diff --git a/src/model/schema.js b/src/model/schema.js
index f1fdc4ad5..cb990057d 100644
--- a/src/model/schema.js
+++ b/src/model/schema.js
@@ -39,6 +39,14 @@ export default class Schema {
 	constructor() {
 		this._sourceDefinitions = {};
 
+		/**
+		 * A map containing attribute's properties.
+		 *
+		 * @private
+		 * @member {Map.<String,String>}
+		 */
+		this._attributeProperties = {};
+
 		this.decorate( 'checkChild' );
 		this.decorate( 'checkAttribute' );
 
@@ -140,19 +148,6 @@ export default class Schema {
 		this._clearCache();
 	}
 
-	/**
-	 * Returns all registered items.
-	 *
-	 * @returns {Object.<String,module:engine/model/schema~SchemaCompiledItemDefinition>}
-	 */
-	getDefinitions() {
-		if ( !this._compiledDefinitions ) {
-			this._compile();
-		}
-
-		return this._compiledDefinitions;
-	}
-
 	/**
 	 * Returns a definition of the given item or `undefined` if item is not registered.
 	 *
@@ -475,6 +470,70 @@ export default class Schema {
 		}, { priority: 'high' } );
 	}
 
+	/**
+	 * Registers custom properties to a given attribute.
+	 *
+	 * It can be used to mark the attributes relation and handle them in a common way.
+	 *
+	 *		// Mark blockQuote as a formatting attribute.
+	 *		schema.setAttributeProperties( 'blockQuote', {
+	 *			isFormatting: true
+	 *		} );
+	 *
+	 *		// Override code not to be considered a formatting markup.
+	 *		schema.setAttributeProperties( 'code', {
+	 *			isFormatting: false
+	 *		} );
+	 *
+	 * You can also use custom attributes:
+	 *
+	 *		schema.setAttributeProperties( 'blockQuote', {
+	 *			customAttribute: 'value'
+	 *		} );
+	 *
+	 * Subsequent calls to the same attributes will add up the value:
+	 *
+	 *		schema.setAttributeProperties( 'blockQuote', {
+	 *			one: 1
+	 *		} );
+	 *
+	 *		schema.setAttributeProperties( 'blockQuote', {
+	 *			two: 2
+	 *		} );
+	 *
+	 *		console.log( schema.getAttributeProperties( 'blockQuote' ) );
+	 *		// Logs: {one: 1, two: 2}
+	 *
+	 * @param {String} attributeName Name of the attribute to receive properties.
+	 * @param {module:engine/model/schema~AttributeProperties} properties A dictionary of properties.
+	 */
+	setAttributeProperties( attributeName, properties ) {
+		this._attributeProperties[ attributeName ] = Object.assign( this._attributeProperties[ attributeName ] || {}, properties );
+	}
+
+	/**
+	 * Returns properties assigned to a given attribute.
+	 *
+	 * @param {String} attributeName Name of the attribute.
+	 * @returns {module:engine/model/schema~AttributeProperties}
+	 */
+	getAttributeProperties( attributeName ) {
+		return this._attributeProperties[ attributeName ];
+	}
+
+	/**
+	 * Returns all registered items.
+	 *
+	 * @returns {Object.<String,module:engine/model/schema~SchemaCompiledItemDefinition>}
+	 */
+	getDefinitions() {
+		if ( !this._compiledDefinitions ) {
+			this._compile();
+		}
+
+		return this._compiledDefinitions;
+	}
+
 	/**
 	 * Returns the lowest {@link module:engine/model/schema~Schema#isLimit limit element} containing the entire
 	 * selection/range/position or the root otherwise.
@@ -1285,6 +1344,15 @@ export class SchemaContext {
  * @typedef {Object} module:engine/model/schema~SchemaContextItem
  */
 
+/**
+ * A structure containing additional metadata describing the attribute.
+ *
+ * See {@link module:engine/model/schema~Schema#setAttributeProperties `Schema#setAttributeProperties()`} for usage examples.
+ *
+ * @typedef {Object} module:engine/model/schema~AttributeProperties
+ * @property {Boolean} [isFormatting] Indicates that the attribute should be considered as a visual formatting.
+ */
+
 function compileBaseItemRule( sourceItemRules, itemName ) {
 	const itemRule = {
 		name: itemName,
diff --git a/tests/model/schema.js b/tests/model/schema.js
index a01a6e54b..883112705 100644
--- a/tests/model/schema.js
+++ b/tests/model/schema.js
@@ -96,6 +96,46 @@ describe( 'Schema', () => {
 		} );
 	} );
 
+	describe( 'setAttributeProperties()', () => {
+		beforeEach( () => {
+			schema.register( '$root' );
+			schema.register( 'paragraph', {
+				allowIn: '$root'
+			} );
+			schema.register( '$text', {
+				allowIn: 'paragraph'
+			} );
+			schema.extend( '$text', { allowAttributes: 'testAttribute' } );
+		} );
+
+		it( 'allows registering new properties', () => {
+			schema.setAttributeProperties( 'testAttribute', {
+				foo: 'bar',
+				baz: 'bom'
+			} );
+
+			expect( schema.getAttributeProperties( 'testAttribute' ) ).to.deep.equal( {
+				foo: 'bar',
+				baz: 'bom'
+			} );
+		} );
+
+		it( 'support adding properties in subsequent calls', () => {
+			schema.setAttributeProperties( 'testAttribute', {
+				first: 'foo'
+			} );
+
+			schema.setAttributeProperties( 'testAttribute', {
+				second: 'bar'
+			} );
+
+			expect( schema.getAttributeProperties( 'testAttribute' ) ).to.deep.equal( {
+				first: 'foo',
+				second: 'bar'
+			} );
+		} );
+	} );
+
 	describe( 'getDefinitions()', () => {
 		it( 'returns compiled definitions', () => {
 			schema.register( '$root' );