batches so a syntax error is easy to isolate to the last few lines you typed. If a flowchart looks cramped or oddly directed, changing the direction keyword (TD for top-down, LR for left-right) is often a bigger visual improvement than manually repositioning individual nodes.
How It Works
Pick a template (flowchart, sequence, class, ERD, Gantt, state, or pie) to prefill working Mermaid code, or paste your own Markdown-inspired diagram text.
Edit the text on the left and watch Mermaid render the diagram live on the right, with clear parser errors inline if the syntax is incomplete.
Copy the rendered SVG markup to your clipboard or download a vector .svg file to drop into docs, slides, READMEs, and wikis.
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Key Features
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Use Cases
Limitations
- You write Mermaid text syntax, so there is no freeform drag-and-drop canvas like Figma or draw.io. The tradeoff is diagrams that live as readable, diffable text.
- Very large or deeply nested diagrams can take longer to lay out and may need manual tuning of direction, subgraphs, or spacing.
- Export is SVG only. To get a PNG or PDF, open the downloaded SVG in a vector editor or run it through a converter.
- Some advanced or experimental Mermaid diagram types are version dependent and may render slightly differently across Mermaid releases.
Frequently Asked Questions
Is this diagram from text tool free?
Yes, it is completely free with no signup, no account, and no usage limits. It is built on Mermaid, an open-source diagramming and charting tool released under the MIT license, and it runs entirely in your browser. There is no paid tier and no API key to obtain. You can generate as many flowcharts, sequence diagrams, ER diagrams, and Gantt charts as you like.
Is my diagram text sent to a server?
No. The entire tool runs client side in your browser. Your Mermaid text is parsed and rendered locally and is never uploaded, stored, or logged. That makes it safe for documenting internal architecture, private database schemas, and other sensitive systems. You can confirm this by opening the Network tab in your browser DevTools while you type: you will see no outbound request carrying your diagram after the initial page load.
What is Mermaid and why describe diagrams as text?
Mermaid is a popular open-source JavaScript tool that turns Markdown-inspired text definitions into rendered diagrams. Instead of dragging shapes around a canvas, you write a few readable lines and Mermaid generates the picture. Its stated goal is to help documentation catch up with development and avoid the doc-rot where diagrams go stale. Because the source is plain text, it is easy to version control in Git, review in pull requests, copy between documents, and edit quickly without a mouse.
Do I need to install anything?
No installation, extension, or download is required. The tool loads in any modern browser, including Chrome, Edge, Firefox, and Safari, on both desktop and mobile. Mermaid runs as client-side JavaScript on the page, so you just open it and start typing. This is the same rendering engine that platforms like GitHub, GitLab, Notion, and Obsidian use to draw Mermaid diagrams from text.
Which diagram types can I create?
The editor supports the full Mermaid 11 syntax. The template dropdown gives you working starting points for flowcharts, sequence diagrams, class diagrams, entity relationship (ER) diagrams, Gantt charts, state diagrams, and pie charts. You can also paste any valid Mermaid code, including git graphs, user journey maps, and C4 diagrams, and it will render immediately.
Why does the preview show a syntax error sometimes?
The live preview validates your Mermaid code before drawing it. If the syntax is incomplete or invalid, the tool shows the Mermaid parser error message instead of a broken diagram. This is normal while you are mid-edit. Once the syntax is valid again, the diagram re-renders automatically. Check for typos in arrows, missing brackets, or an incorrect diagram declaration on the first line, such as 'flowchart TD' or 'sequenceDiagram'.
Does it work offline and on mobile?
After the page loads, rendering happens entirely on your device, so the tool keeps working on slow or restricted networks. It runs in any modern browser on both desktop and mobile. You can paste Mermaid code from a GitHub README, Notion, or Obsidian to preview it, tweak it, and export an updated SVG without anything leaving your device.
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