diff --git a/README.md b/README.md
index fa6c0d8..a79a6db 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # ![Bolt Icon](docs/images/flash.png) Bolt Compiler
 
-[![Build Status](https://travis-ci.org/firebase/bolt.svg?branch=master)](https://travis-ci.org/firebase/bolt)
+[![Build Status](https://travis-ci.org/FirebaseExtended/bolt.svg?branch=master)](https://travis-ci.org/FirebaseExtended/bolt)
 [![NPM Version](https://badge.fury.io/js/firebase-bolt.svg)](https://npmjs.org/package/firebase-bolt)
 [![NPM Downloads](http://img.shields.io/npm/dm/firebase-bolt.svg)](https://npmjs.org/package/firebase-bolt)
 
@@ -11,7 +11,7 @@ using with production applications.
 
 Otherwise, we'd love to have feedback from early adopters.  You can email questions
 to firebase-talk@googlegroups.com using "Bolt" in the subject line, or post bugs
-on our [Issue Tracker](https://github.com/firebase/bolt/issues).
+on our [Issue Tracker](https://github.com/FirebaseExtended/bolt/issues).
 
 # Language Definition
 
diff --git a/docs/language.md b/docs/language.md
index 6c377bf..45c5fe4 100644
--- a/docs/language.md
+++ b/docs/language.md
@@ -31,6 +31,7 @@ A (user-defined) type statement describes a value that can be stored in the Fire
 type MyType [extends BaseType] {
   property1: Type,
   property2: Type,
+  $wildcardProp: Type
   ...
 
   validate() { <validation expression> }
@@ -55,6 +56,12 @@ to use any other character in a property name, you can enclose them in quotes (n
 that Firebase allows any character in a path *except* for `.`, `$`, `#`, `[`, `[`, `/`,
 or control characters).
 
+When a type statement contains a wildcard property, i.e. a property starting with the 
+`$`-character, the value is allowed to have an arbitrary number of extra properties. When
+there is no wildcard property, the value can only have the properties defined in the
+type statement. A type can have at most one wildcard property.
+
+
 Built-in base types are also similar to JavaScript types:
 
     String            - Character strings
diff --git a/samples/issue-212.bolt b/samples/issue-212.bolt
new file mode 100644
index 0000000..1fe1fc4
--- /dev/null
+++ b/samples/issue-212.bolt
@@ -0,0 +1,40 @@
+type MyType {
+  num: Number;
+  str: String;
+  any: Any;
+  $extras: String;
+}
+
+type AnyMap {
+  $extras: Any;
+}
+
+type OtherType extends AnyMap {
+  name: String;
+}
+
+type WithExtras<T> extends T {
+  $extras: Any;
+}
+
+type AnotherType {
+  name: String;
+}
+
+
+path /path is MyType {
+  read() { true }
+  write() { true }
+}
+
+path /other is OtherType {
+  read() { true }
+}
+
+path /another is AnotherType {
+  read() { true }
+}
+
+path /anotherWithExtras is WithExtras<AnotherType> {
+  read() { true }
+}
diff --git a/samples/issue-212.json b/samples/issue-212.json
new file mode 100644
index 0000000..95bed69
--- /dev/null
+++ b/samples/issue-212.json
@@ -0,0 +1,45 @@
+{
+  "rules": {
+    "path": {
+      ".validate": "newData.hasChildren(['num', 'str', 'any'])",
+      "num": {
+        ".validate": "newData.isNumber()"
+      },
+      "str": {
+        ".validate": "newData.isString()"
+      },
+      "any": {
+        ".validate": "true"
+      },
+      "$extras": {
+        ".validate": "newData.isString()"
+      },
+      ".read": "true",
+      ".write": "true"
+    },
+    "other": {
+      ".validate": "newData.hasChildren(['name'])",
+      "name": {
+        ".validate": "newData.isString()"
+      },
+      ".read": "true"
+    },
+    "another": {
+      ".validate": "newData.hasChildren(['name'])",
+      "name": {
+        ".validate": "newData.isString()"
+      },
+      "$other": {
+        ".validate": "false"
+      },
+      ".read": "true"
+    },
+    "anotherWithExtras": {
+      ".validate": "newData.hasChildren(['name'])",
+      "name": {
+        ".validate": "newData.isString()"
+      },
+      ".read": "true"
+    }
+  }
+}
diff --git a/src/rules-generator.ts b/src/rules-generator.ts
index 25de82d..9b5f947 100644
--- a/src/rules-generator.ts
+++ b/src/rules-generator.ts
@@ -448,6 +448,7 @@ export class Generator {
     let wildProperties = 0;
     Object.keys(schema.properties).forEach((propName) => {
       if (propName[0] === '$') {
+        delete validator.$other;
         wildProperties += 1;
         if (INVALID_KEY_REGEX.test(propName.slice(1))) {
           this.fatal(errors.invalidPropertyName + propName);
@@ -467,7 +468,7 @@ export class Generator {
       extendValidator(<Validator> validator[propName], this.ensureValidator(propType));
     });
 
-    if (wildProperties > 1 || wildProperties === 1 && requiredProperties.length > 0) {
+    if (wildProperties > 1) {
       this.fatal(errors.invalidWildChildren);
     }
 
@@ -478,7 +479,11 @@ export class Generator {
     }
 
     // Disallow $other properties by default
-    if (hasProps) {
+    let hasWildProps = Object.keys(validator).some((v) => {
+        return v[0] === '$';
+    });
+
+    if (hasProps && !hasWildProps) {
       validator['$other'] = {};
       extendValidator(<Validator> validator['$other'],
                       <Validator> {'.validate': ast.boolean(false)});
diff --git a/src/test/sample-files.ts b/src/test/sample-files.ts
index 8dab860..ef9aeca 100644
--- a/src/test/sample-files.ts
+++ b/src/test/sample-files.ts
@@ -13,6 +13,7 @@ export let samples = [
   "issue-169",
   "issue-232",
   "issue-97",
+  "issue-212",
   "mail",
   "map-scalar",
   "multi-update",