diff --git a/app/core/src/main/java/stirling/software/SPDF/controller/api/pipeline/PipelineProcessor.java b/app/core/src/main/java/stirling/software/SPDF/controller/api/pipeline/PipelineProcessor.java
index f3a926de8..a0bb5b66b 100644
--- a/app/core/src/main/java/stirling/software/SPDF/controller/api/pipeline/PipelineProcessor.java
+++ b/app/core/src/main/java/stirling/software/SPDF/controller/api/pipeline/PipelineProcessor.java
@@ -18,10 +18,10 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.core.io.FileSystemResource;
 import org.springframework.core.io.Resource;
 import org.springframework.http.*;
-import org.springframework.http.converter.FormHttpMessageConverter;
 import org.springframework.stereotype.Service;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.RequestCallback;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.multipart.MultipartFile;
 
@@ -287,17 +287,19 @@ public class PipelineProcessor {
         // Set up headers, including API key
         HttpHeaders headers = new HttpHeaders();
         String apiKey = getApiKeyForUser();
-        headers.add("X-API-KEY", apiKey);
-        headers.setContentType(MediaType.MULTIPART_FORM_DATA);
+        if (apiKey != null && !apiKey.isEmpty()) {
+            headers.add("X-API-KEY", apiKey);
+        }
 
+        // Let the message converter set the multipart boundary/content type
+        HttpEntity<MultiValueMap<String, Object>> entity = new HttpEntity<>(body, headers);
+
+        RequestCallback requestCallback =
+                restTemplate.httpEntityCallback(entity, Resource.class /* response type hint */);
         return restTemplate.execute(
                 url,
                 HttpMethod.POST,
-                request -> {
-                    request.getHeaders().putAll(headers);
-                    new FormHttpMessageConverter()
-                            .write(body, MediaType.MULTIPART_FORM_DATA, request);
-                },
+                requestCallback,
                 response -> {
                     try {
                         TempFile tempFile = tempFileManager.createManagedTempFile("pipeline");
diff --git a/app/core/src/test/java/stirling/software/SPDF/controller/api/pipeline/PipelineProcessorTest.java b/app/core/src/test/java/stirling/software/SPDF/controller/api/pipeline/PipelineProcessorTest.java
index 0811b7de6..d58770f45 100644
--- a/app/core/src/test/java/stirling/software/SPDF/controller/api/pipeline/PipelineProcessorTest.java
+++ b/app/core/src/test/java/stirling/software/SPDF/controller/api/pipeline/PipelineProcessorTest.java
@@ -4,6 +4,8 @@ import static org.junit.jupiter.api.Assertions.*;
 import static org.mockito.ArgumentMatchers.*;
 import static org.mockito.Mockito.*;
 
+import java.io.ByteArrayInputStream;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.List;
@@ -13,12 +15,16 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
+import org.mockito.MockedConstruction;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.FileSystemResource;
 import org.springframework.core.io.Resource;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
 
 import jakarta.servlet.ServletContext;
 
@@ -126,6 +132,90 @@ class PipelineProcessorTest {
         Files.deleteIfExists(tempPath);
     }
 
+    @Test
+    void sendWebRequestDoesNotForceContentType() throws Exception {
+        MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
+        body.add(
+                "fileInput",
+                new ByteArrayResource("data".getBytes(StandardCharsets.UTF_8)) {
+                    @Override
+                    public String getFilename() {
+                        return "input.pdf";
+                    }
+                });
+
+        Path tempPath = Files.createTempFile("pipeline-test", ".tmp");
+        var tempFile = mock(stirling.software.common.util.TempFile.class);
+        when(tempFile.getPath()).thenReturn(tempPath);
+        when(tempFile.getFile()).thenReturn(tempPath.toFile());
+        when(tempFileManager.createManagedTempFile("pipeline")).thenReturn(tempFile);
+
+        var capturedHeaders = new org.springframework.http.HttpHeaders[1];
+
+        try (MockedConstruction<org.springframework.web.client.RestTemplate> ignored =
+                mockConstruction(
+                        org.springframework.web.client.RestTemplate.class,
+                        (mock, context) -> {
+                            when(mock.httpEntityCallback(any(), eq(Resource.class)))
+                                    .thenAnswer(
+                                            invocation -> {
+                                                var entity = invocation.getArgument(0);
+                                                capturedHeaders[0] =
+                                                        ((org.springframework.http.HttpEntity<?>)
+                                                                        entity)
+                                                                .getHeaders();
+                                                return (org.springframework.web.client
+                                                                .RequestCallback)
+                                                        request -> {};
+                                            });
+
+                            when(mock.execute(
+                                            anyString(),
+                                            eq(org.springframework.http.HttpMethod.POST),
+                                            any(),
+                                            any()))
+                                    .thenAnswer(
+                                            invocation -> {
+                                                @SuppressWarnings("unchecked")
+                                                var extractor =
+                                                        (org.springframework.web.client
+                                                                                .ResponseExtractor<
+                                                                        ResponseEntity<Resource>>)
+                                                                invocation.getArgument(3);
+                                                ClientHttpResponse response =
+                                                        mock(ClientHttpResponse.class);
+                                                when(response.getBody())
+                                                        .thenReturn(
+                                                                new ByteArrayInputStream(
+                                                                        "ok"
+                                                                                .getBytes(
+                                                                                        StandardCharsets
+                                                                                                .UTF_8)));
+                                                var headers =
+                                                        new org.springframework.http.HttpHeaders();
+                                                headers.add(
+                                                        org.springframework.http.HttpHeaders
+                                                                .CONTENT_DISPOSITION,
+                                                        "attachment; filename=\"out.pdf\"");
+                                                when(response.getHeaders()).thenReturn(headers);
+                                                lenient()
+                                                        .when(response.getStatusCode())
+                                                        .thenReturn(HttpStatus.OK);
+                                                return extractor.extractData(response);
+                                            });
+                        })) {
+            ResponseEntity<Resource> response =
+                    pipelineProcessor.sendWebRequest("http://localhost/api", body);
+
+            assertNotNull(response);
+            assertEquals(HttpStatus.OK, response.getStatusCode());
+            assertNotNull(response.getBody());
+            assertNull(capturedHeaders[0].getContentType());
+        } finally {
+            Files.deleteIfExists(tempPath);
+        }
+    }
+
     private static class MyFileByteArrayResource extends ByteArrayResource {
         public MyFileByteArrayResource() {
             super("data".getBytes());