1Paste the broken Mermaid code into the editor and describe the repair goal.
2Ask for a minimal syntax fix first when the diagram structure is already correct.
3Preview the repaired source before asking for readability improvements.
4Compare the fixed diagram with the original intent so the AI does not silently redesign the flow.
5Export only after the repaired Mermaid code remains understandable.

Common use cases

Mermaid syntax repairAI-generated diagram cleanupREADME diagram fixesSequence diagram repairLabel readability improvements

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FAQ

Which AI provider is used?

The server calls DeepSeek directly and uses a local template fallback when DeepSeek is unavailable or not configured.

Are API keys exposed to the browser?

No. API keys are read only on the server through environment variables.

Should I ask for a redesign or a syntax fix?

Ask for a minimal syntax fix first. Once the diagram renders, you can separately ask for shorter labels, subgraphs, or layout improvements.

Can AI change the meaning of a Mermaid diagram while fixing it?

Yes. Always compare the repaired diagram with the original source and check whether participants, edges, states, and branches still mean the same thing.

Mermaid AI Fixer repairs broken Mermaid syntax and helps make generated diagrams readable without losing the original intent.

Use it when ChatGPT, another AI tool, or a copied README snippet returns Mermaid that fails to render because of labels, arrows, missing headers, or mixed syntax.

The safest workflow is minimal fix, preview, then optional readability cleanup. The server calls DeepSeek directly and uses a local template fallback when DeepSeek is unavailable.

Demo: repair a broken Mermaid flowchart

AI-generated Mermaid often fails because labels contain reserved punctuation, arrows are mixed, or subgraph syntax is incomplete. A fixer should return valid code and keep the original intent.

Preserve node meaning while simplifying labels.
Quote labels that include slashes, colons, or parentheses.
Render the fixed diagram immediately to confirm the repair.

flowchart LR
  A[User submits /checkout] --> B{Payment OK?}
  B -- yes --> C[Create order]
  B -- no --> D[Show retry]

Debugging: fix syntax before improving style

The repair loop should solve rendering first. Once the diagram renders, then improve grouping, labels, and layout; otherwise the model may hide the original syntax error behind a redesign.

Ask for the smallest valid patch when the structure is already good.
Ask for readability improvements only after render errors are gone.
Keep a copy of the broken input for regression testing.

Broken -> minimal fixed Mermaid -> rendered preview -> optional refactor

Repair checklist: preserve meaning while fixing syntax

A Mermaid fixer should not turn an error into a different diagram. Keep the semantic pieces stable, then make the source valid and readable.

Check that every original participant, state, or node still exists unless you asked to remove it.
Verify edge direction and branch labels after the repair.
Keep a copy of the broken input so you can compare before and after.

Original intent: User submits checkout -> API validates -> Payment authorizes -> Order created
Repair goal: valid Mermaid only, no new services

Review checklist for Mermaid AI Fixer

Use Mermaid AI Fixer when you need to inspect source content visually before it becomes documentation, a pull request note, an incident write-up, or a handoff artifact. Fix broken Mermaid syntax and improve diagram readability with AI.

Before exporting, check that labels are readable, relationships match the source, generated examples do not contain private data, and the preview still makes sense after you edit the input.

Limits and troubleshooting

If the preview fails, reduce the input to the smallest complete example, confirm the format syntax, and then add sections back one at a time. Many rendering failures come from partial files, indentation mistakes, missing diagram headers, or copied snippets that depend on hidden context.

Treat the preview as a review surface rather than a source of truth. Generated diagrams, converted files, dashboards, and rule examples should be checked before they are used in production documentation or operations.

Example inputs to test

Broken flow: Fix the syntax and keep the same flow.
Broken sequence: Fix this sequence diagram and keep the participants.
Broken state: Fix this state diagram.

Tool maturity

AI beta

AI-assisted beta

This tool can generate editable source with an AI provider. Review the output, render it locally, and adjust details before publishing.

The maturity label is not a quality score. It tells visitors whether the tool is best for stable export, deeper debugging, quick parsing, or AI-assisted generation.