diff --git a/entrypoints.json b/entrypoints.json
index caa92a7604..96c3f52e73 100644
--- a/entrypoints.json
+++ b/entrypoints.json
@@ -16,6 +16,10 @@
     "typings": "./lib/auth/index.d.ts",
     "dist": "./lib/auth/index.js"
   },
+  "firebase-admin/fpnv": {
+    "typings": "./lib/fpnv/index.d.ts",
+    "dist": "./lib/fpnv/index.js"
+  },
   "firebase-admin/database": {
     "typings": "./lib/database/index.d.ts",
     "dist": "./lib/database/index.js"
diff --git a/etc/firebase-admin.fpnv.api.md b/etc/firebase-admin.fpnv.api.md
new file mode 100644
index 0000000000..ef7cf2df2f
--- /dev/null
+++ b/etc/firebase-admin.fpnv.api.md
@@ -0,0 +1,32 @@
+## API Report File for "firebase-admin.fpnv"
+
+> Do not edit this file. It is a report generated by [API Extractor](https://api-extractor.com/).
+
+```ts
+
+import { Agent } from 'http';
+
+// @public
+export class Fpnv {
+    // Warning: (ae-forgotten-export) The symbol "App" needs to be exported by the entry point index.d.ts
+    get app(): App;
+    verifyToken(fpnvJwt: string): Promise<FpnvToken>;
+}
+
+// @public
+export interface FpnvToken {
+    [key: string]: any;
+    aud: string[];
+    exp: number;
+    getPhoneNumber(): string;
+    iat: number;
+    iss: string;
+    jti: string;
+    nonce: string;
+    sub: string;
+}
+
+// @public
+export function getFirebasePnv(app?: App): Fpnv;
+
+```
diff --git a/package.json b/package.json
index a17a1e291f..7a33f881be 100644
--- a/package.json
+++ b/package.json
@@ -73,6 +73,9 @@
       "auth": [
         "lib/auth"
       ],
+      "fpnv": [
+        "lib/fpnv"
+      ],
       "eventarc": [
         "lib/eventarc"
       ],
@@ -134,6 +137,11 @@
       "require": "./lib/auth/index.js",
       "import": "./lib/esm/auth/index.js"
     },
+    "./fpnv": {
+      "types": "./lib/fpnv/index.d.ts",
+      "require": "./lib/fpnv/index.js",
+      "import": "./lib/esm/fpnv/index.js"
+    },
     "./database": {
       "types": "./lib/database/index.d.ts",
       "require": "./lib/database/index.js",
diff --git a/src/fpnv/fpnv-api-client-internal.ts b/src/fpnv/fpnv-api-client-internal.ts
new file mode 100644
index 0000000000..e4a74596c0
--- /dev/null
+++ b/src/fpnv/fpnv-api-client-internal.ts
@@ -0,0 +1,71 @@
+/*!
+ * @license
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { PrefixedFirebaseError } from '../utils/error';
+
+export interface FirebasePhoneNumberTokenInfo {
+  /** Documentation URL. */
+  url: string;
+  /** verify API name. */
+  verifyApiName: string;
+  /** The JWT full name. */
+  jwtName: string;
+  /** The JWT short name. */
+  shortName: string;
+  /** The JWT typ (Type) */
+  typ: string;
+}
+
+export const JWKS_URL = 'https://fpnv.googleapis.com/v1beta/jwks';
+
+export const PN_TOKEN_INFO: FirebasePhoneNumberTokenInfo = {
+  url: 'https://firebase.google.com/docs/phone-number-verification',
+  verifyApiName: 'verifyToken()',
+  jwtName: 'Firebase Phone Verification token',
+  shortName: 'FPNV token',
+  typ: 'JWT',
+};
+
+export const FPNV_ERROR_CODE_MAPPING = {
+  INVALID_ARGUMENT: 'invalid-argument',
+  INVALID_TOKEN: 'invalid-token',
+  EXPIRED_TOKEN: 'expired-token',
+} satisfies Record<string, FpnvErrorCode>;
+
+export type FpnvErrorCode =
+  | 'invalid-argument'
+  | 'invalid-token'
+  | 'expired-token'
+
+/**
+ * Firebase Phone Number Verification error code structure. This extends `PrefixedFirebaseError`.
+ *
+ * @param code - The error code.
+ * @param message - The error message.
+ * @constructor
+ */
+export class FirebaseFpnvError extends PrefixedFirebaseError {
+  constructor(code: FpnvErrorCode, message: string) {
+    super('fpnv', code, message);
+
+    /* tslint:disable:max-line-length */
+    // Set the prototype explicitly. See the following link for more details:
+    // https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#extending-built-ins-like-error-array-and-map-may-no-longer-work
+    /* tslint:enable:max-line-length */
+    (this as any).__proto__ = FirebaseFpnvError.prototype;
+  }
+}
diff --git a/src/fpnv/fpnv-api.ts b/src/fpnv/fpnv-api.ts
new file mode 100644
index 0000000000..abc33d8cc6
--- /dev/null
+++ b/src/fpnv/fpnv-api.ts
@@ -0,0 +1,81 @@
+/*!
+ * @license
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+/**
+ * Interface representing a Fpnv token.
+ */
+export interface FpnvToken {
+    /**
+     * The issuer identifier for the issuer of the response.
+     * This value is a URL with the format
+     * `https://fpnv.googleapis.com/projects/<PROJECT_NUMBER>`, where `<PROJECT_NUMBER>` is the
+     * same project number specified in the {@link FpnvToken.aud} property.
+     */
+    iss: string;
+
+    /**
+     * The audience for which this token is intended.
+     * This value is a string array, one of which is a URL with the format
+     * `https://fpnv.googleapis.com/projects/<PROJECT_NUMBER>`, where `<PROJECT_NUMBER>` is the
+     * project number of your Firebase project.
+     */
+    aud: string[];
+
+    /**
+     * The Fpnv token's expiration time, in seconds since the Unix epoch. That is, the
+     * time at which this Fpnv token expires and should no longer be considered valid.
+     */
+    exp: number;
+
+    /**
+     * The Fpnv token's issued-at time, in seconds since the Unix epoch. That is, the
+     * time at which this Fpnv token was issued and should start to be considered
+     * valid.
+     */
+    iat: number;
+
+    /**
+     * The phone number of User.
+     */
+    sub: string;
+
+    /**
+     * A case-sensitive string that uniquely identifies a specific JWT instance
+     */
+    jti: string;
+
+    /**
+     * A unique, single-use "number used once" value.
+     */
+    nonce: string;
+
+    /**
+     * The corresponding user's phone number.
+     * This value is not actually one of the JWT token claims. It is added as a
+     * convenience, and is set as the value of the {@link FpnvToken.sub} property.
+     */
+    getPhoneNumber(): string;
+
+    /**
+     * Other arbitrary claims included in the token.
+     */
+    [key: string]: any;
+}
+
+export { FpnvErrorCode, FirebaseFpnvError } from './fpnv-api-client-internal';
+
diff --git a/src/fpnv/fpnv.ts b/src/fpnv/fpnv.ts
new file mode 100644
index 0000000000..cc3cd13a3e
--- /dev/null
+++ b/src/fpnv/fpnv.ts
@@ -0,0 +1,64 @@
+/*!
+ * @license
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { App } from '../app';
+import { FpnvToken } from './fpnv-api';
+import { FirebasePhoneNumberTokenVerifier } from './token-verifier';
+import { JWKS_URL, PN_TOKEN_INFO } from './fpnv-api-client-internal';
+
+/**
+ * Fpnv service bound to the provided app.
+ */
+export class Fpnv {
+  private readonly appInternal: App;
+  private readonly fpnvVerifier: FirebasePhoneNumberTokenVerifier;
+
+  /**
+   * @param app - The app for this `Fpnv` service.
+   * @constructor
+   * @internal
+   */
+  constructor(app: App) {
+
+    this.appInternal = app;
+    this.fpnvVerifier = new FirebasePhoneNumberTokenVerifier(
+      JWKS_URL,
+      'https://fpnv.googleapis.com/projects/',
+      PN_TOKEN_INFO,
+      app
+    );
+  }
+
+  /**
+   * Returns the app associated with this `Fpnv` instance.
+   *
+   * @returns The app associated with this `Fpnv` instance.
+   */
+  get app(): App {
+    return this.appInternal;
+  }
+
+  /**
+   * Verifies a Firebase Phone Number Verification token (FPNV JWT).
+   *
+   * @param fpnvJwt - The FPNV JWT string to verify.
+   * @returns A promise that resolves with the decoded token.
+   */
+  public verifyToken(fpnvJwt: string): Promise<FpnvToken> {
+    return this.fpnvVerifier.verifyJWT(fpnvJwt);
+  }
+}
diff --git a/src/fpnv/index.ts b/src/fpnv/index.ts
new file mode 100644
index 0000000000..90d96bff92
--- /dev/null
+++ b/src/fpnv/index.ts
@@ -0,0 +1,64 @@
+/**
+ * Firebase Phone Number Verification.
+ *
+ * @packageDocumentation
+ */
+
+/*!
+ * @license
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { App, getApp } from '../app';
+import { FirebaseApp } from '../app/firebase-app';
+import { Fpnv } from './fpnv';
+
+export {
+  Fpnv
+} from './fpnv';
+
+export {
+  FpnvToken,
+} from './fpnv-api'
+
+/**
+ * Gets the {@link Fpnv} service for the default app or a
+ * given app.
+ *
+ * `getFirebasePnv()` can be called with no arguments to access the default app's
+ * {@link Fpnv} service or as `getFirebasePnv(app)` to access the
+ * {@link Fpnv} service associated with a specific app.
+ *
+ * @example
+ * ```javascript
+ * // Get the Fpnv service for the default app
+ * const defaultFpnv = getFirebasePnv();
+ * ```
+ *
+ * @example
+ * ```javascript
+ * // Get the Fpnv service for a given app
+ * const otherFpnv = getFirebasePnv(otherApp);
+ * ```
+ *
+ */
+export function getFirebasePnv(app?: App): Fpnv {
+  if (typeof app === 'undefined') {
+    app = getApp();
+  }
+
+  const firebaseApp: FirebaseApp = app as FirebaseApp;
+  return firebaseApp.getOrInitService('fpnv', (app) => new Fpnv(app));
+}
diff --git a/src/fpnv/token-verifier.ts b/src/fpnv/token-verifier.ts
new file mode 100644
index 0000000000..39265b1c84
--- /dev/null
+++ b/src/fpnv/token-verifier.ts
@@ -0,0 +1,203 @@
+/*!
+ * @license
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { App } from '../app';
+import { FirebaseFpnvError, FpnvToken } from './fpnv-api';
+import * as util from '../utils/index';
+import * as validator from '../utils/validator';
+import {
+  DecodedToken, decodeJwt, JwtError, JwtErrorCode,
+  PublicKeySignatureVerifier, ALGORITHM_ES256, SignatureVerifier,
+} from '../utils/jwt';
+import { FirebasePhoneNumberTokenInfo, FPNV_ERROR_CODE_MAPPING } from './fpnv-api-client-internal';
+
+export class FirebasePhoneNumberTokenVerifier {
+  private readonly shortNameArticle: string;
+  private readonly signatureVerifier: SignatureVerifier;
+
+  constructor(
+    jwksUrl: string,
+    private issuer: string,
+    private tokenInfo: FirebasePhoneNumberTokenInfo,
+    private readonly app: App
+  ) {
+
+    if (!validator.isURL(jwksUrl)) {
+      throw new FirebaseFpnvError(
+        FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT,
+        'The provided public client certificate URL is an invalid URL.',
+      );
+    } else if (!validator.isURL(issuer)) {
+      throw new FirebaseFpnvError(
+        FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT,
+        'The provided JWT issuer is an invalid URL.',
+      );
+    } else if (!validator.isNonNullObject(tokenInfo)) {
+      throw new FirebaseFpnvError(
+        FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT,
+        'The provided JWT information is not an object or null.',
+      );
+    } else if (!validator.isURL(tokenInfo.url)) {
+      throw new FirebaseFpnvError(
+        FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT,
+        'The provided JWT verification documentation URL is invalid.',
+      );
+    } else if (!validator.isNonEmptyString(tokenInfo.verifyApiName)) {
+      throw new FirebaseFpnvError(
+        FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT,
+        'The JWT verify API name must be a non-empty string.',
+      );
+    } else if (!validator.isNonEmptyString(tokenInfo.jwtName)) {
+      throw new FirebaseFpnvError(
+        FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT,
+        'The JWT public full name must be a non-empty string.',
+      );
+    } else if (!validator.isNonEmptyString(tokenInfo.shortName)) {
+      throw new FirebaseFpnvError(
+        FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT,
+        'The JWT public short name must be a non-empty string.',
+      );
+    }
+    this.shortNameArticle = tokenInfo.shortName.charAt(0).match(/[aeiou]/i) ? 'an' : 'a';
+
+    this.signatureVerifier = PublicKeySignatureVerifier.withJwksUrl(jwksUrl, app.options.httpAgent);
+
+    // For backward compatibility, the project ID is validated in the verification call.
+  }
+
+  public async verifyJWT(jwtToken: string): Promise<FpnvToken> {
+    if (!validator.isString(jwtToken)) {
+      throw new FirebaseFpnvError(
+        FPNV_ERROR_CODE_MAPPING.INVALID_TOKEN,
+        `First argument to ${this.tokenInfo.verifyApiName} must be a string.`,
+      );
+    }
+
+    await this.ensureProjectId();
+    const decoded = await this.decodeAndVerify(jwtToken);
+    const decodedIdToken = decoded.payload as FpnvToken;
+    decodedIdToken.getPhoneNumber = () => decodedIdToken.sub;
+    return decodedIdToken;
+  }
+
+  private async ensureProjectId(): Promise<string> {
+    const projectId = await util.findProjectId(this.app);
+    if (!validator.isNonEmptyString(projectId)) {
+      throw new FirebaseFpnvError(
+        FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT,
+        'Must initialize app with a cert credential or set your Firebase project ID as the ' +
+        `GOOGLE_CLOUD_PROJECT environment variable to call ${this.tokenInfo.verifyApiName}.`);
+    }
+    return projectId;
+  }
+
+  private async decodeAndVerify(
+    token: string,
+  ): Promise<DecodedToken> {
+    const decodedToken = await this.safeDecode(token);
+    this.verifyContent(decodedToken);
+    await this.verifySignature(token);
+    return decodedToken;
+  }
+
+  private async safeDecode(jwtToken: string): Promise<DecodedToken> {
+    try {
+      return await decodeJwt(jwtToken);
+    } catch (err) {
+      if (err.code === JwtErrorCode.INVALID_ARGUMENT) {
+        const verifyJwtTokenDocsMessage = ` See ${this.tokenInfo.url} ` +
+          `for details on how to retrieve ${this.shortNameArticle} ${this.tokenInfo.shortName}.`;
+        const errorMessage = `Decoding ${this.tokenInfo.jwtName} failed. Make sure you passed ` +
+          `the entire string JWT which represents ${this.shortNameArticle} ` +
+          `${this.tokenInfo.shortName}.` + verifyJwtTokenDocsMessage;
+        throw new FirebaseFpnvError(FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT,
+          errorMessage);
+      }
+      throw new FirebaseFpnvError(FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT, err.message);
+    }
+  }
+
+  private verifyContent(
+    fullDecodedToken: DecodedToken,
+  ): void {
+    const header = fullDecodedToken && fullDecodedToken.header;
+    const payload = fullDecodedToken && fullDecodedToken.payload;
+
+    const projectIdMatchMessage = ` Make sure the ${this.tokenInfo.shortName} comes from the same ` +
+      'Firebase project as the service account used to authenticate this SDK.';
+    const verifyJwtTokenDocsMessage = ` See ${this.tokenInfo.url} ` +
+      `for details on how to retrieve ${this.shortNameArticle} ${this.tokenInfo.shortName}.`;
+
+    let errorMessage: string | undefined;
+
+    // JWT Header
+    if (typeof header.kid === 'undefined') {
+      errorMessage = `${this.tokenInfo.jwtName} has no "kid" claim.`;
+      errorMessage += verifyJwtTokenDocsMessage;
+    } else if (header.alg !== ALGORITHM_ES256) {
+      errorMessage = `${this.tokenInfo.jwtName} has incorrect algorithm. Expected ` +
+        `"${ALGORITHM_ES256}" but got "${header.alg}". ${verifyJwtTokenDocsMessage}`;
+    } else if (header.typ !== this.tokenInfo.typ) {
+      errorMessage = `${this.tokenInfo.jwtName} has incorrect typ. Expected "${this.tokenInfo.typ}" but got ` +
+        `"${header.typ}". ${verifyJwtTokenDocsMessage}`;
+    }
+    // FPNV Token
+    else if (!validator.isNonEmptyString(payload.iss)) {
+      errorMessage = `${this.tokenInfo.jwtName} has incorrect "iss" (issuer) claim. Expected ` +
+        `an issuer starting with "${this.issuer}" but got "${payload.iss}".`
+        + ` ${projectIdMatchMessage} ${verifyJwtTokenDocsMessage}`;
+    } else if (!validator.isNonEmptyArray(payload.aud) || !payload.aud.includes(payload.iss)) {
+      errorMessage = `${this.tokenInfo.jwtName} has incorrect "aud" (audience) claim. Expected ` +
+        `"${payload.iss}" to be one of "${payload.aud}". ${projectIdMatchMessage} ${verifyJwtTokenDocsMessage}`;
+    } else if (typeof payload.sub !== 'string') {
+      errorMessage = `${this.tokenInfo.jwtName} has no "sub" (subject) claim. ${verifyJwtTokenDocsMessage}`;
+    } else if (payload.sub === '') {
+      errorMessage = `${this.tokenInfo.jwtName} has an empty "sub" (subject) claim. ${verifyJwtTokenDocsMessage}`;
+    }
+
+    if (errorMessage) {
+      throw new FirebaseFpnvError(FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT, errorMessage);
+    }
+  }
+
+  private async verifySignature(jwtToken: string): Promise<void> {
+    try {
+      return await this.signatureVerifier.verify(jwtToken);
+    } catch (error) {
+      throw this.mapJwtErrorToAuthError(error);
+    }
+  }
+
+  private mapJwtErrorToAuthError(error: JwtError): Error {
+    const verifyJwtTokenDocsMessage = ` See ${this.tokenInfo.url} ` +
+      `for details on how to retrieve ${this.shortNameArticle} ${this.tokenInfo.shortName}.`;
+    if (error.code === JwtErrorCode.TOKEN_EXPIRED) {
+      const errorMessage = `${this.tokenInfo.jwtName} has expired. Get a fresh ${this.tokenInfo.shortName}` +
+        ` from your client app and try again. ${verifyJwtTokenDocsMessage}`;
+      return new FirebaseFpnvError(FPNV_ERROR_CODE_MAPPING.EXPIRED_TOKEN, errorMessage);
+    } else if (error.code === JwtErrorCode.INVALID_SIGNATURE) {
+      const errorMessage = `${this.tokenInfo.jwtName} has invalid signature. ${verifyJwtTokenDocsMessage}`;
+      return new FirebaseFpnvError(FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT, errorMessage);
+    } else if (error.code === JwtErrorCode.NO_MATCHING_KID) {
+      const errorMessage = `${this.tokenInfo.jwtName} has "kid" claim which does not ` +
+        `correspond to a known public key. Most likely the ${this.tokenInfo.shortName} ` +
+        'is expired, so get a fresh token from your client app and try again.';
+      return new FirebaseFpnvError(FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT, errorMessage);
+    }
+    return new FirebaseFpnvError(FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT, error.message);
+  }
+}
diff --git a/src/utils/jwt.ts b/src/utils/jwt.ts
index 9a66494482..41433c4f06 100644
--- a/src/utils/jwt.ts
+++ b/src/utils/jwt.ts
@@ -21,6 +21,7 @@ import { HttpClient, HttpRequestConfig, RequestResponseError } from '../utils/ap
 import { Agent } from 'http';
 
 export const ALGORITHM_RS256: jwt.Algorithm = 'RS256' as const;
+export const ALGORITHM_ES256: jwt.Algorithm = 'ES256' as const;
 
 // `jsonwebtoken` converts errors from the `getKey` callback to its own `JsonWebTokenError` type
 // and prefixes the error message with the following. Use the prefix to identify errors thrown
@@ -201,7 +202,8 @@ export class PublicKeySignatureVerifier implements SignatureVerifier {
         'The provided token must be a string.'));
     }
 
-    return verifyJwtSignature(token, getKeyCallback(this.keyFetcher), { algorithms: [ALGORITHM_RS256] })
+    return verifyJwtSignature(token, getKeyCallback(this.keyFetcher), 
+      { algorithms: [ALGORITHM_RS256, ALGORITHM_ES256] })
       .catch((error: JwtError) => {
         if (error.code === JwtErrorCode.NO_KID_IN_HEADER) {
           // No kid in JWT header. Try with all the public keys.
diff --git a/test/unit/fpnv/fpnv-api-client-internal.spec.ts b/test/unit/fpnv/fpnv-api-client-internal.spec.ts
new file mode 100644
index 0000000000..db639cb47d
--- /dev/null
+++ b/test/unit/fpnv/fpnv-api-client-internal.spec.ts
@@ -0,0 +1,85 @@
+/*!
+ * @license
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+import { expect } from 'chai';
+import {
+  FirebaseFpnvError,
+  JWKS_URL,
+  PN_TOKEN_INFO,
+  FPNV_ERROR_CODE_MAPPING
+} from '../../../src/fpnv/fpnv-api-client-internal';
+import { PrefixedFirebaseError, FirebaseError } from '../../../src/utils/error';
+
+const FPNV_PREFIX = 'fpnv';
+
+describe('FPNV Constants and Error Class', () => {
+
+  describe('Constants Integrity', () => {
+    it('should have the correct CLIENT_CERT_URL', () => {
+      expect(JWKS_URL).to.equal('https://fpnv.googleapis.com/v1beta/jwks');
+    });
+
+    it('should have the correct structure and values for PN_TOKEN_INFO', () => {
+      expect(PN_TOKEN_INFO).to.be.an('object');
+      expect(PN_TOKEN_INFO).to.have.all.keys('url', 'verifyApiName', 'jwtName', 'shortName', 'typ');
+      expect(PN_TOKEN_INFO.shortName).to.equal('FPNV token');
+      expect(PN_TOKEN_INFO.typ).to.equal('JWT');
+    });
+
+    it('should have the correct structure and values for FPNV_ERROR_CODE_MAPPING', () => {
+      expect(FPNV_ERROR_CODE_MAPPING).to.be.an('object');
+      expect(FPNV_ERROR_CODE_MAPPING).to.deep.equal({
+        INVALID_ARGUMENT: 'invalid-argument',
+        INVALID_TOKEN: 'invalid-token',
+        EXPIRED_TOKEN: 'expired-token',
+      });
+    });
+  });
+
+  describe('FirebaseFpnvError', () => {
+    const testCode = FPNV_ERROR_CODE_MAPPING.INVALID_TOKEN;
+    const testMessage = 'The provided token is malformed or invalid.';
+
+    it('should correctly extend PrefixedFirebaseError', () => {
+      const error = new FirebaseFpnvError(testCode, testMessage);
+
+      expect(error).to.be.an.instanceOf(FirebaseFpnvError);
+      expect(error).to.be.an.instanceOf(PrefixedFirebaseError);
+      expect(error).to.be.an.instanceOf(FirebaseError);
+      expect(error).to.be.an.instanceOf(Error);
+    });
+
+
+    it('should have the correct error properties on the instance', () => {
+      const error = new FirebaseFpnvError(testCode, testMessage);
+
+      expect(error.code).to.equal(`${FPNV_PREFIX}/${testCode}`);
+      expect(error.message).to.equal(testMessage);
+    });
+
+    it('should handle all defined error codes', () => {
+      const codes = Object.values(FPNV_ERROR_CODE_MAPPING);
+
+      codes.forEach(code => {
+        const error = new FirebaseFpnvError(code, `Test message for ${code}`);
+        expect(error.code).to.equal(`${FPNV_PREFIX}/${code}`);
+      });
+    });
+  });
+});
diff --git a/test/unit/fpnv/fpnv-api.spec.ts b/test/unit/fpnv/fpnv-api.spec.ts
new file mode 100644
index 0000000000..0779eba069
--- /dev/null
+++ b/test/unit/fpnv/fpnv-api.spec.ts
@@ -0,0 +1,101 @@
+/*!
+ * @license
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+import { expect } from 'chai';
+import { FpnvToken } from '../../../src/fpnv/fpnv-api';
+
+describe('FpnvToken Interface Compliance', () => {
+
+  // A helper to create a valid Mock implementation of the FpnvToken interface.
+  // In a real scenario, this object would be returned by the SDK's verify method.
+  const createMockToken = (overrides: Partial<FpnvToken> = {}): FpnvToken => {
+    const defaultToken: FpnvToken = {
+      iss: 'https://fpnv.googleapis.com/projects/1234567890',
+      aud: ['1234567890', 'my-project-id'],
+      exp: Math.floor(Date.now() / 1000) + 3600, // Expires in 1 hour
+      iat: Math.floor(Date.now() / 1000),        // Issued now
+      sub: '+15555550100',                       // Phone number
+      jti: 'unique-token-id-123',
+      nonce: 'random-nonce-string',
+
+      // Implementation of the convenience method per JSDoc
+      getPhoneNumber() {
+        return this.sub;
+      },
+
+      // Arbitrary claims
+      custom_claim: true
+    };
+
+    return { ...defaultToken, ...overrides };
+  };
+
+  describe('Structure and Claims', () => {
+    it('should have a valid issuer (iss) URL format', () => {
+      const token = createMockToken({ iss: 'https://fpnv.googleapis.com/1234567890' });
+      expect(token.iss).to.match(/^https:\/\/fpnv\.googleapis\.com\/\d+$/);
+    });
+
+    it('should have an audience (aud) containing project number and project ID', () => {
+      const projectNumber = '1234567890';
+      const projectId = 'my-project-id';
+      const token = createMockToken({ aud: [projectNumber, projectId] });
+
+      expect(token.aud).to.be.an('array').that.has.lengthOf(2);
+      expect(token.aud).to.include(projectNumber);
+      expect(token.aud).to.include(projectId);
+    });
+
+    it('should have an expiration time (exp) after the issued-at time (iat)', () => {
+      const token = createMockToken();
+      expect(token.exp).to.be.greaterThan(token.iat);
+    });
+  });
+
+  describe('getPhoneNumber()', () => {
+    it('should be a function', () => {
+      const token = createMockToken();
+      expect(token.getPhoneNumber).to.be.a('function');
+    });
+
+    it('should return the value of the "sub" property', () => {
+      const phoneNumber = '+15550009999';
+      const token = createMockToken({ sub: phoneNumber });
+
+      const result = token.getPhoneNumber();
+
+      expect(result).to.equal(phoneNumber);
+      expect(result).to.equal(token.sub);
+    });
+
+    it('should handle cases where sub is empty string (if valid in your context)', () => {
+      const token = createMockToken({ sub: '' });
+      expect(token.getPhoneNumber()).to.equal('');
+    });
+  });
+
+  describe('Arbitrary Claims', () => {
+    it('should allow accessing custom claims via index signature', () => {
+      const token = createMockToken({ isAdmin: true, tier: 'gold' });
+
+      expect(token['isAdmin']).to.be.true;
+      expect(token['tier']).to.equal('gold');
+    });
+  });
+});
diff --git a/test/unit/fpnv/fpnv.spec.ts b/test/unit/fpnv/fpnv.spec.ts
new file mode 100644
index 0000000000..e986f5075e
--- /dev/null
+++ b/test/unit/fpnv/fpnv.spec.ts
@@ -0,0 +1,103 @@
+/*!
+ * @license
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+import { expect } from 'chai';
+import * as sinon from 'sinon';
+
+import { App } from '../../../src/app/index';
+import * as mocks from '../../resources/mocks';
+import { Fpnv } from '../../../src/fpnv/fpnv';
+import { FirebasePhoneNumberTokenVerifier } from '../../../src/fpnv/token-verifier';
+import { FpnvToken } from '../../../src/fpnv/fpnv-api';
+
+describe('Fpnv Service', () => {
+  let fpnvService: Fpnv;
+  let mockApp: App;
+  let verifyJwtStub: sinon.SinonStub;
+
+  beforeEach(() => {
+    mockApp = mocks.app();
+    verifyJwtStub = sinon.stub(FirebasePhoneNumberTokenVerifier.prototype, 'verifyJWT');
+
+    fpnvService = new Fpnv(mockApp);
+  });
+
+  afterEach(() => {
+
+    sinon.restore();
+  });
+
+  describe('Constructor', () => {
+    it('should be an instance of Fpnv', () => {
+      expect(fpnvService).to.be.instanceOf(Fpnv);
+    });
+  });
+
+  describe('get app()', () => {
+    it('should return the app instance provided in the constructor', () => {
+      expect(fpnvService.app).to.equal(mockApp);
+    });
+  });
+
+  describe('verifyToken()', () => {
+    const mockTokenString = 'eyJh...mock.jwt...token';
+    const mockDecodedToken: FpnvToken = {
+      iss: 'https://fpnv.googleapis.com/projects/1234567890',
+      aud: ['1234567890', 'my-project-id'],
+      exp: Math.floor(Date.now() / 1000) + 3600, // Expires in 1 hour
+      iat: Math.floor(Date.now() / 1000),        // Issued now
+      sub: '+15555550100',                       // Phone number
+      jti: 'unique-token-id-123',
+      nonce: 'random-nonce-string',
+      getPhoneNumber() {
+        return this.sub;
+      },
+    };
+
+    it('should call the internal verifier with the provided JWT string', async () => {
+      verifyJwtStub.resolves(mockDecodedToken);
+
+      await fpnvService.verifyToken(mockTokenString);
+
+      expect(verifyJwtStub.calledOnce).to.be.true;
+      expect(verifyJwtStub.calledWith(mockTokenString)).to.be.true;
+    });
+
+    it('should return the decoded token object on success', async () => {
+      verifyJwtStub.resolves(mockDecodedToken);
+
+      const result = await fpnvService.verifyToken(mockTokenString);
+
+      expect(result).to.equal(mockDecodedToken);
+    });
+
+    it('should bubble up errors if the verifier fails', async () => {
+      const mockError = new Error('Token expired');
+      verifyJwtStub.rejects(mockError);
+
+      try {
+        await fpnvService.verifyToken(mockTokenString);
+        // If we reach here, the test failed
+        expect.fail('Should have thrown an error');
+      } catch (error) {
+        expect(error).to.equal(mockError);
+      }
+    });
+  });
+});
diff --git a/test/unit/fpnv/index.spec.ts b/test/unit/fpnv/index.spec.ts
new file mode 100644
index 0000000000..484ed82b84
--- /dev/null
+++ b/test/unit/fpnv/index.spec.ts
@@ -0,0 +1,68 @@
+/*!
+ * @license
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+import * as chai from 'chai';
+import * as sinonChai from 'sinon-chai';
+import * as chaiAsPromised from 'chai-as-promised';
+
+import * as mocks from '../../resources/mocks';
+import { App } from '../../../src/app/index';
+import { getFirebasePnv, Fpnv } from '../../../src/fpnv/index';
+
+chai.should();
+chai.use(sinonChai);
+chai.use(chaiAsPromised);
+
+const expect = chai.expect;
+
+describe('Fpnv', () => {
+  let mockApp: App;
+  let mockCredentialApp: App;
+
+  beforeEach(() => {
+    mockApp = mocks.app();
+    mockCredentialApp = mocks.mockCredentialApp();
+  });
+
+  describe('getFirebasePnv()', () => {
+    it('should throw when default app is not available', () => {
+      expect(() => {
+        return getFirebasePnv();
+      }).to.throw('The default Firebase app does not exist.');
+    });
+
+    it('should not throw given a valid app', () => {
+      expect(() => {
+        return getFirebasePnv(mockApp);
+      }).not.to.throw();
+    });
+
+    it('should return the same instance for app instance', () => {
+      const fpnvFirst: Fpnv = getFirebasePnv(mockApp);
+      const fpnvSecond: Fpnv = getFirebasePnv(mockApp);
+      expect(fpnvFirst).to.equal(fpnvSecond);
+    });
+
+    it('should not return the same instance when different app are provided', () => {
+      const fpnvFirst: Fpnv = getFirebasePnv(mockApp);
+      const fpnvSecond: Fpnv = getFirebasePnv(mockCredentialApp);
+      expect(fpnvFirst).to.not.equal(fpnvSecond);
+    });
+  });
+});
diff --git a/test/unit/fpnv/token-verifier.spec.ts b/test/unit/fpnv/token-verifier.spec.ts
new file mode 100644
index 0000000000..4786164a1b
--- /dev/null
+++ b/test/unit/fpnv/token-verifier.spec.ts
@@ -0,0 +1,255 @@
+/*!
+ * @license
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+import * as chai from 'chai';
+import * as chaiAsPromised from 'chai-as-promised';
+import * as sinon from 'sinon';
+
+import { App } from '../../../src/app/index';
+import * as jwt from '../../../src/utils/jwt';
+import * as util from '../../../src/utils/index';
+import { FirebasePhoneNumberTokenVerifier } from '../../../src/fpnv/token-verifier';
+import { FirebasePhoneNumberTokenInfo, FPNV_ERROR_CODE_MAPPING } from '../../../src/fpnv/fpnv-api-client-internal';
+import * as mocks from '../../resources/mocks';
+
+chai.use(chaiAsPromised);
+const expect = chai.expect;
+
+describe('FirebasePhoneNumberTokenVerifier', () => {
+  let verifier: FirebasePhoneNumberTokenVerifier;
+  let mockApp: App;
+
+  let findProjectIdStub: sinon.SinonStub;
+  let decodeJwtStub: sinon.SinonStub;
+  let signatureVerifierStub: { verify: sinon.SinonStub };
+  let withJwksUrlStub: sinon.SinonStub;
+
+  const MOCK_CERT_URL = 'https://fpnv.googleapis.com/v1-beta/jwks';
+  const MOCK_ISSUER = 'https://fpnv.googleapis.com/projects/';
+  const MOCK_PROJECT_NUMBER = '123456789012';
+  const MOCK_PROJECT_ID = 'fpnv-team-test';
+  const MOCK_FPNV_PREFIX = 'fpnv';
+
+
+  const MOCK_TOKEN_INFO: FirebasePhoneNumberTokenInfo = {
+    url: 'https://firebase.google.com/docs/phone-number-verification',
+    verifyApiName: 'verifyToken()',
+    jwtName: 'Firebase Phone Verification token',
+    shortName: 'FPNV token',
+    typ: 'JWT',
+  };
+
+  const VALID_HEADER = {
+    kid: 'mock-key-id',
+    alg: 'ES256',
+    typ: 'JWT', // Matches MOCK_TOKEN_INFO.typ
+  };
+
+  const VALID_PAYLOAD = {
+    iss: MOCK_ISSUER + MOCK_PROJECT_NUMBER,
+    aud: [MOCK_ISSUER + MOCK_PROJECT_NUMBER, MOCK_ISSUER + MOCK_PROJECT_ID],
+    sub: '+15555550100',
+    exp: Math.floor(Date.now() / 1000) + 3600, // Expires in 1 hour
+    iat: Math.floor(Date.now() / 1000),        // Issued now
+  };
+
+  beforeEach(() => {
+    mockApp = mocks.app();
+    findProjectIdStub = sinon.stub(util, 'findProjectId').resolves(MOCK_PROJECT_ID);
+    decodeJwtStub = sinon.stub(jwt, 'decodeJwt');
+    signatureVerifierStub = { verify: sinon.stub().resolves() };
+    withJwksUrlStub = sinon.stub(jwt.PublicKeySignatureVerifier, 'withJwksUrl')
+      .returns(signatureVerifierStub as any);
+  });
+
+  afterEach(() => {
+    sinon.restore();
+  });
+
+  /**
+   * Helper to instantiate the verifier with default valid args
+   */
+  function createVerifier(overrides: Partial<any> = {}): FirebasePhoneNumberTokenVerifier {
+    return new FirebasePhoneNumberTokenVerifier(
+      overrides.clientCertUrl || MOCK_CERT_URL,
+      overrides.issuer || MOCK_ISSUER,
+      overrides.tokenInfo || MOCK_TOKEN_INFO,
+      mockApp
+    );
+  }
+
+  describe('Constructor', () => {
+    it('should instantiate successfully with valid arguments', () => {
+      const v = createVerifier();
+      expect(v).to.be.instanceOf(FirebasePhoneNumberTokenVerifier);
+      expect(withJwksUrlStub.calledOnce).to.be.true;
+    });
+
+    it('should throw if clientCertUrl is invalid', () => {
+      expect(() => createVerifier({ clientCertUrl: 'not-a-url' }))
+        .to.throw('invalid URL');
+    });
+
+    it('should throw if issuer is invalid', () => {
+      expect(() => createVerifier({ issuer: 'not-a-url' }))
+        .to.throw('invalid URL');
+    });
+
+    it('should throw if tokenInfo is missing required fields', () => {
+      const invalidInfo = { ...MOCK_TOKEN_INFO, verifyApiName: '' };
+      expect(() => createVerifier({ tokenInfo: invalidInfo }))
+        .to.throw('verify API name must be a non-empty string');
+    });
+  });
+
+  describe('verifyJWT()', () => {
+    beforeEach(() => {
+      verifier = createVerifier();
+    });
+
+    it('should throw if jwtToken is not a string', async () => {
+      await expect(verifier.verifyJWT(123 as any))
+        .to.be.rejectedWith('First argument to verifyToken() must be a string.');
+    });
+
+    it('should throw if project ID cannot be determined', async () => {
+      findProjectIdStub.resolves(null);
+      await expect(verifier.verifyJWT('token'))
+        .to.be.rejectedWith('Must initialize app with a cert credential or set your' +
+          ' Firebase project ID as the GOOGLE_CLOUD_PROJECT environment variable to call verifyToken().');
+    });
+
+    describe('Token Decoding', () => {
+      it('should throw if decodeJwt fails with invalid argument', async () => {
+        const err = new Error('Invalid token');
+        (err as any).code = jwt.JwtErrorCode.INVALID_ARGUMENT;
+        decodeJwtStub.rejects(err);
+
+        await expect(verifier.verifyJWT('bad-token'))
+          .to.be.rejectedWith(/Decoding Firebase Phone Verification token failed/);
+      });
+
+      it('should rethrow unknown errors from decodeJwt', async () => {
+        decodeJwtStub.rejects(new Error('Unknown error'));
+        await expect(verifier.verifyJWT('token'))
+          .to.be.rejectedWith('Unknown error');
+      });
+    });
+
+    describe('Content Verification', () => {
+      // Helper to setup a successful decode
+      const setupDecode = (headerOverrides = {}, payloadOverrides = {}): void => {
+        decodeJwtStub.resolves({
+          header: { ...VALID_HEADER, ...headerOverrides },
+          payload: { ...VALID_PAYLOAD, ...payloadOverrides },
+        });
+      };
+
+      it('should throw if "kid" is missing', async () => {
+        setupDecode({ kid: undefined });
+        await expect(verifier.verifyJWT('token')).to.be.rejectedWith('has no "kid" claim');
+      });
+
+      it('should throw if algorithm is not ES256', async () => {
+        setupDecode({ alg: 'RS256' });
+        await expect(verifier.verifyJWT('token')).to.be.rejectedWith('incorrect algorithm');
+      });
+
+      it('should throw if "typ" is incorrect', async () => {
+        setupDecode({ typ: 'WRONG' });
+        await expect(verifier.verifyJWT('token')).to.be.rejectedWith('incorrect typ');
+      });
+
+      it('should throw if "aud" does not contain issuer+projectId', async () => {
+        setupDecode({}, { aud: ['wrong-audience'] });
+        await expect(verifier.verifyJWT('token')).to.be.rejectedWith('incorrect "aud"');
+      });
+
+      it('should throw if "sub" is missing', async () => {
+        setupDecode({}, { sub: undefined });
+        await expect(verifier.verifyJWT('token')).to.be.rejectedWith('no "sub"');
+      });
+
+      it('should throw if "sub" is empty', async () => {
+        setupDecode({}, { sub: '' });
+        await expect(verifier.verifyJWT('token')).to.be.rejectedWith('empty "sub"');
+      });
+    });
+
+    describe('Signature Verification', () => {
+      beforeEach(() => {
+        // Assume decoding passes for these tests
+        decodeJwtStub.resolves({ header: VALID_HEADER, payload: VALID_PAYLOAD });
+      });
+
+      it('should call signatureVerifier.verify with the token', async () => {
+        const token = 'valid.jwt.string';
+        await verifier.verifyJWT(token);
+        expect(signatureVerifierStub.verify.calledWith(token)).to.be.true;
+      });
+
+      it('should throw EXPIRED_TOKEN if signature verifier throws TOKEN_EXPIRED', async () => {
+        const error = new Error('Expired');
+        (error as any).code = jwt.JwtErrorCode.TOKEN_EXPIRED;
+        signatureVerifierStub.verify.rejects(error);
+
+        await expect(verifier.verifyJWT('token'))
+          .to.be.rejectedWith(/has expired/)
+          .and.eventually.have.property('code', `${MOCK_FPNV_PREFIX}/${FPNV_ERROR_CODE_MAPPING.EXPIRED_TOKEN}`);
+      });
+
+      it('should throw INVALID_ARGUMENT if signature verifier throws INVALID_SIGNATURE', async () => {
+        const error = new Error('Bad Sig');
+        (error as any).code = jwt.JwtErrorCode.INVALID_SIGNATURE;
+        signatureVerifierStub.verify.rejects(error);
+
+        await expect(verifier.verifyJWT('token'))
+          .to.be.rejectedWith(/invalid signature/)
+          .and.eventually.have.property('code',`${MOCK_FPNV_PREFIX}/${FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT}`);
+      });
+
+      it('should throw INVALID_ARGUMENT if signature verifier throws NO_MATCHING_KID', async () => {
+        const error = new Error('No Key');
+        (error as any).code = jwt.JwtErrorCode.NO_MATCHING_KID;
+        signatureVerifierStub.verify.rejects(error);
+
+        await expect(verifier.verifyJWT('token'))
+          .to.be.rejectedWith(/does not correspond to a known public key/)
+          .and.eventually.have.property('code',`${MOCK_FPNV_PREFIX}/${FPNV_ERROR_CODE_MAPPING.INVALID_ARGUMENT}`);
+      });
+    });
+
+    describe('Success', () => {
+      it('should return the token with getPhoneNumber() method appended', async () => {
+        decodeJwtStub.resolves({ header: VALID_HEADER, payload: VALID_PAYLOAD });
+        signatureVerifierStub.verify.resolves();
+
+        const result = await verifier.verifyJWT('valid-token');
+
+        // Check data integrity
+        expect(result.sub).to.equal(VALID_PAYLOAD.sub);
+        expect(result.aud).to.deep.equal(VALID_PAYLOAD.aud);
+
+        // Check the dynamic method addition
+        expect(result).to.have.property('getPhoneNumber');
+        expect(result.getPhoneNumber()).to.equal(VALID_PAYLOAD.sub);
+      });
+    });
+  });
+});
diff --git a/test/unit/index.spec.ts b/test/unit/index.spec.ts
index 39ae51fd9f..826336b8bd 100644
--- a/test/unit/index.spec.ts
+++ b/test/unit/index.spec.ts
@@ -123,3 +123,10 @@ import './data-connect/index.spec';
 import './data-connect/data-connect-api-client-internal.spec';
 import './data-connect/data-connect.spec';
 import './data-connect/validate-admin-args.spec';
+
+// Fpnv
+import './fpnv/index.spec';
+import './fpnv/fpnv-api-client-internal.spec';
+import './fpnv/fpnv-api.spec';
+import './fpnv/fpnv.spec';
+import './fpnv/token-verifier.spec'