diff --git a/src/trix/config/html_sanitizer_allowed_attributes.js b/src/trix/config/html_sanitizer_allowed_attributes.js
new file mode 100644
index 000000000..27bc6f871
--- /dev/null
+++ b/src/trix/config/html_sanitizer_allowed_attributes.js
@@ -0,0 +1,10 @@
+const attributes = [
+  "style",
+  "href",
+  "src",
+  "width",
+  "height",
+  "class",
+]
+
+export default attributes
diff --git a/src/trix/config/html_sanitizer_allowed_elements.js b/src/trix/config/html_sanitizer_allowed_elements.js
new file mode 100644
index 000000000..68580c96c
--- /dev/null
+++ b/src/trix/config/html_sanitizer_allowed_elements.js
@@ -0,0 +1,3 @@
+const allowedElements = []
+
+export default allowedElements
diff --git a/src/trix/config/html_sanitizer_allowed_protocols.js b/src/trix/config/html_sanitizer_allowed_protocols.js
new file mode 100644
index 000000000..286823a0f
--- /dev/null
+++ b/src/trix/config/html_sanitizer_allowed_protocols.js
@@ -0,0 +1,3 @@
+const allowedProtocols = []
+
+export default allowedProtocols
diff --git a/src/trix/config/html_sanitizer_forbidden_elements.js b/src/trix/config/html_sanitizer_forbidden_elements.js
new file mode 100644
index 000000000..7641ab742
--- /dev/null
+++ b/src/trix/config/html_sanitizer_forbidden_elements.js
@@ -0,0 +1,7 @@
+const forbiddenElements = [
+  "script",
+  "iframe",
+  "form",
+]
+
+export default forbiddenElements
diff --git a/src/trix/config/html_sanitizer_forbidden_protocols.js b/src/trix/config/html_sanitizer_forbidden_protocols.js
new file mode 100644
index 000000000..8b8f7b28d
--- /dev/null
+++ b/src/trix/config/html_sanitizer_forbidden_protocols.js
@@ -0,0 +1,5 @@
+const forbiddenProtocols = [
+  "javascript:",
+]
+
+export default forbiddenProtocols
diff --git a/src/trix/config/index.js b/src/trix/config/index.js
index 27f7abc2f..202cc5cf9 100644
--- a/src/trix/config/index.js
+++ b/src/trix/config/index.js
@@ -10,3 +10,8 @@ export { default as parser } from "./parser"
 export { default as textAttributes } from "./text_attributes"
 export { default as toolbar } from "./toolbar"
 export { default as undo } from "./undo"
+export { default as htmlSanitizerAllowedAttributes } from "./html_sanitizer_allowed_attributes"
+export { default as htmlSanitizerAllowedElements } from "./html_sanitizer_allowed_elements"
+export { default as htmlSanitizerAllowedProtocols } from "./html_sanitizer_allowed_protocols"
+export { default as htmlSanitizerForbiddenElements } from "./html_sanitizer_forbidden_elements"
+export { default as htmlSanitizerForbiddenProtocols } from "./html_sanitizer_forbidden_protocols"
diff --git a/src/trix/models/html_sanitizer.js b/src/trix/models/html_sanitizer.js
index 6e342e51a..92616075d 100644
--- a/src/trix/models/html_sanitizer.js
+++ b/src/trix/models/html_sanitizer.js
@@ -1,10 +1,13 @@
 import BasicObject from "trix/core/basic_object"
 
 import { nodeIsAttachmentElement, removeNode, tagName, walkTree } from "trix/core/helpers"
-
-const DEFAULT_ALLOWED_ATTRIBUTES = "style href src width height class".split(" ")
-const DEFAULT_FORBIDDEN_PROTOCOLS = "javascript:".split(" ")
-const DEFAULT_FORBIDDEN_ELEMENTS = "script iframe form".split(" ")
+import {
+  htmlSanitizerAllowedAttributes,
+  htmlSanitizerAllowedElements,
+  htmlSanitizerAllowedProtocols,
+  htmlSanitizerForbiddenElements,
+  htmlSanitizerForbiddenProtocols
+} from "../config"
 
 export default class HTMLSanitizer extends BasicObject {
   static sanitize(html, options) {
@@ -13,11 +16,13 @@ export default class HTMLSanitizer extends BasicObject {
     return sanitizer
   }
 
-  constructor(html, { allowedAttributes, forbiddenProtocols, forbiddenElements } = {}) {
+  constructor(html, { allowedAttributes, allowedElements, allowedProtocols, forbiddenProtocols, forbiddenElements } = {}) {
     super(...arguments)
-    this.allowedAttributes = allowedAttributes || DEFAULT_ALLOWED_ATTRIBUTES
-    this.forbiddenProtocols = forbiddenProtocols || DEFAULT_FORBIDDEN_PROTOCOLS
-    this.forbiddenElements = forbiddenElements || DEFAULT_FORBIDDEN_ELEMENTS
+    this.allowedAttributes = allowedAttributes || htmlSanitizerAllowedAttributes
+    this.allowedElements = allowedElements || htmlSanitizerAllowedElements
+    this.allowedProtocols = allowedProtocols || htmlSanitizerAllowedProtocols
+    this.forbiddenElements = forbiddenElements || htmlSanitizerForbiddenElements
+    this.forbiddenProtocols = forbiddenProtocols || htmlSanitizerForbiddenProtocols
     this.body = createBodyElementForHTML(html)
   }
 
@@ -63,7 +68,7 @@ export default class HTMLSanitizer extends BasicObject {
 
   sanitizeElement(element) {
     if (element.hasAttribute("href")) {
-      if (this.forbiddenProtocols.includes(element.protocol)) {
+      if (this.forbiddenProtocols.includes(element.protocol) || this.allowedProtocols.length > 0 && !this.allowedProtocols.includes(element.protocol)) {
         element.removeAttribute("href")
       }
     }
@@ -96,7 +101,7 @@ export default class HTMLSanitizer extends BasicObject {
   }
 
   elementIsForbidden(element) {
-    return this.forbiddenElements.includes(tagName(element))
+    return this.forbiddenElements.includes(tagName(element)) || this.allowedElements.length > 0 && !this.allowedElements.includes(tagName(element))
   }
 
   elementIsntSerializable(element) {
diff --git a/src/trix/views/piece_view.js b/src/trix/views/piece_view.js
index c03d6c266..306478183 100644
--- a/src/trix/views/piece_view.js
+++ b/src/trix/views/piece_view.js
@@ -111,17 +111,25 @@ export default class PieceView extends ObjectView {
   }
 
   createContainerElement() {
+    const attributes = {}
+    let groupTagName
+
     for (const key in this.attributes) {
       const value = this.attributes[key]
       const config = getTextConfig(key)
       if (config) {
-        if (config.groupTagName) {
-          const attributes = {}
+        if (!groupTagName && config.groupTagName) {
+          attributes[key] = value
+          groupTagName = config.groupTagName
+        } else if (config.groupTagName && groupTagName === config.groupTagName) {
           attributes[key] = value
-          return makeElement(config.groupTagName, attributes)
         }
       }
     }
+
+    if (Object.entries(attributes).length > 0 && groupTagName) {
+      return makeElement(groupTagName, attributes)
+    }
   }
 
   preserveSpaces(string) {