{"id":8313,"library":"mermaid-python","title":"Mermaid-Python","description":"mermaid-python is a Python package (version 0.1) for generating diagrams using Mermaid JS. It allows you to define Mermaid diagrams as strings and render them into standalone HTML files. The project has not seen updates since its initial release over three years ago (March 2021), meaning it may not support newer Mermaid JS features or address recent issues. It is effectively abandoned.","status":"abandoned","version":"0.1","language":"en","source_language":"en","source_url":"https://github.com/CaiusDurling/mermaid-python","tags":["diagrams","mermaid","visualization","html","graphing"],"install":[{"cmd":"pip install mermaid-python","lang":"bash","label":"Install stable version"}],"dependencies":[{"reason":"Used for parsing and manipulating HTML generated by Mermaid.","package":"beautifulsoup4","optional":false},{"reason":"Used for templating the HTML output.","package":"jinja2","optional":false},{"reason":"Used internally, likely for handling markdown within diagram definitions (though the core usage is direct Mermaid string).","package":"markdown","optional":false}],"imports":[{"symbol":"Mermaid","correct":"from mermaid import Mermaid"}],"quickstart":{"code":"from mermaid import Mermaid\n\n# Define your Mermaid diagram string\ndiagram_code = \"\"\"\ngraph TD;\n    A[Start] --> B{Process?};\n    B -- Yes --> C[Do Something];\n    C --> D[End];\n    B -- No --> D;\n\"\"\"\n\n# Create a Mermaid object\ngraph = Mermaid(diagram_code)\n\n# Render the diagram to an HTML file\noutput_filename = \"my_mermaid_diagram.html\"\ngraph.to_file(output_filename)\n\nprint(f\"Diagram saved to {output_filename}\")\n# Open 'my_mermaid_diagram.html' in a web browser to view the diagram.","lang":"python","description":"This quickstart demonstrates how to define a Mermaid graph using a string and render it into a standalone HTML file. The `Mermaid` class takes the diagram definition, and `to_file()` saves it. You then open the HTML file in a browser to see the rendered diagram."},"warnings":[{"fix":"Be aware that it may not support recent Mermaid JS features, syntax changes, or security fixes from newer Mermaid JS versions. Consider alternative, more actively maintained libraries, or directly using Mermaid JS with a dedicated CLI or web service.","message":"The mermaid-python project is effectively abandoned and has not been updated since its 0.1 release over three years ago (March 2021).","severity":"gotcha","affected_versions":"0.1"},{"fix":"For direct SVG or PNG image output, you will need to open the generated HTML file in a headless browser (e.g., using Playwright, Selenium, or Puppeteer via a subprocess) and take a screenshot, or integrate with an external Mermaid CLI tool (like `mermaid-cli` or `@mermaid-js/mermaid-cli`).","message":"mermaid-python only renders diagrams to standalone HTML files.","severity":"gotcha","affected_versions":"0.1"},{"fix":"Validate your Mermaid diagram string using the official Mermaid Live Editor (https://mermaid.live/) before passing it to the `Mermaid()` constructor. Check the browser's developer console when opening the HTML file for Mermaid JS specific errors.","message":"If the generated HTML file does not display your diagram, or shows a rendering error, it's almost always due to invalid Mermaid JS syntax in your input string.","severity":"gotcha","affected_versions":"0.1"}],"env_vars":null,"last_verified":"2026-04-16T00:00:00.000Z","next_check":"2026-07-15T00:00:00.000Z","problems":[{"fix":"Ensure you have installed the library correctly: `pip install mermaid-python`. If using virtual environments, activate the correct environment before running your script.","cause":"The 'mermaid-python' library is not installed in your current Python environment, or the environment where you installed it is not active.","error":"ModuleNotFoundError: No module named 'mermaid'"},{"fix":"Verify your Mermaid diagram string for any syntax errors using the Mermaid Live Editor (https://mermaid.live/). Also, open the generated HTML file in a browser and check its developer console for JavaScript errors related to Mermaid.","cause":"This usually indicates that the Mermaid JavaScript failed to render the diagram, most commonly due to invalid or malformed Mermaid diagram syntax in the input string.","error":"The generated HTML file is blank or contains only the Mermaid source code, not the diagram."},{"fix":"Ensure that the directory where you intend to save the HTML file exists. You can create it programmatically using `os.makedirs(os.path.dirname(output_filename), exist_ok=True)` before calling `to_file()`.","cause":"The path provided to `graph.to_file()` includes directories that do not exist.","error":"FileNotFoundError: [Errno 2] No such file or directory: 'non_existent_path/my_diagram.html'"}]}