# Import diagram source from a file

If the diagram already exists as a file, import it rather than copying and pasting through a text editor that may mangle the whitespace.

Several source formats are accepted, and the language is detected from the file rather than from whatever was selected.

![Screenshot 2026-09-07 at 10.03.34.png](https://help.gocapable.com/images/acbf8d30-1eef-492c-875c-41d993e691e5.webp)

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## What this is for

* Diagrams that already live in a repository.
* Source somebody has sent you as a file.
* Bulk-importing documentation from elsewhere.

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## How it works

| **Action**         | **How**                                                                   |
| ------------------ | ------------------------------------------------------------------------- |
| Supported files    | .mmd, .puml, .dot, .d2, .txt and .md                                      |
| Import             | The import option in the editor toolbar.                                  |
| Language detection | Taken from the file, so a .puml arrives as PlantUML.                      |
| Markdown files     | Source is taken from the file's contents; check the result before saving. |

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## A few things that catch people out

* Importing replaces the current source. Copy anything you want to keep first.
* Whitespace matters in several languages. Importing preserves it; pasting sometimes does not.
* The full extension list is in [Reference](https://help.gocapable.com/diagrams/reference.html).

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## Related

[Generate diagram code with AIA draft, written into the code pane.](https://help.gocapable.com/diagrams/generate-diagram-code-with-ai.html)

[Write Mermaid in the text editorA worked run through, start to finish.](https://help.gocapable.com/diagrams/write-mermaid-in-the-text-editor.html)

[Text editorBack to the editor overview.](https://help.gocapable.com/diagrams/text-editor.html)

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_The source is right there. Read it._