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, a full Markdown doc, and per-table field lists. Copy or download as .md.

CLI 

vendor/bin/typo3 erd:generate --extension=my_ext
vendor/bin/typo3 erd:generate --extension=my_ext --output=docs/erd.md --check-db
vendor/bin/typo3 erd:generate --list-extensions
vendor/bin/typo3 erd:generate --list-tables
vendor/bin/typo3 erd:generate tx_myext_domain_model_person tx_myext_domain_model_address
Copied!

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
--check-db Show field population % off
--include-empty Keep 0% fields (needs --check-db) off
--include-internal Show uid, pid, hidden, etc. off
--no-core-tables Skip sys_category, sys_file_reference off
--list-extensions List extensions and exit  
--list-tables List tables and exit  

Output 

The .md file contains a Mermaid erDiagram block, field tables per entity, a relations overview, and cardinality labels (0:1, 1:n, n:m).

Viewing 

Open the .md in:

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