Add trackingToken to Device request object

This adds the optional trackingToken field to the Device request
object for explicit device linking via the Device Tracking Add-on.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: oschwald

CHANGELOG.md

@@ -1,6 +1,14 @@
 CHANGELOG
 =========
 
+4.2.0
+------------------
+
+* Added `trackingToken` to the `Device` request object. This is the token
+  generated by the
+  [Device Tracking Add-on](https://dev.maxmind.com/minfraud/track-devices)
+  for explicit device linking.
+
 4.1.0 (2026-01-20)
 ------------------
 

README.md

@@ -144,6 +144,7 @@ Transaction request = new Transaction.Builder(
             .acceptLanguage("en-US")
             .sessionAge(3600.6)
             .sessionId("foobar")
+            .trackingToken("abc123")
             .userAgent("Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.90 Safari/537.36")
             .build()
     ).account(

src/main/java/com/maxmind/minfraud/request/Device.java

@@ -13,13 +13,15 @@ public final class Device extends AbstractModel {
     private final String acceptLanguage;
     private final Double sessionAge;
     private final String sessionId;
+    private final String trackingToken;
 
     private Device(Device.Builder builder) {
         ipAddress = builder.ipAddress;
         userAgent = builder.userAgent;
         acceptLanguage = builder.acceptLanguage;
         sessionAge = builder.sessionAge;
         sessionId = builder.sessionId;
+        trackingToken = builder.trackingToken;
     }
 
     /**
@@ -32,6 +34,7 @@ public static final class Builder {
         String acceptLanguage;
         Double sessionAge;
         String sessionId;
+        String trackingToken;
 
         /**
          * Constructor for the {@code Device.Builder} class
@@ -100,6 +103,16 @@ public Device.Builder sessionId(String sessionId) {
             return this;
         }
 
+        /**
+         * @param val The tracking token generated by the Device Tracking Add-on
+         *            for explicit device linking.
+         * @return The builder object.
+         */
+        public Device.Builder trackingToken(String val) {
+            trackingToken = val;
+            return this;
+        }
+
         /**
          * @return An instance of {@code Device} created from the fields set on this builder.
          */
@@ -140,6 +153,14 @@ public String sessionId() {
         return sessionId;
     }
 
+    /**
+     * @return The tracking token.
+     */
+    @JsonProperty("tracking_token")
+    public String trackingToken() {
+        return trackingToken;
+    }
+
     /**
      * @return The IP address used in the transaction.
      */

src/test/java/com/maxmind/minfraud/request/DeviceTest.java

@@ -61,4 +61,11 @@ public void testSessionId() {
         var device = new Builder(ip).sessionId(id).build();
         assertEquals(id, device.sessionId());
     }
+
+    @Test
+    public void testTrackingToken() {
+        var token = "abc123";
+        var device = new Builder(ip).trackingToken(token).build();
+        assertEquals(token, device.trackingToken());
+    }
 }