diff --git a/build.gradle b/build.gradle
index a46e1265ae6..8d9eb03c118 100644
--- a/build.gradle
+++ b/build.gradle
@@ -515,6 +515,8 @@ dependencies {
 
   testImplementation group: 'org.jeasy', name: 'easy-random-core', version: '5.0.0'
 
+  testImplementation 'com.atlassian.oai:swagger-request-validator-core:2.46.0'
+
   compileJava.dependsOn = openApiGenerateTaskList
 }
 
diff --git a/src/integrationTest/java/uk/gov/hmcts/darts/authorisation/component/impl/AuthorisationImplTest.java b/src/integrationTest/java/uk/gov/hmcts/darts/authorisation/component/impl/AuthorisationImplTest.java
index afa2035c001..95014f790ec 100644
--- a/src/integrationTest/java/uk/gov/hmcts/darts/authorisation/component/impl/AuthorisationImplTest.java
+++ b/src/integrationTest/java/uk/gov/hmcts/darts/authorisation/component/impl/AuthorisationImplTest.java
@@ -29,7 +29,7 @@
 import static uk.gov.hmcts.darts.common.enums.SecurityRoleEnum.JUDICIARY;
 import static uk.gov.hmcts.darts.common.enums.SecurityRoleEnum.REQUESTER;
 import static uk.gov.hmcts.darts.hearings.exception.HearingApiError.HEARING_NOT_FOUND;
-import static uk.gov.hmcts.darts.transcriptions.exception.TranscriptionApiError.TRANSCRIPTION_NOT_FOUND;
+import static uk.gov.hmcts.darts.transcriptions.exception.TranscriptionApiError.BAD_REQUEST_TRANSCRIPTION_ID;
 
 class AuthorisationImplTest extends IntegrationBase {
 
@@ -222,8 +222,8 @@ void authoriseByTranscriptionIdShouldThrowTranscriptionApiErrorTranscriptionNotF
                 -1L, Set.of(JUDICIARY))
         );
 
-        assertEquals(TRANSCRIPTION_NOT_FOUND.getTitle(), exception.getMessage());
-        assertEquals(TRANSCRIPTION_NOT_FOUND, exception.getError());
+        assertEquals(BAD_REQUEST_TRANSCRIPTION_ID.getTitle(), exception.getMessage());
+        assertEquals(BAD_REQUEST_TRANSCRIPTION_ID, exception.getError());
     }
 
     @Test
diff --git a/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerDownloadTranscriptIntTest.java b/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerDownloadTranscriptIntTest.java
index 37894f955a8..db3bffff7d8 100644
--- a/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerDownloadTranscriptIntTest.java
+++ b/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerDownloadTranscriptIntTest.java
@@ -54,6 +54,7 @@
 import static uk.gov.hmcts.darts.audit.api.AuditActivity.DOWNLOAD_TRANSCRIPTION;
 import static uk.gov.hmcts.darts.common.enums.ExternalLocationTypeEnum.UNSTRUCTURED;
 import static uk.gov.hmcts.darts.common.enums.ObjectRecordStatusEnum.STORED;
+import static uk.gov.hmcts.darts.test.common.TestUtils.getContentsFromFile;
 import static uk.gov.hmcts.darts.transcriptions.enums.TranscriptionStatusEnum.APPROVED;
 import static uk.gov.hmcts.darts.transcriptions.enums.TranscriptionStatusEnum.COMPLETE;
 import static uk.gov.hmcts.darts.transcriptions.enums.TranscriptionStatusEnum.WITH_TRANSCRIBER;
@@ -163,7 +164,7 @@ void downloadTranscript_shouldReturn401Error_whenUserNotFound() throws Exception
     }
 
     @Test
-    void downloadTranscriptShouldReturnNotFoundError() throws Exception {
+    void downloadTranscript_ShouldReturnNotFoundError() throws Exception {
         MockHttpServletRequestBuilder requestBuilder = MockMvcRequestBuilders.get(URL_TEMPLATE, transcriptionId)
             .header(
                 "accept",
@@ -185,7 +186,7 @@ void downloadTranscriptShouldReturnNotFoundError() throws Exception {
     }
 
     @Test
-    void downloadTranscriptShouldReturnOkWithMicrosoftWordNew() throws Exception {
+    void downloadTranscript_ShouldReturnOk_WithMicrosoftWordNew() throws Exception {
         final String fileName = "Test Document.docx";
         final String fileType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document";
         final int fileSize = 11_937;
@@ -257,7 +258,7 @@ void downloadTranscriptShouldReturnOkWithMicrosoftWordNew() throws Exception {
 
     @Test
     @SuppressWarnings("PMD.CloseResource")
-    void downloadTranscriptShouldReturnOkWithMicrosoftWordOld() throws Exception {
+    void downloadTranscript_ShouldReturnOk_WithMicrosoftWordOld() throws Exception {
         final String fileName = "Test Document.doc";
         final String fileType = "application/msword";
         final int fileSize = 22_528;
@@ -319,4 +320,23 @@ void downloadTranscriptShouldReturnOkWithMicrosoftWordOld() throws Exception {
         verifyNoMoreInteractions(mockAuditApi, mockDataManagementFacade, mockFileBasedDownloadResponseMetaData);
     }
 
+    @Test
+    void downloadTranscript_ShouldReturnBadRequest_WhenNegativeTranscriptionIdUsed() throws Exception {
+        MockHttpServletRequestBuilder requestBuilder = MockMvcRequestBuilders.get("/transcriptions/-123/document")
+            .header(
+                "accept",
+                "application/msword",
+                "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
+            );
+        MvcResult mvcResult = mockMvc.perform(requestBuilder)
+            .andExpect(status().isBadRequest())
+            .andReturn();
+
+        String actualResponse = mvcResult.getResponse().getContentAsString();
+
+        String expectedResponse = getContentsFromFile("tests/transcriptions/transcription/expectedResponseBadRequest.json");
+        JSONAssert.assertEquals(expectedResponse, actualResponse, JSONCompareMode.NON_EXTENSIBLE);
+
+        verifyNoInteractions(mockAuditApi);
+    }
 }
\ No newline at end of file
diff --git a/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerGetTranscriptionTest.java b/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerGetTranscriptionTest.java
index ca64989e2e9..4dd1849813d 100644
--- a/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerGetTranscriptionTest.java
+++ b/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerGetTranscriptionTest.java
@@ -287,8 +287,33 @@ void getTranscriptionNotFoundWhenIsCurrentFalse() throws Exception {
     }
 
     @Test
-    void getTranscriptionNotFound() throws Exception {
+    void getTranscription_ShouldReturnBadRequest_WhenNegativeTranscriptionId() throws Exception {
         MockHttpServletRequestBuilder requestBuilder = get(ENDPOINT_URL_TRANSCRIPTION, -999);
+        MvcResult response = mockMvc.perform(requestBuilder).andExpect(status().isBadRequest()).andReturn();
+        String actualResponse = response.getResponse().getContentAsString();
+        String expectedResponse = getContentsFromFile("tests/transcriptions/transcription/expectedResponseBadRequest.json");
+        JSONAssert.assertEquals(expectedResponse, actualResponse, JSONCompareMode.NON_EXTENSIBLE);
+    }
+
+    @Test
+    void getTranscription_ShouldReturnNotFound_WhenTranscriptDoesNotExist() throws Exception {
+        TranscriptionEntity transcriptionEntity = transactionalUtil.executeInTransaction(() -> {
+            HearingEntity hearingEntity = dartsDatabase.getHearingRepository().findAll().getFirst();
+            TranscriptionEntity transcription = dartsDatabase.getTranscriptionStub().createTranscription(hearingEntity);
+            transcription.setStartTime(SOME_DATE_TIME);
+            transcription.setEndTime(SOME_DATE_TIME);
+            transcription = dartsDatabase.save(transcription);
+            UserAccountEntity userAccount = dartsDatabase.getUserAccountRepository().findById(transcription.getCreatedById()).orElseThrow();
+
+            addTranscriptionWorkflow(transcription, userAccount, "comment1", TranscriptionStatusEnum.REQUESTED);
+            addTranscriptionWorkflow(transcription, userAccount, "comment2", TranscriptionStatusEnum.APPROVED);
+            transcription.getCourtroom().getCourthouse().getCourthouseName();
+            transcription.getRequestedBy().getUserName();
+            return transcription;
+        });
+        dartsDatabase.updateCreatedBy(transcriptionEntity, OffsetDateTime.of(2023, 6, 20, 10, 0, 0, 0, ZoneOffset.UTC));
+
+        MockHttpServletRequestBuilder requestBuilder = get(ENDPOINT_URL_TRANSCRIPTION, transcriptionEntity.getId() + 1);
         MvcResult response = mockMvc.perform(requestBuilder).andExpect(status().isNotFound()).andReturn();
         String actualResponse = response.getResponse().getContentAsString();
         String expectedResponse = getContentsFromFile("tests/transcriptions/transcription/expectedResponseNotFound.json");
diff --git a/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerUpdateTranscriptionUnfulfilledIntTest.java b/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerUpdateTranscriptionUnfulfilledIntTest.java
index 850be5273ac..ff662ec8146 100644
--- a/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerUpdateTranscriptionUnfulfilledIntTest.java
+++ b/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerUpdateTranscriptionUnfulfilledIntTest.java
@@ -40,6 +40,7 @@
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.patch;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 import static uk.gov.hmcts.darts.audit.api.AuditActivity.UNFULFILLED_TRANSCRIPTION;
+import static uk.gov.hmcts.darts.test.common.TestUtils.getContentsFromFile;
 import static uk.gov.hmcts.darts.transcriptions.enums.TranscriptionStatusEnum.CLOSED;
 import static uk.gov.hmcts.darts.transcriptions.enums.TranscriptionStatusEnum.UNFULFILLED;
 import static uk.gov.hmcts.darts.transcriptions.enums.TranscriptionStatusEnum.WITH_TRANSCRIBER;
@@ -168,12 +169,11 @@ void updateTranscription_ShouldReturnTranscriptionUnprocessableEntityError_Where
     }
 
     @Test
-    void updateTranscription_ShouldReturnTranscriptionNotFoundError() throws Exception {
+    void updateTranscription_ShouldReturnTranscriptionNotFoundError_WhenTranscriptionDoesNotExist() throws Exception {
         UpdateTranscriptionRequest updateTranscription = new UpdateTranscriptionRequest();
         updateTranscription.setTranscriptionStatusId(UNFULFILLED.getId());
-
         MockHttpServletRequestBuilder requestBuilder = patch(URI.create(
-            String.format("/transcriptions/%d", -1)))
+            String.format("/transcriptions/%d", transcriptionId + 1)))
             .header("Content-Type", "application/json")
             .content(objectMapper.writeValueAsString(updateTranscription));
         MvcResult mvcResult = mockMvc.perform(requestBuilder)
@@ -189,6 +189,27 @@ void updateTranscription_ShouldReturnTranscriptionNotFoundError() throws Excepti
         verifyNoInteractions(mockAuditApi);
     }
 
+    @Test
+    void updateTranscription_ShouldReturnTranscriptionBadRequestError_WhenNegativeTranscriptionIdUsed() throws Exception {
+        UpdateTranscriptionRequest updateTranscription = new UpdateTranscriptionRequest();
+        updateTranscription.setTranscriptionStatusId(UNFULFILLED.getId());
+
+        MockHttpServletRequestBuilder requestBuilder = patch(URI.create(
+            String.format("/transcriptions/%d", -1)))
+            .header("Content-Type", "application/json")
+            .content(objectMapper.writeValueAsString(updateTranscription));
+        MvcResult mvcResult = mockMvc.perform(requestBuilder)
+            .andExpect(status().isBadRequest())
+            .andReturn();
+
+        String actualJson = mvcResult.getResponse().getContentAsString();
+        String expectedJson = getContentsFromFile("tests/transcriptions/transcription/expectedResponseBadRequest.json");
+
+        JSONAssert.assertEquals(expectedJson, actualJson, JSONCompareMode.NON_EXTENSIBLE);
+        verifyNoInteractions(notificationApi);
+        verifyNoInteractions(mockAuditApi);
+    }
+
     @Test
     void updateTranscription_ShouldReturnTranscriptionWorkflowActionInvalidError() throws Exception {
         UpdateTranscriptionRequest updateTranscription = new UpdateTranscriptionRequest();
diff --git a/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerUpdateTranscriptionWithTranscriberIntTest.java b/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerUpdateTranscriptionWithTranscriberIntTest.java
index 7e48f1e6a72..eb05aeb2558 100644
--- a/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerUpdateTranscriptionWithTranscriberIntTest.java
+++ b/src/integrationTest/java/uk/gov/hmcts/darts/transcriptions/controller/TranscriptionControllerUpdateTranscriptionWithTranscriberIntTest.java
@@ -36,6 +36,7 @@
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.patch;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 import static uk.gov.hmcts.darts.audit.api.AuditActivity.ACCEPT_TRANSCRIPTION;
+import static uk.gov.hmcts.darts.test.common.TestUtils.getContentsFromFile;
 import static uk.gov.hmcts.darts.transcriptions.enums.TranscriptionStatusEnum.APPROVED;
 import static uk.gov.hmcts.darts.transcriptions.enums.TranscriptionStatusEnum.COMPLETE;
 import static uk.gov.hmcts.darts.transcriptions.enums.TranscriptionStatusEnum.WITH_TRANSCRIBER;
@@ -133,7 +134,7 @@ void updateTranscriptionWithTranscriberWithoutComment() throws Exception {
     }
 
     @Test
-    void updateTranscriptionShouldReturnTranscriptionNotFoundError() throws Exception {
+    void updateTranscription_ShouldReturnBadRequest_WhenInvalidTranscriptionId() throws Exception {
         UpdateTranscriptionRequest updateTranscription = new UpdateTranscriptionRequest();
         updateTranscription.setTranscriptionStatusId(WITH_TRANSCRIBER.getId());
 
@@ -141,14 +142,33 @@ void updateTranscriptionShouldReturnTranscriptionNotFoundError() throws Exceptio
             String.format("/transcriptions/%d", -1)))
             .header("Content-Type", "application/json")
             .content(objectMapper.writeValueAsString(updateTranscription));
+        MvcResult mvcResult = mockMvc.perform(requestBuilder)
+            .andExpect(status().isBadRequest())
+            .andReturn();
+
+        String actualJson = mvcResult.getResponse().getContentAsString();
+        String expectedJson = getContentsFromFile("tests/transcriptions/transcription/expectedResponseBadRequest.json");
+        JSONAssert.assertEquals(expectedJson, actualJson, JSONCompareMode.NON_EXTENSIBLE);
+
+        verifyNoInteractions(mockAuditApi);
+    }
+
+    @Test
+    void updateTranscription_ShouldReturnNotFound_WhenTranscriptionDoesNotExist() throws Exception {
+        UpdateTranscriptionRequest updateTranscription = new UpdateTranscriptionRequest();
+        updateTranscription.setTranscriptionStatusId(WITH_TRANSCRIBER.getId());
+
+        MockHttpServletRequestBuilder requestBuilder = patch(URI.create(
+            String.format("/transcriptions/%d", transcriptionId + 1)))
+            .header("Content-Type", "application/json")
+            .content(objectMapper.writeValueAsString(updateTranscription));
         MvcResult mvcResult = mockMvc.perform(requestBuilder)
             .andExpect(status().isNotFound())
             .andReturn();
 
         String actualJson = mvcResult.getResponse().getContentAsString();
-        String expectedJson = """
-            {"type":"TRANSCRIPTION_101","title":"The requested transcription cannot be found","status":404}
-            """;
+        String expectedJson = getContentsFromFile("tests/transcriptions/transcription/expectedResponseNotFound.json");
+
         JSONAssert.assertEquals(expectedJson, actualJson, JSONCompareMode.NON_EXTENSIBLE);
 
         verifyNoInteractions(mockAuditApi);
diff --git a/src/integrationTest/resources/tests/transcriptions/transcription/expectedResponseBadRequest.json b/src/integrationTest/resources/tests/transcriptions/transcription/expectedResponseBadRequest.json
new file mode 100644
index 00000000000..643e0cd7fdf
--- /dev/null
+++ b/src/integrationTest/resources/tests/transcriptions/transcription/expectedResponseBadRequest.json
@@ -0,0 +1 @@
+{"type":"TRANSCRIPTION_124","title":"Invalid transcription id","status":400}
\ No newline at end of file
diff --git a/src/main/java/uk/gov/hmcts/darts/authorisation/component/impl/AuthorisationImpl.java b/src/main/java/uk/gov/hmcts/darts/authorisation/component/impl/AuthorisationImpl.java
index 8dc6e254d5d..3c1f89772fc 100644
--- a/src/main/java/uk/gov/hmcts/darts/authorisation/component/impl/AuthorisationImpl.java
+++ b/src/main/java/uk/gov/hmcts/darts/authorisation/component/impl/AuthorisationImpl.java
@@ -4,6 +4,7 @@
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.collections4.CollectionUtils;
+import org.apache.coyote.BadRequestException;
 import org.springframework.stereotype.Component;
 import uk.gov.hmcts.darts.audio.entity.MediaRequestEntity;
 import uk.gov.hmcts.darts.authorisation.api.AuthorisationApi;
@@ -22,6 +23,8 @@
 import uk.gov.hmcts.darts.common.repository.MediaRequestRepository;
 import uk.gov.hmcts.darts.common.repository.TranscriptionRepository;
 import uk.gov.hmcts.darts.common.repository.TransformedMediaRepository;
+import uk.gov.hmcts.darts.util.DataUtil;
+import uk.gov.hmcts.darts.util.ValidationConstants;
 
 import java.util.Collections;
 import java.util.List;
@@ -36,6 +39,7 @@
 import static uk.gov.hmcts.darts.audio.exception.AudioRequestsApiError.TRANSFORMED_MEDIA_NOT_FOUND;
 import static uk.gov.hmcts.darts.cases.exception.CaseApiError.CASE_NOT_FOUND;
 import static uk.gov.hmcts.darts.hearings.exception.HearingApiError.HEARING_NOT_FOUND;
+import static uk.gov.hmcts.darts.transcriptions.exception.TranscriptionApiError.BAD_REQUEST_TRANSCRIPTION_ID;
 import static uk.gov.hmcts.darts.transcriptions.exception.TranscriptionApiError.TRANSCRIPTION_NOT_FOUND;
 
 @Component
@@ -115,6 +119,9 @@ public void authoriseByMediaId(Long mediaId, Set<SecurityRoleEnum> securityRoles
     @SuppressWarnings({"PMD.ExceptionAsFlowControl"})
     public void authoriseByTranscriptionId(Long transcriptionId, Set<SecurityRoleEnum> securityRoles) {
         try {
+            if (!DataUtil.isWithinBounds(transcriptionId, 1L, ValidationConstants.MaxValues.MAX_LONG_VALUE)) {
+                throw new BadRequestException();
+            }
             final List<CourthouseEntity> courthouses = getCourthousesFromTranscription(transcriptionId);
             if (CollectionUtils.isEmpty(courthouses)) {
                 throw new EntityNotFoundException();
@@ -123,6 +130,9 @@ public void authoriseByTranscriptionId(Long transcriptionId, Set<SecurityRoleEnu
         } catch (EntityNotFoundException ex) {
             log.error("Unable to find Transcription-Courtroom-Courthouse for checkAuthorisation. TranscriptionId={}", transcriptionId, ex);
             throw new DartsApiException(TRANSCRIPTION_NOT_FOUND, ex);
+        } catch (BadRequestException ex) {
+            log.error("TranscriptionId is out of accepted range. TranscriptionId={}", transcriptionId, ex);
+            throw new DartsApiException(BAD_REQUEST_TRANSCRIPTION_ID, ex);
         }
     }
 
diff --git a/src/main/java/uk/gov/hmcts/darts/transcriptions/exception/TranscriptionApiError.java b/src/main/java/uk/gov/hmcts/darts/transcriptions/exception/TranscriptionApiError.java
index 5645d766dc3..55e5aa1b587 100644
--- a/src/main/java/uk/gov/hmcts/darts/transcriptions/exception/TranscriptionApiError.java
+++ b/src/main/java/uk/gov/hmcts/darts/transcriptions/exception/TranscriptionApiError.java
@@ -133,7 +133,12 @@ public enum TranscriptionApiError implements DartsApiError {
     TOO_MANY_RESULTS(
         TranscriptionsErrorCode.TOO_MANY_RESULTS.getValue(),
         HttpStatus.UNPROCESSABLE_ENTITY,
-        TranscriptionsTitleErrors.TOO_MANY_RESULTS.getValue());
+        TranscriptionsTitleErrors.TOO_MANY_RESULTS.getValue()
+    ),
+    BAD_REQUEST_TRANSCRIPTION_ID(
+        TranscriptionsErrorCode.BAD_REQUEST_TRANSCRIPTION_ID.getValue(),
+        HttpStatus.BAD_REQUEST,
+        TranscriptionsTitleErrors.BAD_REQUEST_TRANSCRIPTION_ID.getValue());
 
 
     private static final String ERROR_TYPE_PREFIX = "TRANSCRIPTION";
diff --git a/src/main/java/uk/gov/hmcts/darts/util/DataUtil.java b/src/main/java/uk/gov/hmcts/darts/util/DataUtil.java
index 81ec802a583..00a757dcd6b 100644
--- a/src/main/java/uk/gov/hmcts/darts/util/DataUtil.java
+++ b/src/main/java/uk/gov/hmcts/darts/util/DataUtil.java
@@ -125,4 +125,15 @@ public static boolean toBoolean(Boolean value) {
     public static boolean toBoolean(Boolean value, boolean defaultValue) {
         return Optional.ofNullable(value).orElse(defaultValue);
     }
+
+    public static boolean isWithinBounds(Long value, Long min, Long max) {
+        if (value == null) {
+            return false;
+        }
+        if (min != null && value < min) {
+            return false;
+        }
+        return max == null || value <= max;
+    }
+
 }
diff --git a/src/main/java/uk/gov/hmcts/darts/util/ValidationConstants.java b/src/main/java/uk/gov/hmcts/darts/util/ValidationConstants.java
new file mode 100644
index 00000000000..5fe6f6ceccf
--- /dev/null
+++ b/src/main/java/uk/gov/hmcts/darts/util/ValidationConstants.java
@@ -0,0 +1,12 @@
+package uk.gov.hmcts.darts.util;
+
+import lombok.experimental.UtilityClass;
+
+@UtilityClass
+@SuppressWarnings({"HideUtilityClassConstructor", "java:S1118", "PMD.MissingStaticMethodInNonInstantiatableClass"})
+public class ValidationConstants {
+
+    public static class  MaxValues {
+        public static final Long MAX_LONG_VALUE = 9_223_372_036_854_775_807L;
+    }
+}
diff --git a/src/main/resources/openapi/annotations.yaml b/src/main/resources/openapi/annotations.yaml
index c5ea6c38c6f..8a738dab141 100644
--- a/src/main/resources/openapi/annotations.yaml
+++ b/src/main/resources/openapi/annotations.yaml
@@ -32,7 +32,7 @@ paths:
                 annotation:
                   $ref: '#/components/schemas/annotation'
       responses:
-        201:
+        '201':
           description: CREATED
           content:
             application/json:
@@ -43,7 +43,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: Bad Request Error
           content:
@@ -78,7 +78,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: Bad Request Error
           content:
@@ -132,7 +132,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: Bad Request Error
           content:
diff --git a/src/main/resources/openapi/audio.yaml b/src/main/resources/openapi/audio.yaml
index b796e3cfdd0..cba8c1ee810 100644
--- a/src/main/resources/openapi/audio.yaml
+++ b/src/main/resources/openapi/audio.yaml
@@ -106,7 +106,7 @@ paths:
             type: string
           description: "Range header, required for streaming audio."
       responses:
-        200:
+        '200':
           description: OK
           content:
             audio/mpeg:
@@ -149,7 +149,7 @@ paths:
                 type: "AUDIO_102"
                 title: "The requested media cannot be found"
                 status: 404
-        500:
+        '500':
           description: The requested data cannot be located
           content:
             application/json+problem:
@@ -172,15 +172,15 @@ paths:
             schema:
               $ref: '#/components/schemas/AddAudioMetadataRequestWithStorageGUID'
       responses:
-        200:
+        '200':
           description: Audio metadata accepted
-        400:
+        '400':
           description: Bad request
           content:
             application/json+problem:
               schema:
                 $ref: './problem.yaml'
-        500:
+        '500':
           description: Internal server error
           content:
             application/json+problem:
@@ -201,7 +201,7 @@ paths:
             type: integer
           required: true
       responses:
-        200:
+        '200':
           description: OK
           content:
             application/json:
diff --git a/src/main/resources/openapi/audiorequests.yaml b/src/main/resources/openapi/audiorequests.yaml
index 3d7554fa872..0c0d3208309 100644
--- a/src/main/resources/openapi/audiorequests.yaml
+++ b/src/main/resources/openapi/audiorequests.yaml
@@ -40,7 +40,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: A required parameter is missing or an invalid.
           content:
@@ -81,7 +81,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: A required parameter is missing or an invalid.
           content:
@@ -206,7 +206,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: Bad Request Error
           content:
@@ -327,7 +327,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: 'invalid input, object invalid'
         '401':
@@ -371,7 +371,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: Bad Request Error
           content:
@@ -438,7 +438,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: 'invalid input, object invalid'
         '401':
@@ -499,7 +499,7 @@ paths:
             schema:
               $ref: '#/components/schemas/MediaPatchRequest'
       responses:
-        200:
+        '200':
           description: Media request details
           content:
             application/json:
@@ -529,7 +529,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: Bad request
           content:
@@ -975,27 +975,27 @@ components:
       x-enum-varnames: [ USER_NOT_AUTHORISED_FOR_COURTHOUSE, MEDIA_REQUEST_NOT_VALID_FOR_USER ]
 
     AudioRequestsErrorCode:
-        type: string
-        enum:
-          - "AUDIO_REQUESTS_100"
-          - "AUDIO_REQUESTS_101"
-          - "AUDIO_REQUESTS_102"
-          - "AUDIO_REQUESTS_103"
-          - "AUDIO_REQUESTS_104"
-          - "AUDIO_REQUESTS_105"
-          - "AUDIO_REQUESTS_106"
-          - "AUDIO_REQUESTS_107"
-        x-enum-varnames: [ MEDIA_REQUEST_NOT_FOUND, MEDIA_REQUEST_NOT_VALID_FOR_USER,  MEDIA_REQUEST_TYPE_IS_INVALID_FOR_ENDPOINT, TRANSFORMED_MEDIA_NOT_FOUND, DUPLICATE_MEDIA_REQUEST, USER_NOT_FOUND, INVALID_REQUEST, MAX_HANDHELD_AUDIO_FILES_EXCEEDED ]
+      type: string
+      enum:
+        - "AUDIO_REQUESTS_100"
+        - "AUDIO_REQUESTS_101"
+        - "AUDIO_REQUESTS_102"
+        - "AUDIO_REQUESTS_103"
+        - "AUDIO_REQUESTS_104"
+        - "AUDIO_REQUESTS_105"
+        - "AUDIO_REQUESTS_106"
+        - "AUDIO_REQUESTS_107"
+      x-enum-varnames: [ MEDIA_REQUEST_NOT_FOUND, MEDIA_REQUEST_NOT_VALID_FOR_USER,  MEDIA_REQUEST_TYPE_IS_INVALID_FOR_ENDPOINT, TRANSFORMED_MEDIA_NOT_FOUND, DUPLICATE_MEDIA_REQUEST, USER_NOT_FOUND, INVALID_REQUEST, MAX_HANDHELD_AUDIO_FILES_EXCEEDED ]
 
     AudioRequestsTitleErrors:
-        type: string
-        enum:
-          - "The requested audio request cannot be found"
-          - "The audio request is not valid for this user"
-          - "The audio request is not valid for this action"
-          - "The requested transformed media cannot be found"
-          - "An audio request already exists with these properties"
-          - "Patch media request with user not found"
-          - "Invalid request"
-          - "Max handheld audio files exceed"
-        x-enum-varnames: [ MEDIA_REQUEST_NOT_FOUND, MEDIA_REQUEST_NOT_VALID_FOR_USER,  MEDIA_REQUEST_TYPE_IS_INVALID_FOR_ENDPOINT, TRANSFORMED_MEDIA_NOT_FOUND, DUPLICATE_MEDIA_REQUEST, USER_NOT_FOUND, INVALID_REQUEST, MAX_HANDHELD_AUDIO_FILES_EXCEEDED]
\ No newline at end of file
+      type: string
+      enum:
+        - "The requested audio request cannot be found"
+        - "The audio request is not valid for this user"
+        - "The audio request is not valid for this action"
+        - "The requested transformed media cannot be found"
+        - "An audio request already exists with these properties"
+        - "Patch media request with user not found"
+        - "Invalid request"
+        - "Max handheld audio files exceed"
+      x-enum-varnames: [ MEDIA_REQUEST_NOT_FOUND, MEDIA_REQUEST_NOT_VALID_FOR_USER,  MEDIA_REQUEST_TYPE_IS_INVALID_FOR_ENDPOINT, TRANSFORMED_MEDIA_NOT_FOUND, DUPLICATE_MEDIA_REQUEST, USER_NOT_FOUND, INVALID_REQUEST, MAX_HANDHELD_AUDIO_FILES_EXCEEDED ]
\ No newline at end of file
diff --git a/src/main/resources/openapi/retentions.yaml b/src/main/resources/openapi/retentions.yaml
index e00ade11ae3..6e499bbe542 100644
--- a/src/main/resources/openapi/retentions.yaml
+++ b/src/main/resources/openapi/retentions.yaml
@@ -130,7 +130,7 @@ paths:
       description: "Retention Policy Types"
       parameters: [ ]
       responses:
-        "200":
+        '200':
           description: "OK"
           content:
             application/json:
@@ -251,7 +251,7 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml' 
+                $ref: './problem.yaml'
         '400':
           description: "Bad request"
           content:
@@ -453,7 +453,7 @@ components:
                          NO_RETENTION_POLICIES_APPLIED, INTERNAL_SERVER_ERROR, RETENTION_DATE_TOO_LATE, RETENTION_POLICY_TYPE_ID_NOT_FOUND,
                          NON_UNIQUE_POLICY_NAME, NON_UNIQUE_POLICY_DISPLAY_NAME, DURATION_TOO_SHORT, POLICY_START_MUST_BE_FUTURE,
                          POLICY_START_DATE_MUST_BE_PAST, NON_UNIQUE_FIXED_POLICY_KEY, FIXED_POLICY_KEY_NOT_FOUND, LIVE_POLICIES_CANNOT_BE_EDITED,
-                         TARGET_POLICY_HAS_PENDING_REVISION, CASE_RETENTION_PASSED]
+                         TARGET_POLICY_HAS_PENDING_REVISION, CASE_RETENTION_PASSED ]
 
     RetentionTitleErrors:
       type: string
@@ -481,4 +481,4 @@ components:
                          NO_RETENTION_POLICIES_APPLIED, INTERNAL_SERVER_ERROR, RETENTION_DATE_TOO_LATE, RETENTION_POLICY_TYPE_ID_NOT_FOUND,
                          NON_UNIQUE_POLICY_NAME, NON_UNIQUE_POLICY_DISPLAY_NAME, DURATION_TOO_SHORT, POLICY_START_MUST_BE_FUTURE,
                          POLICY_START_DATE_MUST_BE_PAST, NON_UNIQUE_FIXED_POLICY_KEY, FIXED_POLICY_KEY_NOT_FOUND, LIVE_POLICIES_CANNOT_BE_EDITED,
-                         TARGET_POLICY_HAS_PENDING_REVISION, CASE_RETENTION_PASSED]
+                         TARGET_POLICY_HAS_PENDING_REVISION, CASE_RETENTION_PASSED ]
diff --git a/src/main/resources/openapi/transcriptions.yaml b/src/main/resources/openapi/transcriptions.yaml
index ec449065ee9..cd0e4bd0c28 100644
--- a/src/main/resources/openapi/transcriptions.yaml
+++ b/src/main/resources/openapi/transcriptions.yaml
@@ -358,25 +358,31 @@ paths:
       operationId: downloadTranscript
       parameters:
         - name: transcription_id
+          description: Transcription ID
           in: path
           required: true
           schema:
             type: integer
             format: int64
+            minimum: 1
+            maximum: 9223372036854775807
       responses:
         '200':
           description: OK
           content:
             application/*:
               schema:
+                description: Any non Microsoft Word file type
                 type: string
                 format: binary
             application/msword:
               schema:
+                description: Microsoft Word Document
                 type: string
                 format: binary
             application/vnd.openxmlformats-officedocument.wordprocessingml.document:
               schema:
+                description: Microsoft Word Open XML Document
                 type: string
                 format: binary
         '422':
@@ -390,10 +396,17 @@ paths:
           content:
             application/json+problem:
               schema:
-                $ref: './problem.yaml'
+                allOf:
+                  - $ref: './problem.yaml'
+                  - type: object
+                    required:
+                      - type
+                    properties:
+                      type:
+                        $ref: '#/components/schemas/DownloadTranscript400ErrorCode'
               example:
-                type: "TRANSCRIPTION_109"
-                title: "Failed to download transcript"
+                type: "TRANSCRIPTION_124"
+                title: "Invalid transcription id"
                 status: 400
         '401':
           description: Unauthorised Error
@@ -1476,7 +1489,12 @@ components:
           type: integer
           description: The number of assigned transcript requests for a user with transcriber role.
           example: 3
-
+    DownloadTranscript400ErrorCode:
+      type: string
+      enum:
+        - "TRANSCRIPTION_124"
+      x-enum-varnames:
+        - BAD_REQUEST_TRANSCRIPTION_ID
     UpdateTranscriptions400ErrorCode:
       type: string
       enum:
@@ -1977,8 +1995,9 @@ components:
         - "TRANSCRIPTION_121"
         - "TRANSCRIPTION_122"
         - "TRANSCRIPTION_123"
+        - "TRANSCRIPTION_124"
       x-enum-varnames: [ FAILED_TO_VALIDATE_TRANSCRIPTION_REQUEST, TRANSCRIPTION_NOT_FOUND,  BAD_REQUEST_TRANSCRIPTION_STATUS, BAD_REQUEST_WORKFLOW_COMMENT, BAD_REQUEST_TRANSCRIPTION_TYPE, TRANSCRIPTION_WORKFLOW_ACTION_INVALID, BAD_REQUEST_TRANSCRIPTION_URGENCY, DUPLICATE_TRANSCRIPTION, FAILED_TO_ATTACH_TRANSCRIPT, AUDIO_NOT_FOUND, FAILED_TO_UPDATE_TRANSCRIPTIONS, TRANSCRIPTION_DOCUMENT_NOT_FOUND, TRANSCRIPTION_DOCUMENT_ALREADY_HIDDEN, TRANSCRIPTION_DOCUMENT_HIDE_ACTION_PAYLOAD_INCORRECT_USAGE, TRANSCRIPTION_DOCUMENT_SHOW_ACTION_PAYLOAD_INCORRECT_USAGE, TRANSCRIPTION_DOCUMENT_HIDE_ACTION_REASON_NOT_FOUND,
-                         TRANSCRIPTION_DOCUMENT_DELETE_NOT_SUPPORTED, TRANSCRIPTION_DOCUMENT_DELETION_ALREADY_APPROVED, TRANSCRIPTION_DOCUMENT_DELETION_CAN_NOT_APPROVE_OWN_REQUEST, TOO_MANY_RESULTS, TRANSCRIPTION_DOCUMENT_MARKED_FOR_DELETION_REASON_NOT_FOUND,FAILED_TO_UPLOAD_TRANSCRIPT ]
+                         TRANSCRIPTION_DOCUMENT_DELETE_NOT_SUPPORTED, TRANSCRIPTION_DOCUMENT_DELETION_ALREADY_APPROVED, TRANSCRIPTION_DOCUMENT_DELETION_CAN_NOT_APPROVE_OWN_REQUEST, TOO_MANY_RESULTS, TRANSCRIPTION_DOCUMENT_MARKED_FOR_DELETION_REASON_NOT_FOUND,FAILED_TO_UPLOAD_TRANSCRIPT,  BAD_REQUEST_TRANSCRIPTION_ID]
 
     TranscriptionsTitleErrors:
       type: string
@@ -2006,6 +2025,7 @@ components:
         - "Too many results"
         - "Transcription document marked for deletion reason not found"
         - "Failed to upload transcript"
+        - "Invalid transcription id"
 
       x-enum-varnames: [ FAILED_TO_VALIDATE_TRANSCRIPTION_REQUEST, TRANSCRIPTION_NOT_FOUND,  BAD_REQUEST_TRANSCRIPTION_STATUS, BAD_REQUEST_WORKFLOW_COMMENT, BAD_REQUEST_TRANSCRIPTION_TYPE, TRANSCRIPTION_WORKFLOW_ACTION_INVALID, BAD_REQUEST_TRANSCRIPTION_URGENCY, DUPLICATE_TRANSCRIPTION, FAILED_TO_ATTACH_TRANSCRIPT, AUDIO_NOT_FOUND, FAILED_TO_UPDATE_TRANSCRIPTIONS, TRANSCRIPTION_DOCUMENT_NOT_FOUND,  TRANSCRIPTION_DOCUMENT_ALREADY_HIDDEN, TRANSCRIPTION_DOCUMENT_HIDE_ACTION_PAYLOAD_INCORRECT_USAGE, TRANSCRIPTION_DOCUMENT_SHOW_ACTION_PAYLOAD_INCORRECT_USAGE,
-                         TRANSCRIPTION_DOCUMENT_HIDE_ACTION_REASON_NOT_FOUND, TRANSCRIPTION_DOCUMENT_HIDE_ACTION_REASON_MARKED_FOR_DELETION, TRANSCRIPTION_DOCUMENT_DELETE_NOT_SUPPORTED, TRANSCRIPTION_DOCUMENT_DELETION_ALREADY_APPROVED, TRANSCRIPTION_DOCUMENT_DELETION_CAN_NOT_APPROVE_OWN_REQUEST, TOO_MANY_RESULTS, TRANSCRIPTION_DOCUMENT_MARKED_FOR_DELETION_REASON_NOT_FOUND,FAILED_TO_UPLOAD_TRANSCRIPT ]
\ No newline at end of file
+                         TRANSCRIPTION_DOCUMENT_HIDE_ACTION_REASON_NOT_FOUND, TRANSCRIPTION_DOCUMENT_HIDE_ACTION_REASON_MARKED_FOR_DELETION, TRANSCRIPTION_DOCUMENT_DELETE_NOT_SUPPORTED, TRANSCRIPTION_DOCUMENT_DELETION_ALREADY_APPROVED, TRANSCRIPTION_DOCUMENT_DELETION_CAN_NOT_APPROVE_OWN_REQUEST, TOO_MANY_RESULTS, TRANSCRIPTION_DOCUMENT_MARKED_FOR_DELETION_REASON_NOT_FOUND,FAILED_TO_UPLOAD_TRANSCRIPT , BAD_REQUEST_TRANSCRIPTION_ID]
\ No newline at end of file
diff --git a/src/test/java/uk/gov/hmcts/darts/openapi/TranscriptionOpenApiContractTest.java b/src/test/java/uk/gov/hmcts/darts/openapi/TranscriptionOpenApiContractTest.java
new file mode 100644
index 00000000000..af7b89ab3f8
--- /dev/null
+++ b/src/test/java/uk/gov/hmcts/darts/openapi/TranscriptionOpenApiContractTest.java
@@ -0,0 +1,62 @@
+package uk.gov.hmcts.darts.openapi;
+
+import com.atlassian.oai.validator.OpenApiInteractionValidator;
+import com.atlassian.oai.validator.model.Request;
+import com.atlassian.oai.validator.model.SimpleRequest;
+import com.atlassian.oai.validator.report.ValidationReport;
+import org.junit.jupiter.api.Test;
+import uk.gov.hmcts.darts.util.ValidationConstants;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class TranscriptionOpenApiContractTest {
+
+    private static final OpenApiInteractionValidator VALIDATOR =
+        OpenApiInteractionValidator.createForSpecificationUrl(
+            TranscriptionOpenApiContractTest.class
+                .getResource("/openapi/transcriptions.yaml")
+                .toExternalForm()
+        ).build();
+
+    @Test
+    void openApi_ShouldReturnError_WhenNegativeTranscriptionIdUsed() {
+        Request request = SimpleRequest.Builder
+            .get("/transcriptions/-123/document")
+            .build();
+
+        ValidationReport report = VALIDATOR.validateRequest(request);
+
+        assertTrue(report.getMessages().stream()
+            .anyMatch(m -> m.getMessage().contains("Numeric instance is lower than the required " +
+                                                       "minimum (minimum: 1, found: -123)")));
+    }
+
+    @Test
+    void openApi_ShouldReturnError_WhenAboveMaximumTranscriptionIdUsed() {
+        String maxTranscriptionId = ValidationConstants.MaxValues.MAX_LONG_VALUE.toString();
+        String exceededTranscriptionId = maxTranscriptionId + "99";
+        Request request = SimpleRequest.Builder
+            .get("/transcriptions/" + exceededTranscriptionId + "/document")
+            .build();
+
+        ValidationReport report = VALIDATOR.validateRequest(request);
+
+        String expectedSubstring = "Numeric instance is greater than the required maximum (maximum: "
+            + maxTranscriptionId + ", found: " + exceededTranscriptionId + ")";
+
+        assertTrue(
+            report.getMessages().stream().anyMatch(m -> m.getMessage().equals(expectedSubstring))
+        );
+    }
+
+    @Test
+    void openApi_ShouldReturnNoError_WhenValidTranscriptionIdUsed() {
+        Request request = SimpleRequest.Builder
+            .get("/transcriptions/1000/document")
+            .build();
+
+        ValidationReport report = VALIDATOR.validateRequest(request);
+
+        assertTrue(report.getMessages().isEmpty(), "Expected no validation errors for a valid transcription_id");
+    }
+}
diff --git a/src/test/java/uk/gov/hmcts/darts/util/DataUtilTest.java b/src/test/java/uk/gov/hmcts/darts/util/DataUtilTest.java
index 5b59d80a7b4..3ad580dc05c 100644
--- a/src/test/java/uk/gov/hmcts/darts/util/DataUtilTest.java
+++ b/src/test/java/uk/gov/hmcts/darts/util/DataUtilTest.java
@@ -295,4 +295,35 @@ void toBooleanWithDefaultValue_shouldDefaultToValueSpecified() {
         assertThat(DataUtil.toBoolean(true)).isTrue();
         assertThat(DataUtil.toBoolean(false)).isFalse();
     }
+
+    @Test
+    void isWithinBounds_shouldReturnTrue_WhenValueIsWithinBounds() {
+        assertThat(DataUtil.isWithinBounds(5L, 1L, 10L)).isTrue();
+    }
+
+    @Test
+    void isWithinBounds_shouldReturnFalse_WhenValueIsBelowMin() {
+        assertThat(DataUtil.isWithinBounds(0L, 1L, 10L)).isFalse();
+    }
+
+    @Test
+    void isWithinBounds_shouldReturnFalse_WhenValueIsAboveMax() {
+        assertThat(DataUtil.isWithinBounds(11L, 1L, 10L)).isFalse();
+    }
+
+    @Test
+    void isWithinBounds_shouldReturnTrue_WhenValueIsEqualToMin() {
+        assertThat(DataUtil.isWithinBounds(1L, 1L, 10L)).isTrue();
+    }
+
+    @Test
+    void isWithinBounds_shouldReturnTrue_WhenValueIsEqualToMax() {
+        assertThat(DataUtil.isWithinBounds(10L, 1L, 10L)).isTrue();
+    }
+
+    @Test
+    void isWithinBounds_shouldReturnFalseWhenValueIsNull() {
+        assertThat(DataUtil.isWithinBounds(null, 1L, 10L)).isFalse();
+    }
+
 }