diff --git a/docs/API.md b/docs/API.md
index 8f88fc647..77060635b 100644
--- a/docs/API.md
+++ b/docs/API.md
@@ -1,9 +1,10 @@
 
-The REST API provides access for authenticated users to their data inside the Deck app.
+The REST API provides access for authenticated users to their data inside the Deck app. To get a better understand of Decks data models and their relations, please have a look at the  [data structure](structure.md) documentation.
 
 # Prequisited
 
-All requests require a `OCS-APIRequest` HTTP header to be set to `true` and a `Content-Type` of `application/json`. The API is located at https://nextcloud.local/index.php/apps/deck/api/v1.0
+- All requests require a `OCS-APIRequest` HTTP header to be set to `true` and a `Content-Type` of `application/json`.
+- The API is located at https://nextcloud.local/index.php/apps/deck/api/v1.0
 
 ## Naming
 
@@ -225,7 +226,7 @@ Returns an array of board items
 {
     "title": "Board title",
     "color": "ff0000",
-      "archived: false
+    "archived: false
 }
 ```
 
diff --git a/docs/resources/er-diagram.dia b/docs/resources/er-diagram.dia
new file mode 100644
index 000000000..74c8b8ac9
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diff --git a/docs/resources/er-diagram.jpg b/docs/resources/er-diagram.jpg
new file mode 100644
index 000000000..88d0da77b
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diff --git a/docs/structure.md b/docs/structure.md
new file mode 100644
index 000000000..4117dcfba
--- /dev/null
+++ b/docs/structure.md
@@ -0,0 +1,6 @@
+## Database structure
+
+Deck stores most of its data inside of the database. The structure and relationships between entities is documented in the following ER diagram:
+
+![Screenshot](resources/er-diagram.jpg)
+
diff --git a/mkdocs.yml b/mkdocs.yml
index f4cb649ca..62132f05f 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -9,4 +9,6 @@ pages:
     - API documentation:
         - REST API: API.md
         - Nextcloud API: API-Nextcloud.md
+    - Developer documentation:
+        - Data structure: structure.md