diff --git a/packages/core/src/Extension.ts b/packages/core/src/Extension.ts
index fa9cf3e8..a3d9e50c 100644
--- a/packages/core/src/Extension.ts
+++ b/packages/core/src/Extension.ts
@@ -8,6 +8,8 @@ import { GlobalAttributes, RawCommands, ExtensionConfig } from './types'
 
 declare module '@tiptap/core' {
   interface ExtensionConfig<Options = any> {
+    [key: string]: any;
+
     /**
      * Name
      */
diff --git a/packages/core/src/Mark.ts b/packages/core/src/Mark.ts
index 42d7ed7c..4f610237 100644
--- a/packages/core/src/Mark.ts
+++ b/packages/core/src/Mark.ts
@@ -18,6 +18,8 @@ import { Editor } from './Editor'
 
 declare module '@tiptap/core' {
   export interface MarkConfig<Options = any> {
+    [key: string]: any;
+
     /**
      * Name
      */
diff --git a/packages/core/src/Node.ts b/packages/core/src/Node.ts
index bb1326ff..5ac448b7 100644
--- a/packages/core/src/Node.ts
+++ b/packages/core/src/Node.ts
@@ -19,6 +19,8 @@ import { Editor } from './Editor'
 
 declare module '@tiptap/core' {
   interface NodeConfig<Options = any> {
+    [key: string]: any;
+
     /**
      * Name
      */