diff --git a/common/api-review/auth-exp.api.md b/common/api-review/auth-exp.api.md
index a009e94a326..d9a1e801127 100644
--- a/common/api-review/auth-exp.api.md
+++ b/common/api-review/auth-exp.api.md
@@ -218,10 +218,10 @@ export class EmailAuthCredential extends AuthCredential {
 export class EmailAuthProvider implements AuthProvider {
     static credential(email: string, password: string): EmailAuthCredential;
     static credentialWithLink(email: string, emailLink: string): EmailAuthCredential;
-    static readonly EMAIL_LINK_SIGN_IN_METHOD = SignInMethod.EMAIL_LINK;
-    static readonly EMAIL_PASSWORD_SIGN_IN_METHOD = SignInMethod.EMAIL_PASSWORD;
-    static readonly PROVIDER_ID = ProviderId.PASSWORD;
-    readonly providerId = ProviderId.PASSWORD;
+    static readonly EMAIL_LINK_SIGN_IN_METHOD: 'emailLink';
+    static readonly EMAIL_PASSWORD_SIGN_IN_METHOD: 'password';
+    static readonly PROVIDER_ID: 'password';
+    readonly providerId: "password";
 }
 
 export { ErrorFn }
@@ -234,8 +234,8 @@ export class FacebookAuthProvider extends BaseOAuthProvider {
     static credential(accessToken: string): OAuthCredential;
     static credentialFromError(error: FirebaseError): OAuthCredential | null;
     static credentialFromResult(userCredential: UserCredential): OAuthCredential | null;
-    static readonly FACEBOOK_SIGN_IN_METHOD = SignInMethod.FACEBOOK;
-    static readonly PROVIDER_ID = ProviderId.FACEBOOK;
+    static readonly FACEBOOK_SIGN_IN_METHOD: 'facebook.com';
+    static readonly PROVIDER_ID: 'facebook.com';
 }
 
 // @public
@@ -270,8 +270,8 @@ export class GithubAuthProvider extends BaseOAuthProvider {
     static credential(accessToken: string): OAuthCredential;
     static credentialFromError(error: FirebaseError): OAuthCredential | null;
     static credentialFromResult(userCredential: UserCredential): OAuthCredential | null;
-    static readonly GITHUB_SIGN_IN_METHOD = SignInMethod.GITHUB;
-    static readonly PROVIDER_ID = ProviderId.GITHUB;
+    static readonly GITHUB_SIGN_IN_METHOD: 'github.com';
+    static readonly PROVIDER_ID: 'github.com';
 }
 
 // @public
@@ -280,8 +280,8 @@ export class GoogleAuthProvider extends BaseOAuthProvider {
     static credential(idToken?: string | null, accessToken?: string | null): OAuthCredential;
     static credentialFromError(error: FirebaseError): OAuthCredential | null;
     static credentialFromResult(userCredential: UserCredential): OAuthCredential | null;
-    static readonly GOOGLE_SIGN_IN_METHOD = SignInMethod.GOOGLE;
-    static readonly PROVIDER_ID = ProviderId.GOOGLE;
+    static readonly GOOGLE_SIGN_IN_METHOD: 'google.com';
+    static readonly PROVIDER_ID: 'google.com';
 }
 
 // @public
@@ -458,9 +458,9 @@ export class PhoneAuthProvider {
     static credential(verificationId: string, verificationCode: string): PhoneAuthCredential;
     static credentialFromError(error: FirebaseError): AuthCredential | null;
     static credentialFromResult(userCredential: UserCredential): AuthCredential | null;
-    static readonly PHONE_SIGN_IN_METHOD = SignInMethod.PHONE;
-    static readonly PROVIDER_ID = ProviderId.PHONE;
-    readonly providerId = ProviderId.PHONE;
+    static readonly PHONE_SIGN_IN_METHOD: 'phone';
+    static readonly PROVIDER_ID: 'phone';
+    readonly providerId: "phone";
     verifyPhoneNumber(phoneOptions: PhoneInfoOptions | string, applicationVerifier: ApplicationVerifier): Promise<string>;
 }
 
@@ -617,8 +617,8 @@ export class TwitterAuthProvider extends BaseOAuthProvider {
     static credential(token: string, secret: string): OAuthCredential;
     static credentialFromError(error: FirebaseError): OAuthCredential | null;
     static credentialFromResult(userCredential: UserCredential): OAuthCredential | null;
-    static readonly PROVIDER_ID = ProviderId.TWITTER;
-    static readonly TWITTER_SIGN_IN_METHOD = SignInMethod.TWITTER;
+    static readonly PROVIDER_ID: 'twitter.com';
+    static readonly TWITTER_SIGN_IN_METHOD: 'twitter.com';
 }
 
 // @public
diff --git a/packages-exp/auth-exp/src/core/providers/email.ts b/packages-exp/auth-exp/src/core/providers/email.ts
index 3104c01858b..c72a75cb868 100644
--- a/packages-exp/auth-exp/src/core/providers/email.ts
+++ b/packages-exp/auth-exp/src/core/providers/email.ts
@@ -35,15 +35,17 @@ export class EmailAuthProvider implements AuthProvider {
   /**
    * Always set to {@link ProviderId}.PASSWORD, even for email link.
    */
-  static readonly PROVIDER_ID = ProviderId.PASSWORD;
+  static readonly PROVIDER_ID: 'password' = ProviderId.PASSWORD;
   /**
    * Always set to {@link SignInMethod}.EMAIL_PASSWORD.
    */
-  static readonly EMAIL_PASSWORD_SIGN_IN_METHOD = SignInMethod.EMAIL_PASSWORD;
+  static readonly EMAIL_PASSWORD_SIGN_IN_METHOD: 'password' =
+    SignInMethod.EMAIL_PASSWORD;
   /**
    * Always set to {@link SignInMethod}.EMAIL_LINK.
    */
-  static readonly EMAIL_LINK_SIGN_IN_METHOD = SignInMethod.EMAIL_LINK;
+  static readonly EMAIL_LINK_SIGN_IN_METHOD: 'emailLink' =
+    SignInMethod.EMAIL_LINK;
   /**
    * Always set to {@link ProviderId}.PASSWORD, even for email link.
    */
diff --git a/packages-exp/auth-exp/src/core/providers/facebook.ts b/packages-exp/auth-exp/src/core/providers/facebook.ts
index 5dbc38d0af2..7ab304c55f7 100644
--- a/packages-exp/auth-exp/src/core/providers/facebook.ts
+++ b/packages-exp/auth-exp/src/core/providers/facebook.ts
@@ -68,9 +68,10 @@ import { BaseOAuthProvider } from './oauth';
  */
 export class FacebookAuthProvider extends BaseOAuthProvider {
   /** Always set to {@link SignInMethod}.FACEBOOK. */
-  static readonly FACEBOOK_SIGN_IN_METHOD = SignInMethod.FACEBOOK;
+  static readonly FACEBOOK_SIGN_IN_METHOD: 'facebook.com' =
+    SignInMethod.FACEBOOK;
   /** Always set to {@link ProviderId}.FACEBOOK. */
-  static readonly PROVIDER_ID = ProviderId.FACEBOOK;
+  static readonly PROVIDER_ID: 'facebook.com' = ProviderId.FACEBOOK;
 
   constructor() {
     super(ProviderId.FACEBOOK);
diff --git a/packages-exp/auth-exp/src/core/providers/github.ts b/packages-exp/auth-exp/src/core/providers/github.ts
index 2b08a3784f2..0a0f1cc8e63 100644
--- a/packages-exp/auth-exp/src/core/providers/github.ts
+++ b/packages-exp/auth-exp/src/core/providers/github.ts
@@ -71,9 +71,9 @@ import { BaseOAuthProvider } from './oauth';
  */
 export class GithubAuthProvider extends BaseOAuthProvider {
   /** Always set to {@link SignInMethod}.GITHUB. */
-  static readonly GITHUB_SIGN_IN_METHOD = SignInMethod.GITHUB;
+  static readonly GITHUB_SIGN_IN_METHOD: 'github.com' = SignInMethod.GITHUB;
   /** Always set to {@link ProviderId}.GITHUB. */
-  static readonly PROVIDER_ID = ProviderId.GITHUB;
+  static readonly PROVIDER_ID: 'github.com' = ProviderId.GITHUB;
 
   constructor() {
     super(ProviderId.GITHUB);
diff --git a/packages-exp/auth-exp/src/core/providers/google.ts b/packages-exp/auth-exp/src/core/providers/google.ts
index a95397c0de6..82b08ea7f6e 100644
--- a/packages-exp/auth-exp/src/core/providers/google.ts
+++ b/packages-exp/auth-exp/src/core/providers/google.ts
@@ -71,9 +71,9 @@ import { BaseOAuthProvider } from './oauth';
  */
 export class GoogleAuthProvider extends BaseOAuthProvider {
   /** Always set to {@link SignInMethod}.GOOGLE. */
-  static readonly GOOGLE_SIGN_IN_METHOD = SignInMethod.GOOGLE;
+  static readonly GOOGLE_SIGN_IN_METHOD: 'google.com' = SignInMethod.GOOGLE;
   /** Always set to {@link ProviderId}.GOOGLE. */
-  static readonly PROVIDER_ID = ProviderId.GOOGLE;
+  static readonly PROVIDER_ID: 'google.com' = ProviderId.GOOGLE;
 
   constructor() {
     super(ProviderId.GOOGLE);
diff --git a/packages-exp/auth-exp/src/core/providers/twitter.ts b/packages-exp/auth-exp/src/core/providers/twitter.ts
index 74e1f5e32d3..e83924db18b 100644
--- a/packages-exp/auth-exp/src/core/providers/twitter.ts
+++ b/packages-exp/auth-exp/src/core/providers/twitter.ts
@@ -86,9 +86,9 @@ import { BaseOAuthProvider } from './oauth';
  */
 export class TwitterAuthProvider extends BaseOAuthProvider {
   /** Always set to {@link SignInMethod}.TWITTER. */
-  static readonly TWITTER_SIGN_IN_METHOD = SignInMethod.TWITTER;
+  static readonly TWITTER_SIGN_IN_METHOD: 'twitter.com' = SignInMethod.TWITTER;
   /** Always set to {@link ProviderId}.TWITTER. */
-  static readonly PROVIDER_ID = ProviderId.TWITTER;
+  static readonly PROVIDER_ID: 'twitter.com' = ProviderId.TWITTER;
 
   constructor() {
     super(ProviderId.TWITTER);
diff --git a/packages-exp/auth-exp/src/model/id_token.ts b/packages-exp/auth-exp/src/model/id_token.ts
index d66aacd1498..95580f9f977 100644
--- a/packages-exp/auth-exp/src/model/id_token.ts
+++ b/packages-exp/auth-exp/src/model/id_token.ts
@@ -15,8 +15,6 @@
  * limitations under the License.
  */
 
-import { ProviderId } from './public_types';
-
 import { PhoneOrOauthTokenResponse } from '../api/authentication/mfa';
 
 /**
@@ -55,7 +53,7 @@ export interface IdTokenResponse {
   idToken?: IdToken;
   refreshToken?: string;
   expiresIn?: string;
-  providerId?: ProviderId | string;
+  providerId?: string;
 
   // Used in AdditionalUserInfo
   displayName?: string | null;
diff --git a/packages-exp/auth-exp/src/platform_browser/providers/phone.ts b/packages-exp/auth-exp/src/platform_browser/providers/phone.ts
index 86103423c45..849b891062a 100644
--- a/packages-exp/auth-exp/src/platform_browser/providers/phone.ts
+++ b/packages-exp/auth-exp/src/platform_browser/providers/phone.ts
@@ -53,9 +53,9 @@ import { TaggedWithTokenResponse } from '../../model/id_token';
  */
 export class PhoneAuthProvider {
   /** Always set to {@link ProviderId}.PHONE. */
-  static readonly PROVIDER_ID = ProviderId.PHONE;
+  static readonly PROVIDER_ID: 'phone' = ProviderId.PHONE;
   /** Always set to {@link SignInMethod}.PHONE. */
-  static readonly PHONE_SIGN_IN_METHOD = SignInMethod.PHONE;
+  static readonly PHONE_SIGN_IN_METHOD: 'phone' = SignInMethod.PHONE;
 
   /** Always set to {@link ProviderId}.PHONE. */
   readonly providerId = PhoneAuthProvider.PROVIDER_ID;