diff --git a/src/test/java/com/onfido/integration/AddressTest.java b/src/test/java/com/onfido/integration/AddressTest.java
index e6760e4..d646e9d 100644
--- a/src/test/java/com/onfido/integration/AddressTest.java
+++ b/src/test/java/com/onfido/integration/AddressTest.java
@@ -14,5 +14,7 @@ public void pickTest() throws Exception {
     Assertions.assertNotNull(addresses);
     Assertions.assertEquals("S2 2DF", addresses.get(0).getPostcode());
     Assertions.assertEquals("S2 2DF", addresses.get(1).getPostcode());
+
+    Assertions.assertNotNull(addresses.get(0).toJson());
   }
 }
diff --git a/src/test/java/com/onfido/integration/ApplicantTest.java b/src/test/java/com/onfido/integration/ApplicantTest.java
index 340f3c7..22aae9a 100644
--- a/src/test/java/com/onfido/integration/ApplicantTest.java
+++ b/src/test/java/com/onfido/integration/ApplicantTest.java
@@ -29,6 +29,8 @@ public void createApplicantTest() throws Exception {
 
     Assertions.assertEquals("First", applicant.getFirstName());
     Assertions.assertEquals("Last", applicant.getLastName());
+
+    Assertions.assertNotNull(applicant.toJson());
   }
 
   @Test
@@ -38,6 +40,8 @@ public void findApplicantTest() throws Exception {
 
     Assertions.assertEquals("First", lookupApplicant.getFirstName());
     Assertions.assertEquals("Last", lookupApplicant.getLastName());
+
+    Assertions.assertNotNull(lookupApplicant.toJson());
   }
 
   @Test
@@ -47,6 +51,8 @@ public void updateApplicantTest() throws Exception {
 
     Assertions.assertEquals("Updated", updatedApplicant.getFirstName());
     Assertions.assertEquals("Last", updatedApplicant.getLastName());
+
+    Assertions.assertNotNull(updatedApplicant.toJson());
   }
 
   @Test
@@ -76,5 +82,8 @@ public void listApplicants() throws Exception {
 
     Assertions.assertEquals("Applicant1", applicants.get(0).getFirstName());
     Assertions.assertEquals("Applicant2", applicants.get(1).getFirstName());
+
+    Assertions.assertNotNull(applicants.get(0).toJson());
+    Assertions.assertNotNull(applicants.get(1).toJson());
   }
 }
diff --git a/src/test/java/com/onfido/integration/CheckTest.java b/src/test/java/com/onfido/integration/CheckTest.java
index f1b0278..a34481e 100644
--- a/src/test/java/com/onfido/integration/CheckTest.java
+++ b/src/test/java/com/onfido/integration/CheckTest.java
@@ -33,6 +33,8 @@ public void createCheckTest() throws Exception {
 
     Assertions.assertEquals(applicant.getId(), check.getApplicantId());
     Assertions.assertEquals(null, check.getWebhookIds());
+
+    Assertions.assertNotNull(check.toJson());
   }
 
   @Test
@@ -85,6 +87,8 @@ public void findCheckTest() throws Exception {
     Check lookupCheck = onfido.findCheck(check.getId());
 
     Assertions.assertEquals(check.getApplicantId(), lookupCheck.getApplicantId());
+
+    Assertions.assertNotNull(check.toJson());
   }
 
   @Test
@@ -96,6 +100,8 @@ public void listChecks() throws Exception {
 
     Assertions.assertEquals(applicant.getId(), checks.get(0).getApplicantId());
     Assertions.assertEquals(1, checks.size());
+
+    Assertions.assertNotNull(checks.get(0).toJson());
   }
 
   @Test
diff --git a/src/test/java/com/onfido/integration/DocumentTest.java b/src/test/java/com/onfido/integration/DocumentTest.java
index bda45db..885e35a 100644
--- a/src/test/java/com/onfido/integration/DocumentTest.java
+++ b/src/test/java/com/onfido/integration/DocumentTest.java
@@ -25,6 +25,8 @@ public void setupTest() throws Exception {
   @Test
   public void uploadDocumentTest() throws Exception {
     Assertions.assertEquals("sample_driving_licence.png", document.getFileName());
+
+    Assertions.assertNotNull(document.toJson());
   }
 
   @Test
@@ -51,6 +53,7 @@ public void findDocumentTest() throws Exception {
     Document lookupDocument = onfido.findDocument(document.getId());
 
     Assertions.assertEquals("sample_driving_licence.png", lookupDocument.getFileName());
+    Assertions.assertNotNull(lookupDocument.toJson());
   }
 
   @Test
@@ -66,6 +69,9 @@ public void listDocumentsTest() throws Exception {
     Assertions.assertEquals(FileTypeEnum.JPEG, documents.get(0).getFileType());
     Assertions.assertEquals("sample_driving_licence.png", documents.get(1).getFileName());
     Assertions.assertEquals(FileTypeEnum.PNG, documents.get(1).getFileType());
+
+    Assertions.assertNotNull(documents.get(0).toJson());
+    Assertions.assertNotNull(documents.get(1).toJson());
   }
 
   @Test
diff --git a/src/test/java/com/onfido/integration/ExtractionTest.java b/src/test/java/com/onfido/integration/ExtractionTest.java
index be4128c..ae2ad4b 100644
--- a/src/test/java/com/onfido/integration/ExtractionTest.java
+++ b/src/test/java/com/onfido/integration/ExtractionTest.java
@@ -50,5 +50,9 @@ public void performExtractionTest() throws Exception {
     Assertions.assertEquals("SARAH", extractedData.getFirstName());
     Assertions.assertEquals("MORGAN", extractedData.getLastName());
     Assertions.assertEquals(GenderEnum.FEMALE, extractedData.getGender());
+
+    Assertions.assertNotNull(extraction.toJson());
+    Assertions.assertNotNull(documentClassification.toJson());
+    Assertions.assertNotNull(extractedData.toJson());
   }
 }
diff --git a/src/test/java/com/onfido/integration/IdPhotoTest.java b/src/test/java/com/onfido/integration/IdPhotoTest.java
index 4bfafe1..d7dba1c 100644
--- a/src/test/java/com/onfido/integration/IdPhotoTest.java
+++ b/src/test/java/com/onfido/integration/IdPhotoTest.java
@@ -25,6 +25,8 @@ public void setupTest() throws Exception {
   @Test
   public void uploadIdPhotoTest() throws Exception {
     Assertions.assertEquals(idPhoto.getId() + ".png", idPhoto.getFileName());
+
+    Assertions.assertNotNull(idPhoto.toJson());
   }
 
   @Test
@@ -51,6 +53,8 @@ public void findIdPhotoTest() throws Exception {
     IdPhoto lookupIdPhoto = onfido.findIdPhoto(idPhoto.getId());
 
     Assertions.assertEquals(idPhoto.getId() + ".png", lookupIdPhoto.getFileName());
+
+    Assertions.assertNotNull(idPhoto.toJson());
   }
 
   @Test
@@ -64,5 +68,8 @@ public void listIdPhotosTest() throws Exception {
 
     Assertions.assertEquals(idPhotos.get(0).getId() + ".png", idPhotos.get(0).getFileName());
     Assertions.assertEquals(idPhotos.get(1).getId() + ".png", idPhotos.get(1).getFileName());
+
+    Assertions.assertNotNull(idPhotos.get(0).toJson());
+    Assertions.assertNotNull(idPhotos.get(1).toJson());
   }
 }
diff --git a/src/test/java/com/onfido/integration/LivePhotoTest.java b/src/test/java/com/onfido/integration/LivePhotoTest.java
index 39dfb85..1d22744 100644
--- a/src/test/java/com/onfido/integration/LivePhotoTest.java
+++ b/src/test/java/com/onfido/integration/LivePhotoTest.java
@@ -25,6 +25,8 @@ public void setupTest() throws Exception {
   @Test
   public void uploadLivePhotoTest() throws Exception {
     Assertions.assertEquals("sample_photo.png", livePhoto.getFileName());
+
+    Assertions.assertNotNull(livePhoto.toJson());
   }
 
   @Test
@@ -51,6 +53,8 @@ public void findLivePhotoTest() throws Exception {
     LivePhoto lookupLivePhoto = onfido.findLivePhoto(livePhoto.getId());
 
     Assertions.assertEquals("sample_photo.png", lookupLivePhoto.getFileName());
+
+    Assertions.assertNotNull(lookupLivePhoto.toJson());
   }
 
   @Test
@@ -64,5 +68,8 @@ public void listLivePhotosTest() throws Exception {
 
     Assertions.assertEquals("another_sample_photo.png", livePhotos.get(0).getFileName());
     Assertions.assertEquals("sample_photo.png", livePhotos.get(1).getFileName());
+
+    Assertions.assertNotNull(livePhotos.get(0).toJson());
+    Assertions.assertNotNull(livePhotos.get(1).toJson());
   }
 }
diff --git a/src/test/java/com/onfido/integration/LiveVideoTest.java b/src/test/java/com/onfido/integration/LiveVideoTest.java
index 11be97f..5c1bd43 100644
--- a/src/test/java/com/onfido/integration/LiveVideoTest.java
+++ b/src/test/java/com/onfido/integration/LiveVideoTest.java
@@ -52,6 +52,8 @@ public void findLiveVideoTest() throws Exception {
     LiveVideo liveVideo = onfido.findLiveVideo(sampleLiveVideoId1);
 
     Assertions.assertEquals("video.mov", liveVideo.getFileName());
+
+    Assertions.assertNotNull(liveVideo.toJson());
   }
 
   @Test
@@ -60,5 +62,8 @@ public void listLiveVideosTest() throws Exception {
 
     Assertions.assertEquals("video.mov", liveVideos.get(0).getFileName());
     Assertions.assertEquals("video.mov", liveVideos.get(1).getFileName());
+
+    Assertions.assertNotNull(liveVideos.get(0).toJson());
+    Assertions.assertNotNull(liveVideos.get(1).toJson());
   }
 }
diff --git a/src/test/java/com/onfido/integration/MotionCaptureTest.java b/src/test/java/com/onfido/integration/MotionCaptureTest.java
index 14557c1..922fd30 100644
--- a/src/test/java/com/onfido/integration/MotionCaptureTest.java
+++ b/src/test/java/com/onfido/integration/MotionCaptureTest.java
@@ -57,6 +57,8 @@ public void findMotionCaptureTest() throws Exception {
     MotionCapture motionCapture = onfido.findMotionCapture(EXAMPLE_ID_1);
 
     Assertions.assertEquals(expectedFilename, motionCapture.getFileName());
+
+    Assertions.assertNotNull(motionCapture.toJson());
   }
 
   @Test
@@ -65,5 +67,8 @@ public void listMotionCapturesTest() throws Exception {
         onfido.listMotionCaptures(sampleApplicantId).getMotionCaptures();
 
     Assertions.assertEquals(2, motionCaptures.size());
+
+    Assertions.assertNotNull(motionCaptures.get(0).toJson());
+    Assertions.assertNotNull(motionCaptures.get(1).toJson());
   }
 }
diff --git a/src/test/java/com/onfido/integration/ReportSchemasTest.java b/src/test/java/com/onfido/integration/ReportSchemasTest.java
index 68fadc2..36935d1 100644
--- a/src/test/java/com/onfido/integration/ReportSchemasTest.java
+++ b/src/test/java/com/onfido/integration/ReportSchemasTest.java
@@ -56,6 +56,10 @@ public void schemaOfDocumentReportIsValid() throws Exception {
     Assertions.assertNotNull(documentReport.getDocumentReport().getBreakdown());
     Assertions.assertNotNull(documentReport.getDocumentReport().getProperties());
     Assertions.assertNull(documentReport.getDocumentReport().getProperties().getDocumentSubtype());
+
+    Assertions.assertNotNull(documentReport.getDocumentReport().toJson());
+    Assertions.assertNotNull(documentReport.getDocumentReport().getBreakdown().toJson());
+    Assertions.assertNotNull(documentReport.getDocumentReport().getProperties().toJson());
   }
 
   @Test
@@ -89,5 +93,13 @@ public void schemaOfFacialSimilarityPhotoReportIsValid() throws Exception {
         facialSimilarityPhotoFullyAutoReport
             .getFacialSimilarityPhotoFullyAutoReport()
             .getProperties());
+
+    Assertions.assertNotNull(
+        facialSimilarityPhotoFullyAutoReport.getFacialSimilarityPhotoFullyAutoReport().toJson());
+    Assertions.assertNotNull(
+        facialSimilarityPhotoFullyAutoReport
+            .getFacialSimilarityPhotoFullyAutoReport()
+            .getProperties()
+            .toJson());
   }
 }
diff --git a/src/test/java/com/onfido/integration/SdkTokenTest.java b/src/test/java/com/onfido/integration/SdkTokenTest.java
index 8dfd361..86090ce 100644
--- a/src/test/java/com/onfido/integration/SdkTokenTest.java
+++ b/src/test/java/com/onfido/integration/SdkTokenTest.java
@@ -19,5 +19,7 @@ public void generateTokenTest() throws Exception {
                 .referrer("https://*.example.com/example_page/*"));
 
     Assertions.assertTrue(token.getToken().length() > 0);
+
+    Assertions.assertNotNull(token.toJson());
   }
 }
diff --git a/src/test/java/com/onfido/integration/TasksTest.java b/src/test/java/com/onfido/integration/TasksTest.java
index 358f844..a554a63 100644
--- a/src/test/java/com/onfido/integration/TasksTest.java
+++ b/src/test/java/com/onfido/integration/TasksTest.java
@@ -29,6 +29,9 @@ public void listTasks() throws Exception {
     List<TaskItem> tasks = onfido.listTasks(workflowRunId);
 
     Assertions.assertEquals(2, tasks.size());
+
+    Assertions.assertNotNull(tasks.get(0).toJson());
+    Assertions.assertNotNull(tasks.get(1).toJson());
   }
 
   @Test
@@ -39,6 +42,8 @@ public void findTask() throws Exception {
 
     Assertions.assertEquals(lookupTask.getId(), task.getId());
     Assertions.assertEquals(lookupTask.getTaskDefId(), task.getTaskDefId());
+
+    Assertions.assertNotNull(task.toJson());
   }
 
   @Test
diff --git a/src/test/java/com/onfido/integration/WebhookTest.java b/src/test/java/com/onfido/integration/WebhookTest.java
index 9cd1e82..a17f460 100644
--- a/src/test/java/com/onfido/integration/WebhookTest.java
+++ b/src/test/java/com/onfido/integration/WebhookTest.java
@@ -36,6 +36,8 @@ private Webhook createWebhook(String url) throws Exception {
   @Test
   public void createWebhookTest() throws Exception {
     Assertions.assertEquals("https://example.com/webhook", webhook.getUrl());
+
+    Assertions.assertNotNull(webhook.toJson());
   }
 
   @Test
@@ -43,6 +45,8 @@ public void findWebhookTest() throws Exception {
     Webhook lookupWebhook = onfido.findWebhook(webhook.getId());
 
     Assertions.assertEquals("https://example.com/webhook", lookupWebhook.getUrl());
+
+    Assertions.assertNotNull(lookupWebhook.toJson());
   }
 
   @Test
@@ -52,6 +56,8 @@ public void updateWebhookTest() throws Exception {
             webhook.getId(), new WebhookUpdater().url("https://example.com/webhook/updated"));
 
     Assertions.assertEquals("https://example.com/webhook/updated", updatedWebhook.getUrl());
+
+    Assertions.assertNotNull(updatedWebhook.toJson());
   }
 
   @Test
@@ -72,6 +78,9 @@ public void listWebhooksTest() throws Exception {
     Assertions.assertEquals(3, webhooks.size());
     Assertions.assertEquals("https://example.com/firstWebhook", webhooks.get(0).getUrl());
     Assertions.assertEquals("https://example.com/secondWebhook", webhooks.get(1).getUrl());
+
+    Assertions.assertNotNull(webhooks.get(0).toJson());
+    Assertions.assertNotNull(webhooks.get(1).toJson());
   }
 
   @Test
diff --git a/src/test/java/com/onfido/integration/WorkflowRunTest.java b/src/test/java/com/onfido/integration/WorkflowRunTest.java
index 93e510c..49f9637 100644
--- a/src/test/java/com/onfido/integration/WorkflowRunTest.java
+++ b/src/test/java/com/onfido/integration/WorkflowRunTest.java
@@ -30,6 +30,8 @@ public void setup() throws Exception {
   public void createWorkflowRunTest() throws Exception {
     Assertions.assertEquals(WORKFLOW_ID, workflowRun.getWorkflowId());
     Assertions.assertEquals(applicantId, workflowRun.getApplicantId());
+
+    Assertions.assertNotNull(workflowRun.toJson());
   }
 
   @Test
@@ -50,6 +52,8 @@ public void createWorkflowRunWithCustomInputsTest() throws Exception {
     Assertions.assertEquals(applicantId, workflowRunWithCustomInputs.getApplicantId());
     Assertions.assertEquals(
         WorkflowRun.StatusEnum.APPROVED, workflowRunWithCustomInputs.getStatus());
+
+    Assertions.assertNotNull(workflowRunWithCustomInputs.toJson());
   }
 
   @Test
@@ -58,6 +62,8 @@ public void findWorkflowRunTest() throws Exception {
 
     Assertions.assertEquals(WORKFLOW_ID, lookupWorkflowRun.getWorkflowId());
     Assertions.assertEquals(applicantId, lookupWorkflowRun.getApplicantId());
+
+    Assertions.assertNotNull(lookupWorkflowRun.toJson());
   }
 
   @Test
@@ -78,6 +84,8 @@ public void generateTimelineFileTest() throws Exception {
 
     Assertions.assertNotNull(workflowTimelineFileData.getWorkflowTimelineFileId());
     Assertions.assertNotNull(workflowTimelineFileData.getHref());
+
+    Assertions.assertNotNull(workflowTimelineFileData.toJson());
   }
 
   @Test