Working with JSON Web Tokens (JWT)

JSON Web Tokens are a commonly used industry standard for securely transferring information as a JSON object. When using the Google Wallet API, you encode the details of the Passes Object you want to use to create a pass instance in JWT (pronounced "jot") format, then send that JWT in a request to the Google Wallet API.

JWTs are kept secure by signing them with a shared secret before they are sent to the Google Wallet API. If you are using the Google Wallet REST API, the signing secret is your Google Cloud service account key. If you are using the Google Wallet Android SDK, the signing secret is the SHA-1 fingerprint for your Android app.

Encode a pass in a JWT

When the LoyaltyObject is created, wrap it with an unsigned JWT with the payload.LoyaltyObjects attribute, as shown in the following snippet:

JSON

{
  "iss": "OWNER_EMAIL_ADDRESS",
  "aud": "google",
  "typ": "savetowallet",
  "iat": "UNIX_TIME",
  "origins": [],
  "payload": {
      "loyaltyObjects": [ NEW_OBJECT ]
  }
}

For more information on the expected format of JWTs, see the JWT reference.

Sign a JWT

JWTs are kept secure by signing them with a shared secret before they are sent to the Google Wallet API. If you are using the Google Wallet REST API, the signing secret is your Google Cloud service account key. If you are using the Google Wallet Android SDK, the signing secret is the SHA-1 fingerprint for your Android app.

Web, email, and SMS

The JWT must be signed using the service account key associated with the Google Cloud service account you authorized in the Google Wallet Business Console. The Google Wallet API will validate these claims by verifying the JWT signature.

Signing the JWT will produce a token that can then be used to create an 'Add to Google Wallet' link that can be used to issue the pass to a user:

Java

To start your integration in Java, refer to our complete code samples on GitHub.

/**
 * Generate a signed JWT that creates a new pass class and object.
 *
 * <p>When the user opens the "Add to Google Wallet" URL and saves the pass to their wallet, the
 * pass class and object defined in the JWT are created. This allows you to create multiple pass
 * classes and objects in one API call when the user saves the pass to their wallet.
 *
 * @param issuerId The issuer ID being used for this request.
 * @param classSuffix Developer-defined unique ID for this pass class.
 * @param objectSuffix Developer-defined unique ID for the pass object.
 * @return An "Add to Google Wallet" link.
 */
public String createJWTNewObjects(String issuerId, String classSuffix, String objectSuffix) {
  // See link below for more information on required properties
  // https://developers.google.com/wallet/retail/loyalty-cards/rest/v1/loyaltyclass
  LoyaltyClass newClass =
      new LoyaltyClass()
          .setId(String.format("%s.%s", issuerId, classSuffix))
          .setIssuerName("Issuer name")
          .setReviewStatus("UNDER_REVIEW")
          .setProgramName("Program name")
          .setProgramLogo(
              new Image()
                  .setSourceUri(
                      new ImageUri()
                          .setUri(
                              "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"))
                  .setContentDescription(
                      new LocalizedString()
                          .setDefaultValue(
                              new TranslatedString()
                                  .setLanguage("en-US")
                                  .setValue("Logo description"))));

  // See link below for more information on required properties
  // https://developers.google.com/wallet/retail/loyalty-cards/rest/v1/loyaltyobject
  LoyaltyObject newObject =
      new LoyaltyObject()
          .setId(String.format("%s.%s", issuerId, objectSuffix))
          .setClassId(String.format("%s.%s", issuerId, classSuffix))
          .setState("ACTIVE")
          .setHeroImage(
              new Image()
                  .setSourceUri(
                      new ImageUri()
                          .setUri(
                              "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"))
                  .setContentDescription(
                      new LocalizedString()
                          .setDefaultValue(
                              new TranslatedString()
                                  .setLanguage("en-US")
                                  .setValue("Hero image description"))))
          .setTextModulesData(
                  List.of(
                          new TextModuleData()
                                  .setHeader("Text module header")
                                  .setBody("Text module body")
                                  .setId("TEXT_MODULE_ID")))
          .setLinksModuleData(
              new LinksModuleData()
                  .setUris(
                      Arrays.asList(
                          new Uri()
                              .setUri("http://maps.google.com/")
                              .setDescription("Link module URI description")
                              .setId("LINK_MODULE_URI_ID"),
                          new Uri()
                              .setUri("tel:6505555555")
                              .setDescription("Link module tel description")
                              .setId("LINK_MODULE_TEL_ID"))))
          .setImageModulesData(
                  List.of(
                          new ImageModuleData()
                                  .setMainImage(
                                          new Image()
                                                  .setSourceUri(
                                                          new ImageUri()
                                                                  .setUri(
                                                                          "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"))
                                                  .setContentDescription(
                                                          new LocalizedString()
                                                                  .setDefaultValue(
                                                                          new TranslatedString()
                                                                                  .setLanguage("en-US")
                                                                                  .setValue("Image module description"))))
                                  .setId("IMAGE_MODULE_ID")))
          .setBarcode(new Barcode().setType("QR_CODE").setValue("QR code value"))
          .setLocations(
                  List.of(
                          new LatLongPoint()
                                  .setLatitude(37.424015499999996)
                                  .setLongitude(-122.09259560000001)))
          .setAccountId("Account ID")
          .setAccountName("Account name")
          .setLoyaltyPoints(
              new LoyaltyPoints()
                  .setLabel("Points")
                  .setBalance(new LoyaltyPointsBalance().setInt(800)));

  // Create the JWT as a HashMap object
  HashMap<String, Object> claims = new HashMap<String, Object>();
  claims.put("iss", ((ServiceAccountCredentials) credentials).getClientEmail());
  claims.put("aud", "google");
  claims.put("origins", List.of("www.example.com"));
  claims.put("typ", "savetowallet");

  // Create the Google Wallet payload and add to the JWT
  HashMap<String, Object> payload = new HashMap<String, Object>();
  payload.put("loyaltyClasses", List.of(newClass));
  payload.put("loyaltyObjects", List.of(newObject));
  claims.put("payload", payload);

  // The service account credentials are used to sign the JWT
  Algorithm algorithm =
      Algorithm.RSA256(
          null, (RSAPrivateKey) ((ServiceAccountCredentials) credentials).getPrivateKey());
  String token = JWT.create().withPayload(claims).sign(algorithm);

  System.out.println("Add to Google Wallet link");
  System.out.printf("https://pay.google.com/gp/v/save/%s%n", token);

  return String.format("https://pay.google.com/gp/v/save/%s", token);
}

PHP

To start your integration in PHP, refer to our complete code samples on GitHub.

/**
 * Generate a signed JWT that creates a new pass class and object.
 *
 * When the user opens the "Add to Google Wallet" URL and saves the pass to
 * their wallet, the pass class and object defined in the JWT are
 * created. This allows you to create multiple pass classes and objects in
 * one API call when the user saves the pass to their wallet.
 *
 * @param string $issuerId The issuer ID being used for this request.
 * @param string $classSuffix Developer-defined unique ID for the pass class.
 * @param string $objectSuffix Developer-defined unique ID for the pass object.
 *
 * @return string An "Add to Google Wallet" link.
 */
public function createJwtNewObjects(string $issuerId, string $classSuffix, string $objectSuffix)
{
  // See link below for more information on required properties
  // https://developers.google.com/wallet/retail/loyalty-cards/rest/v1/loyaltyclass
  $newClass = new LoyaltyClass([
    'id' => "{$issuerId}.{$classSuffix}",
    'issuerName' => 'Issuer name',
    'reviewStatus' => 'UNDER_REVIEW',
    'programName' => 'Program name',
    'programLogo' => new Image([
      'sourceUri' => new ImageUri([
        'uri' => 'http://farm8.staticflickr.com/7340/11177041185_a61a7f2139_o.jpg'
      ]),
      'contentDescription' => new LocalizedString([
        'defaultValue' => new TranslatedString([
          'language' => 'en-US',
          'value' => 'Logo description'
        ])
      ])
    ])
  ]);

  // See link below for more information on required properties
  // https://developers.google.com/wallet/retail/loyalty-cards/rest/v1/loyaltyobject
  $newObject = new LoyaltyObject([
    'id' => "{$issuerId}.{$objectSuffix}",
    'classId' => "{$issuerId}.{$classSuffix}",
    'state' => 'ACTIVE',
    'heroImage' => new Image([
      'sourceUri' => new ImageUri([
        'uri' => 'https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg'
      ]),
      'contentDescription' => new LocalizedString([
        'defaultValue' => new TranslatedString([
          'language' => 'en-US',
          'value' => 'Hero image description'
        ])
      ])
    ]),
    'textModulesData' => [
      new TextModuleData([
        'header' => 'Text module header',
        'body' => 'Text module body',
        'id' => 'TEXT_MODULE_ID'
      ])
    ],
    'linksModuleData' => new LinksModuleData([
      'uris' => [
        new Uri([
          'uri' => 'http://maps.google.com/',
          'description' => 'Link module URI description',
          'id' => 'LINK_MODULE_URI_ID'
        ]),
        new Uri([
          'uri' => 'tel:6505555555',
          'description' => 'Link module tel description',
          'id' => 'LINK_MODULE_TEL_ID'
        ])
      ]
    ]),
    'imageModulesData' => [
      new ImageModuleData([
        'mainImage' => new Image([
          'sourceUri' => new ImageUri([
            'uri' => 'http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg'
          ]),
          'contentDescription' => new LocalizedString([
            'defaultValue' => new TranslatedString([
              'language' => 'en-US',
              'value' => 'Image module description'
            ])
          ])
        ]),
        'id' => 'IMAGE_MODULE_ID'
      ])
    ],
    'barcode' => new Barcode([
      'type' => 'QR_CODE',
      'value' => 'QR code value'
    ]),
    'locations' => [
      new LatLongPoint([
        'latitude' => 37.424015499999996,
        'longitude' =>  -122.09259560000001
      ])
    ],
    'accountId' => 'Account ID',
    'accountName' => 'Account name',
    'loyaltyPoints' => new LoyaltyPoints([
      'balance' => new LoyaltyPointsBalance([
        'int' => 800
      ])
    ])
  ]);

  // The service account credentials are used to sign the JWT
  $serviceAccount = json_decode(file_get_contents($this->keyFilePath), true);

  // Create the JWT as an array of key/value pairs
  $claims = [
    'iss' => $serviceAccount['client_email'],
    'aud' => 'google',
    'origins' => ['www.example.com'],
    'typ' => 'savetowallet',
    'payload' => [
      'loyaltyClasses' => [
        $newClass
      ],
      'loyaltyObjects' => [
        $newObject
      ]
    ]
  ];

  $token = JWT::encode(
    $claims,
    $serviceAccount['private_key'],
    'RS256'
  );

  print "Add to Google Wallet link\n";
  print "https://pay.google.com/gp/v/save/{$token}";

  return "https://pay.google.com/gp/v/save/{$token}";
}

Python

To start your integration in Python, refer to our complete code samples on GitHub.

def create_jwt_new_objects(self, issuer_id: str, class_suffix: str,
                           object_suffix: str) -> str:
    """Generate a signed JWT that creates a new pass class and object.

    When the user opens the "Add to Google Wallet" URL and saves the pass to
    their wallet, the pass class and object defined in the JWT are
    created. This allows you to create multiple pass classes and objects in
    one API call when the user saves the pass to their wallet.

    Args:
        issuer_id (str): The issuer ID being used for this request.
        class_suffix (str): Developer-defined unique ID for the pass class.
        object_suffix (str): Developer-defined unique ID for the pass object.

    Returns:
        An "Add to Google Wallet" link.
    """

    # See link below for more information on required properties
    # https://developers.google.com/wallet/retail/loyalty-cards/rest/v1/loyaltyclass
    new_class = {
        'id': f'{issuer_id}.{class_suffix}',
        'issuerName': 'Issuer name',
        'reviewStatus': 'UNDER_REVIEW',
        'programName': 'Program name',
        'programLogo': {
            'sourceUri': {
                'uri':
                    'http://farm8.staticflickr.com/7340/11177041185_a61a7f2139_o.jpg'
            },
            'contentDescription': {
                'defaultValue': {
                    'language': 'en-US',
                    'value': 'Logo description'
                }
            }
        }
    }

    # See link below for more information on required properties
    # https://developers.google.com/wallet/retail/loyalty-cards/rest/v1/loyaltyobject
    new_object = {
        'id': f'{issuer_id}.{object_suffix}',
        'classId': f'{issuer_id}.{class_suffix}',
        'state': 'ACTIVE',
        'heroImage': {
            'sourceUri': {
                'uri':
                    'https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg'
            },
            'contentDescription': {
                'defaultValue': {
                    'language': 'en-US',
                    'value': 'Hero image description'
                }
            }
        },
        'textModulesData': [{
            'header': 'Text module header',
            'body': 'Text module body',
            'id': 'TEXT_MODULE_ID'
        }],
        'linksModuleData': {
            'uris': [{
                'uri': 'http://maps.google.com/',
                'description': 'Link module URI description',
                'id': 'LINK_MODULE_URI_ID'
            }, {
                'uri': 'tel:6505555555',
                'description': 'Link module tel description',
                'id': 'LINK_MODULE_TEL_ID'
            }]
        },
        'imageModulesData': [{
            'mainImage': {
                'sourceUri': {
                    'uri':
                        'http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg'
                },
                'contentDescription': {
                    'defaultValue': {
                        'language': 'en-US',
                        'value': 'Image module description'
                    }
                }
            },
            'id': 'IMAGE_MODULE_ID'
        }],
        'barcode': {
            'type': 'QR_CODE',
            'value': 'QR code'
        },
        'locations': [{
            'latitude': 37.424015499999996,
            'longitude': -122.09259560000001
        }],
        'accountId': 'Account id',
        'accountName': 'Account name',
        'loyaltyPoints': {
            'label': 'Points',
            'balance': {
                'int': 800
            }
        }
    }

    # Create the JWT claims
    claims = {
        'iss': self.credentials.service_account_email,
        'aud': 'google',
        'origins': ['www.example.com'],
        'typ': 'savetowallet',
        'payload': {
            # The listed classes and objects will be created
            'loyaltyClasses': [new_class],
            'loyaltyObjects': [new_object]
        },
    }

    # The service account credentials are used to sign the JWT
    signer = crypt.RSASigner.from_service_account_file(self.key_file_path)
    token = jwt.encode(signer, claims).decode('utf-8')

    print('Add to Google Wallet link')
    print(f'https://pay.google.com/gp/v/save/{token}')

    return f'https://pay.google.com/gp/v/save/{token}'

C#

To start your integration in C#, refer to our complete code samples on GitHub.

/// <summary>
/// Generate a signed JWT that creates a new pass class and object.
/// <para />
/// When the user opens the "Add to Google Wallet" URL and saves the pass to
/// their wallet, the pass class and object defined in the JWT are created.
/// This allows you to create multiple pass classes and objects in one API
/// call when the user saves the pass to their wallet.
/// <para />
/// The Google Wallet C# library uses Newtonsoft.Json.JsonPropertyAttribute
/// to specify the property names when converting objects to JSON. The
/// Newtonsoft.Json.JsonConvert.SerializeObject method will automatically
/// serialize the object with the right property names.
/// </summary>
/// <param name="issuerId">The issuer ID being used for this request.</param>
/// <param name="classSuffix">Developer-defined unique ID for this pass class.</param>
/// <param name="objectSuffix">Developer-defined unique ID for the pass object.</param>
/// <returns>An "Add to Google Wallet" link.</returns>
public string CreateJWTNewObjects(string issuerId, string classSuffix, string objectSuffix)
{
  // Ignore null values when serializing to/from JSON
  JsonSerializerSettings excludeNulls = new JsonSerializerSettings()
  {
    NullValueHandling = NullValueHandling.Ignore
  };

  // See link below for more information on required properties
  // https://developers.google.com/wallet/retail/loyalty-cards/rest/v1/loyaltyclass
  LoyaltyClass newClass = new LoyaltyClass
  {
    Id = $"{issuerId}.{classSuffix}",
    IssuerName = "Issuer name",
    ReviewStatus = "UNDER_REVIEW",
    ProgramName = "Program name",
    ProgramLogo = new Image
    {
      SourceUri = new ImageUri
      {
        Uri = "http://farm8.staticflickr.com/7340/11177041185_a61a7f2139_o.jpg"
      },
      ContentDescription = new LocalizedString
      {
        DefaultValue = new TranslatedString
        {
          Language = "en-US",
          Value = "Logo description"
        }
      }
    }
  };

  // See link below for more information on required properties
  // https://developers.google.com/wallet/retail/loyalty-cards/rest/v1/loyaltyobject
  LoyaltyObject newObject = new LoyaltyObject
  {
    Id = $"{issuerId}.{objectSuffix}",
    ClassId = $"{issuerId}.{classSuffix}",
    State = "ACTIVE",
    HeroImage = new Image
    {
      SourceUri = new ImageUri
      {
        Uri = "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
      },
      ContentDescription = new LocalizedString
      {
        DefaultValue = new TranslatedString
        {
          Language = "en-US",
          Value = "Hero image description"
        }
      }
    },
    TextModulesData = new List<TextModuleData>
    {
      new TextModuleData
      {
        Header = "Text module header",
        Body = "Text module body",
        Id = "TEXT_MODULE_ID"
      }
    },
    LinksModuleData = new LinksModuleData
    {
      Uris = new List<Google.Apis.Walletobjects.v1.Data.Uri>
      {
        new Google.Apis.Walletobjects.v1.Data.Uri
        {
          UriValue = "http://maps.google.com/",
          Description = "Link module URI description",
          Id = "LINK_MODULE_URI_ID"
        },
        new Google.Apis.Walletobjects.v1.Data.Uri
        {
          UriValue = "tel:6505555555",
          Description = "Link module tel description",
          Id = "LINK_MODULE_TEL_ID"
        }
      }
    },
    ImageModulesData = new List<ImageModuleData>
    {
      new ImageModuleData
      {
        MainImage = new Image
        {
          SourceUri = new ImageUri
          {
            Uri = "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
          },
          ContentDescription = new LocalizedString
          {
            DefaultValue = new TranslatedString
            {
              Language = "en-US",
              Value = "Image module description"
            }
          }
        },
        Id = "IMAGE_MODULE_ID"
      }
    },
    Barcode = new Barcode
    {
      Type = "QR_CODE",
      Value = "QR code"
    },
    Locations = new List<LatLongPoint>
    {
      new LatLongPoint
      {
        Latitude = 37.424015499999996,
        Longitude = -122.09259560000001
      }
    },
    AccountId = "Account id",
    AccountName = "Account name",
    LoyaltyPoints = new LoyaltyPoints
    {
      Label = "Points",
      Balance = new LoyaltyPointsBalance
      {
        Int__ = 800
      }
    }
  };

  // Create JSON representations of the class and object
  JObject serializedClass = JObject.Parse(
      JsonConvert.SerializeObject(newClass, excludeNulls));
  JObject serializedObject = JObject.Parse(
      JsonConvert.SerializeObject(newObject, excludeNulls));

  // Create the JWT as a JSON object
  JObject jwtPayload = JObject.Parse(JsonConvert.SerializeObject(new
  {
    iss = credentials.Id,
    aud = "google",
    origins = new List<string>
    {
      "www.example.com"
    },
    typ = "savetowallet",
    payload = JObject.Parse(JsonConvert.SerializeObject(new
    {
      // The listed classes and objects will be created
      // when the user saves the pass to their wallet
      loyaltyClasses = new List<JObject>
      {
        serializedClass
      },
      loyaltyObjects = new List<JObject>
      {
        serializedObject
      }
    }))
  }));

  // Deserialize into a JwtPayload
  JwtPayload claims = JwtPayload.Deserialize(jwtPayload.ToString());

  // The service account credentials are used to sign the JWT
  RsaSecurityKey key = new RsaSecurityKey(credentials.Key);
  SigningCredentials signingCredentials = new SigningCredentials(
      key, SecurityAlgorithms.RsaSha256);
  JwtSecurityToken jwt = new JwtSecurityToken(
      new JwtHeader(signingCredentials), claims);
  string token = new JwtSecurityTokenHandler().WriteToken(jwt);

  Console.WriteLine("Add to Google Wallet link");
  Console.WriteLine($"https://pay.google.com/gp/v/save/{token}");

  return $"https://pay.google.com/gp/v/save/{token}";
}

Node.js

To start your integration in Node, refer to our complete code samples on GitHub.

/**
 * Generate a signed JWT that creates a new pass class and object.
 *
 * When the user opens the "Add to Google Wallet" URL and saves the pass to
 * their wallet, the pass class and object defined in the JWT are
 * created. This allows you to create multiple pass classes and objects in
 * one API call when the user saves the pass to their wallet.
 *
 * @param {string} issuerId The issuer ID being used for this request.
 * @param {string} classSuffix Developer-defined unique ID for the pass class.
 * @param {string} objectSuffix Developer-defined unique ID for the pass object.
 *
 * @returns {string} An "Add to Google Wallet" link.
 */
createJwtNewObjects(issuerId, classSuffix, objectSuffix) {
  // See link below for more information on required properties
  // https://developers.google.com/wallet/retail/loyalty-cards/rest/v1/loyaltyclass
  let newClass = {
    'id': `${issuerId}.${classSuffix}`,
    'issuerName': 'Issuer name',
    'reviewStatus': 'UNDER_REVIEW',
    'programName': 'Program name',
    'programLogo': {
      'sourceUri': {
        'uri': 'http://farm8.staticflickr.com/7340/11177041185_a61a7f2139_o.jpg'
      },
      'contentDescription': {
        'defaultValue': {
          'language': 'en-US',
          'value': 'Logo description'
        }
      }
    }
  };

  // See link below for more information on required properties
  // https://developers.google.com/wallet/retail/loyalty-cards/rest/v1/loyaltyobject
  let newObject = {
    'id': `${issuerId}.${objectSuffix}`,
    'classId': `${issuerId}.${classSuffix}`,
    'state': 'ACTIVE',
    'heroImage': {
      'sourceUri': {
        'uri': 'https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg'
      },
      'contentDescription': {
        'defaultValue': {
          'language': 'en-US',
          'value': 'Hero image description'
        }
      }
    },
    'textModulesData': [
      {
        'header': 'Text module header',
        'body': 'Text module body',
        'id': 'TEXT_MODULE_ID'
      }
    ],
    'linksModuleData': {
      'uris': [
        {
          'uri': 'http://maps.google.com/',
          'description': 'Link module URI description',
          'id': 'LINK_MODULE_URI_ID'
        },
        {
          'uri': 'tel:6505555555',
          'description': 'Link module tel description',
          'id': 'LINK_MODULE_TEL_ID'
        }
      ]
    },
    'imageModulesData': [
      {
        'mainImage': {
          'sourceUri': {
            'uri': 'http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg'
          },
          'contentDescription': {
            'defaultValue': {
              'language': 'en-US',
              'value': 'Image module description'
            }
          }
        },
        'id': 'IMAGE_MODULE_ID'
      }
    ],
    'barcode': {
      'type': 'QR_CODE',
      'value': 'QR code'
    },
    'locations': [
      {
        'latitude': 37.424015499999996,
        'longitude': -122.09259560000001
      }
    ],
    'accountId': 'Account id',
    'accountName': 'Account name',
    'loyaltyPoints': {
      'label': 'Points',
      'balance': {
        'int': 800
      }
    }
  };

  // Create the JWT claims
  let claims = {
    iss: this.credentials.client_email,
    aud: 'google',
    origins: ['www.example.com'],
    typ: 'savetowallet',
    payload: {
      // The listed classes and objects will be created
      loyaltyClasses: [newClass],
      loyaltyObjects: [newObject]
    }
  };

  // The service account credentials are used to sign the JWT
  let token = jwt.sign(claims, this.credentials.private_key, { algorithm: 'RS256' });

  console.log('Add to Google Wallet link');
  console.log(`https://pay.google.com/gp/v/save/${token}`);

  return `https://pay.google.com/gp/v/save/${token}`;
}

Go

To start your integration in Go, refer to our complete code samples on GitHub code samples on Github.

// Generate a signed JWT that creates a new pass class and object.
//
// When the user opens the "Add to Google Wallet" URL and saves the pass to
// their wallet, the pass class and object defined in the JWT are
// created. This allows you to create multiple pass classes and objects in
// one API call when the user saves the pass to their wallet.
func (d *demoLoyalty) createJwtNewObjects(issuerId, classSuffix, objectSuffix string) {
	loyaltyObject := new(walletobjects.LoyaltyObject)
	loyaltyObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix+"_")
	loyaltyObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
	loyaltyObject.AccountName = "Account name"
	loyaltyObject.AccountId = "Account id"
	loyaltyObject.State = "ACTIVE"

	loyaltyJson, _ := json.Marshal(loyaltyObject)
	var payload map[string]any
	json.Unmarshal([]byte(fmt.Sprintf(`
	{
		"loyaltyObjects": [%s]
	}
	`, loyaltyJson)), &payload)
	claims := jwt.MapClaims{
		"iss":     d.credentials.Email,
		"aud":     "google",
		"origins": []string{"www.example.com"},
		"typ":     "savetowallet",
		"payload": payload,
	}

	// The service account credentials are used to sign the JWT
	key, _ := jwt.ParseRSAPrivateKeyFromPEM(d.credentials.PrivateKey)
	token, _ := jwt.NewWithClaims(jwt.SigningMethodRS256, claims).SignedString(key)

	fmt.Println("Add to Google Wallet link for new objects")
	fmt.Println("https://pay.google.com/gp/v/save/" + token)
}

Android apps

When the savePasses method is called to issue a pass to a user, the Google Wallet Android SDK automatically signs your JWT with the SHA-1 fingerprint of your app signing key that you provided in the Google Wallet Business Console. Alternatively, you may also issue the pass using a previously signed JWT using the savePassesJwt method of the Android SDK.

For more information, see Issuing passes with the Android SDK.