Usage 

Backend Module 

Go to Web → ERD Generator.

  1. Pick an extension or select tables.
  2. Set depth.
  3. Hit Generate ERD.

You get the Mermaid code and per-table field lists. Download as .md.

CLI 

vendor/bin/typo3 erd:generate --extension=my_ext
vendor/bin/typo3 erd:generate --extension=my_ext --output=docs/erd.md
vendor/bin/typo3 erd:generate tx_myext_domain_model_person tx_myext_domain_model_address
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Options 

Flag What it does Default
-e, --extension Extension key  
-o, --output Write to file instead of stdout  
-d, --depth Relation depth (0, 1, 2, -1=all) 2
-l, --lang Label language de
--include-internal Show uid, pid, hidden, etc. off
--no-core-tables Skip sys_category, sys_file_reference off

Output 

The .md file contains a Mermaid erDiagram block and field tables per entity.

Viewing 

Open the .md in:

  • Obsidian — renders Mermaid natively
  • Markdown Viewer — online viewer
  • GitHub / GitLab — renders Mermaid in Markdown automatically