diff --git a/common/api-review/functions.api.md b/common/api-review/functions.api.md
index 8ce13d974ba..abc730bc1c8 100644
--- a/common/api-review/functions.api.md
+++ b/common/api-review/functions.api.md
@@ -5,6 +5,7 @@
 ```ts
 
 import { FirebaseApp } from '@firebase/app';
+import { FirebaseError } from '@firebase/app';
 
 // @public
 export function connectFunctionsEmulator(functionsInstance: Functions, host: string, port: number): void;
@@ -16,6 +17,14 @@ export interface Functions {
     region: string;
 }
 
+// @public
+export class FunctionsError extends FirebaseError {
+    constructor(
+    code: FunctionsErrorCodeCore, message?: string,
+    details?: unknown);
+    readonly details?: unknown;
+}
+
 // @public
 export type FunctionsErrorCode = `functions/${FunctionsErrorCodeCore}`;
 
diff --git a/packages/functions/src/callable.test.ts b/packages/functions/src/callable.test.ts
index a2036046f1a..274419f6b2d 100644
--- a/packages/functions/src/callable.test.ts
+++ b/packages/functions/src/callable.test.ts
@@ -17,7 +17,7 @@
 import { expect } from 'chai';
 import * as sinon from 'sinon';
 import { FirebaseApp } from '@firebase/app';
-import { FunctionsErrorCodeCore } from './public-types';
+import { FunctionsError, FunctionsErrorCodeCore } from './public-types';
 import {
   Provider,
   ComponentContainer,
@@ -39,7 +39,6 @@ import {
 import { makeFakeApp, createTestService } from '../test/utils';
 import { httpsCallable } from './service';
 import { FUNCTIONS_TYPE } from './constants';
-import { FunctionsError } from './error';
 
 // eslint-disable-next-line @typescript-eslint/no-require-imports
 export const TEST_PROJECT = require('../../../config/project.json');
diff --git a/packages/functions/src/error.ts b/packages/functions/src/error.ts
index 62d5ecb6a4f..16515b8f5d4 100644
--- a/packages/functions/src/error.ts
+++ b/packages/functions/src/error.ts
@@ -15,11 +15,9 @@
  * limitations under the License.
  */
 
-import { FunctionsErrorCodeCore as FunctionsErrorCode } from './public-types';
+import { FunctionsError, FunctionsErrorCodeCore } from './public-types';
 import { decode } from './serializer';
 import { HttpResponseBody } from './service';
-import { FirebaseError } from '@firebase/util';
-import { FUNCTIONS_TYPE } from './constants';
 
 /**
  * Standard error codes for different ways a request can fail, as defined by:
@@ -28,7 +26,7 @@ import { FUNCTIONS_TYPE } from './constants';
  * This map is used primarily to convert from a backend error code string to
  * a client SDK error code string, and make sure it's in the supported set.
  */
-const errorCodeMap: { [name: string]: FunctionsErrorCode } = {
+const errorCodeMap: { [name: string]: FunctionsErrorCodeCore } = {
   OK: 'ok',
   CANCELLED: 'cancelled',
   UNKNOWN: 'unknown',
@@ -48,28 +46,6 @@ const errorCodeMap: { [name: string]: FunctionsErrorCode } = {
   DATA_LOSS: 'data-loss'
 };
 
-/**
- * An explicit error that can be thrown from a handler to send an error to the
- * client that called the function.
- */
-export class FunctionsError extends FirebaseError {
-  constructor(
-    /**
-     * A standard error code that will be returned to the client. This also
-     * determines the HTTP status code of the response, as defined in code.proto.
-     */
-    code: FunctionsErrorCode,
-    message?: string,
-    /**
-     * Extra data to be converted to JSON and included in the error response.
-     */
-    readonly details?: unknown
-  ) {
-    super(`${FUNCTIONS_TYPE}/${code}`, message || '');
-    // TODO (dlarocque): Set this to be the root of the stack trace.
-  }
-}
-
 /**
  * Takes an HTTP status code and returns the corresponding ErrorCode.
  * This is the standard HTTP status code -> error mapping defined in:
@@ -78,7 +54,7 @@ export class FunctionsError extends FirebaseError {
  * @param status An HTTP status code.
  * @return The corresponding ErrorCode, or ErrorCode.UNKNOWN if none.
  */
-function codeForHTTPStatus(status: number): FunctionsErrorCode {
+function codeForHTTPStatus(status: number): FunctionsErrorCodeCore {
   // Make sure any successful status is OK.
   if (status >= 200 && status < 300) {
     return 'ok';
diff --git a/packages/functions/src/public-types.ts b/packages/functions/src/public-types.ts
index 311493d5fda..de8c6aecb5d 100644
--- a/packages/functions/src/public-types.ts
+++ b/packages/functions/src/public-types.ts
@@ -14,7 +14,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { FirebaseApp } from '@firebase/app';
+import { FirebaseApp, FirebaseError } from '@firebase/app';
+import { FUNCTIONS_TYPE } from './constants';
 
 /**
  * An `HttpsCallableResult` wraps a single result from a function call.
@@ -143,6 +144,29 @@ export type FunctionsErrorCodeCore =
  */
 export type FunctionsErrorCode = `functions/${FunctionsErrorCodeCore}`;
 
+/**
+ * An explicit error that can be thrown from a handler to send an error to the
+ * client that called the function.
+ *
+ * @public
+ */
+export class FunctionsError extends FirebaseError {
+  constructor(
+    /**
+     * A standard error code that will be returned to the client. This also
+     * determines the HTTP status code of the response, as defined in code.proto.
+     */
+    code: FunctionsErrorCodeCore,
+    message?: string,
+    /**
+     * Extra data to be converted to JSON and included in the error response.
+     */
+    readonly details?: unknown
+  ) {
+    super(`${FUNCTIONS_TYPE}/${code}`, message || '');
+  }
+}
+
 declare module '@firebase/component' {
   interface NameServiceMapping {
     'functions': Functions;
diff --git a/packages/functions/src/service.ts b/packages/functions/src/service.ts
index c5fe7fa8a85..2c8ff099fe5 100644
--- a/packages/functions/src/service.ts
+++ b/packages/functions/src/service.ts
@@ -17,11 +17,12 @@
 
 import { FirebaseApp, _FirebaseService } from '@firebase/app';
 import {
+  FunctionsError,
   HttpsCallable,
   HttpsCallableResult,
   HttpsCallableOptions
 } from './public-types';
-import { _errorForResponse, FunctionsError } from './error';
+import { _errorForResponse } from './error';
 import { ContextProvider } from './context';
 import { encode, decode } from './serializer';
 import { Provider } from '@firebase/component';