diff --git a/common/src/main/java/stirling/software/common/model/api/PDFFile.java b/common/src/main/java/stirling/software/common/model/api/PDFFile.java
index 59604630b..44f7c4781 100644
--- a/common/src/main/java/stirling/software/common/model/api/PDFFile.java
+++ b/common/src/main/java/stirling/software/common/model/api/PDFFile.java
@@ -19,7 +19,6 @@ public class PDFFile {
             contentMediaType = "application/pdf",
             format = "binary",
             requiredMode = Schema.RequiredMode.REQUIRED)
-    @NotNull
     @NotNull(message = "PDF file is required")
     private MultipartFile fileInput;
 
diff --git a/common/src/main/java/stirling/software/common/model/api/converters/EmlToPdfRequest.java b/common/src/main/java/stirling/software/common/model/api/converters/EmlToPdfRequest.java
index 32dda8501..11b409ae3 100644
--- a/common/src/main/java/stirling/software/common/model/api/converters/EmlToPdfRequest.java
+++ b/common/src/main/java/stirling/software/common/model/api/converters/EmlToPdfRequest.java
@@ -17,7 +17,6 @@ public class EmlToPdfRequest {
             description = "The input EML email file",
             format = "binary",
             requiredMode = Schema.RequiredMode.REQUIRED)
-    @NotNull
     @NotNull(message = "EML file is required")
     private MultipartFile fileInput;
 
diff --git a/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/HandleDataRequest.java b/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/HandleDataRequest.java
index d3b9fc823..79e38075b 100644
--- a/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/HandleDataRequest.java
+++ b/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/HandleDataRequest.java
@@ -5,6 +5,7 @@ import org.springframework.web.multipart.MultipartFile;
 import io.swagger.v3.oas.annotations.media.Schema;
 
 import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
 
 import lombok.Data;
 import lombok.EqualsAndHashCode;
@@ -14,8 +15,8 @@ import lombok.EqualsAndHashCode;
 public class HandleDataRequest {
 
     @Schema(description = "The input files", requiredMode = Schema.RequiredMode.REQUIRED)
-    @NotNull
     @NotNull(message = "File input is required")
+    @Size(min = 1)
     private MultipartFile[] fileInput;
 
     @Schema(
diff --git a/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/MultiplePDFFiles.java b/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/MultiplePDFFiles.java
index 58268b7b4..dbdce185f 100644
--- a/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/MultiplePDFFiles.java
+++ b/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/MultiplePDFFiles.java
@@ -5,6 +5,7 @@ import org.springframework.web.multipart.MultipartFile;
 import io.swagger.v3.oas.annotations.media.Schema;
 
 import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
 
 import lombok.Data;
 import lombok.EqualsAndHashCode;
@@ -13,7 +14,7 @@ import lombok.EqualsAndHashCode;
 @EqualsAndHashCode
 public class MultiplePDFFiles {
     @Schema(description = "The input PDF files", requiredMode = Schema.RequiredMode.REQUIRED)
-    @NotNull
     @NotNull(message = "File input is required")
+    @Size(min = 1)
     private MultipartFile[] fileInput;
 }
diff --git a/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/converters/ConvertToPdfRequest.java b/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/converters/ConvertToPdfRequest.java
index 577e08d8f..bb69c5bad 100644
--- a/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/converters/ConvertToPdfRequest.java
+++ b/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/converters/ConvertToPdfRequest.java
@@ -5,6 +5,7 @@ import org.springframework.web.multipart.MultipartFile;
 import io.swagger.v3.oas.annotations.media.Schema;
 
 import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
 
 import lombok.Data;
 import lombok.EqualsAndHashCode;
@@ -16,8 +17,8 @@ public class ConvertToPdfRequest {
     @Schema(
             description = "The input images to be converted to a PDF file",
             requiredMode = Schema.RequiredMode.REQUIRED)
-    @NotNull
     @NotNull(message = "File input is required")
+    @Size(min = 1)
     private MultipartFile[] fileInput;
 
     @Schema(
diff --git a/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/general/OverlayPdfsRequest.java b/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/general/OverlayPdfsRequest.java
index f06f38258..9387eaa63 100644
--- a/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/general/OverlayPdfsRequest.java
+++ b/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/general/OverlayPdfsRequest.java
@@ -5,6 +5,7 @@ import org.springframework.web.multipart.MultipartFile;
 import io.swagger.v3.oas.annotations.media.Schema;
 
 import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
 
 import lombok.Data;
 import lombok.EqualsAndHashCode;
@@ -20,8 +21,8 @@ public class OverlayPdfsRequest extends PDFFile {
                     "An array of PDF files to be used as overlays on the base PDF. The order in"
                             + " these files is applied based on the selected mode.",
             requiredMode = Schema.RequiredMode.REQUIRED)
-    @NotNull
     @NotNull(message = "Overlay files are required")
+    @Size(min = 1)
     private MultipartFile[] overlayFiles;
 
     @Schema(
diff --git a/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/misc/AddAttachmentRequest.java b/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/misc/AddAttachmentRequest.java
index 17a54bdd5..6b3dcb0df 100644
--- a/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/misc/AddAttachmentRequest.java
+++ b/stirling-pdf/src/main/java/stirling/software/SPDF/model/api/misc/AddAttachmentRequest.java
@@ -7,6 +7,7 @@ import org.springframework.web.multipart.MultipartFile;
 import io.swagger.v3.oas.annotations.media.Schema;
 
 import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
 
 import lombok.Data;
 import lombok.EqualsAndHashCode;
@@ -22,5 +23,6 @@ public class AddAttachmentRequest extends PDFFile {
             requiredMode = Schema.RequiredMode.REQUIRED,
             format = "binary")
     @NotNull(message = "Attachments are required")
+    @Size(min = 1)
     private List<MultipartFile> attachments;
 }