diff --git a/lib/js-api/src/fetchHttpClient.ts b/lib/js-api/src/fetchHttpClient.ts
index 03488b45d1..1af869b34b 100644
--- a/lib/js-api/src/fetchHttpClient.ts
+++ b/lib/js-api/src/fetchHttpClient.ts
@@ -367,7 +367,12 @@ export class FetchHttpClient implements HttpClient {
             const normalizedParams = FetchHttpClient.normalizeParams(formParams);
             const formData = new FormData();
             for (const [key, value] of Object.entries(normalizedParams)) {
-                formData.append(key, value as any);
+                const { data, filename } = FetchHttpClient.toFormDataValue(value);
+                if (filename) {
+                    formData.append(key, data, filename);
+                } else {
+                    formData.append(key, data);
+                }
             }
             return formData;
         }
@@ -524,4 +529,24 @@ export class FetchHttpClient implements HttpClient {
         }
         return false;
     }
+
+    private static toFormDataValue(value: any): { data: any; filename?: string } {
+        if (value && typeof value === 'object' && value.path && typeof value.path === 'string' && !(value instanceof Blob)) {
+            try {
+                const nodeFs = Function('return require("fs")')();
+                const nodePath = Function('return require("path")')();
+                const buffer = nodeFs.readFileSync(value.path);
+                const filename: string = nodePath.basename(value.path);
+                return { data: new Blob([buffer]), filename };
+            } catch {
+                return { data: value };
+            }
+        }
+
+        if (typeof Buffer === 'function' && value instanceof Buffer) {
+            return { data: new Blob([value]) };
+        }
+
+        return { data: value };
+    }
 }
diff --git a/lib/js-api/test/fetchHttpClient.spec.ts b/lib/js-api/test/fetchHttpClient.spec.ts
index d0e1779ab9..6692705bcd 100644
--- a/lib/js-api/test/fetchHttpClient.spec.ts
+++ b/lib/js-api/test/fetchHttpClient.spec.ts
@@ -19,6 +19,8 @@
 import { FetchHttpClient } from '../src/fetchHttpClient';
 import { EventEmitter } from 'eventemitter3';
 import { getGlobalMockAgent, mockHost } from './mockObjects/base.mock';
+import * as fs from 'fs';
+import * as path from 'path';
 
 describe('FetchHttpClient', () => {
     const host = 'https://127.0.0.1:8080';
@@ -1097,4 +1099,123 @@ describe('FetchHttpClient', () => {
             ]);
         });
     });
+
+    describe('multipart form data upload', () => {
+        let originalFunction: typeof global.Function;
+
+        beforeEach(() => {
+            originalFunction = global.Function;
+            global.Function = ((code: string) => {
+                if (code.includes('require')) {
+                    return () => require(/"([^"]+)"/.exec(code)?.[1] || '');
+                }
+                return originalFunction(code);
+            }) as FunctionConstructor;
+        });
+
+        afterEach(() => {
+            global.Function = originalFunction;
+        });
+
+        it('should send Blob when form param is a Blob', async () => {
+            mockHost(host).post('/api/upload').reply(200, { success: true });
+
+            const blob = new Blob(['content'], { type: 'text/plain' });
+            const result = await client.post(
+                host + '/api/upload',
+                {
+                    httpMethod: 'POST',
+                    queryParams: {},
+                    headerParams: {},
+                    formParams: { file: blob },
+                    bodyParam: null,
+                    contentType: 'multipart/form-data',
+                    accept: 'application/json',
+                    responseType: null,
+                    returnType: null
+                },
+                defaultSecurityOptions,
+                emitters
+            );
+
+            expect(result).toEqual({ success: true });
+        });
+
+        it('should convert Buffer to Blob when form param is a Buffer', async () => {
+            mockHost(host).post('/api/upload').reply(200, { success: true });
+
+            const buffer = Buffer.from('file content');
+            const result = await client.post(
+                host + '/api/upload',
+                {
+                    httpMethod: 'POST',
+                    queryParams: {},
+                    headerParams: {},
+                    formParams: { file: buffer },
+                    bodyParam: null,
+                    contentType: 'multipart/form-data',
+                    accept: 'application/json',
+                    responseType: null,
+                    returnType: null
+                },
+                defaultSecurityOptions,
+                emitters
+            );
+
+            expect(result).toEqual({ success: true });
+        });
+
+        it('should read file and send as Blob when form param has .path property', async () => {
+            mockHost(host).post('/api/upload').reply(200, { success: true });
+
+            const tmpFile = path.join(__dirname, '__test_upload__.txt');
+            fs.writeFileSync(tmpFile, 'test content');
+
+            try {
+                const result = await client.post(
+                    host + '/api/upload',
+                    {
+                        httpMethod: 'POST',
+                        queryParams: {},
+                        headerParams: {},
+                        formParams: { file: { path: tmpFile } },
+                        bodyParam: null,
+                        contentType: 'multipart/form-data',
+                        accept: 'application/json',
+                        responseType: null,
+                        returnType: null
+                    },
+                    defaultSecurityOptions,
+                    emitters
+                );
+
+                expect(result).toEqual({ success: true });
+            } finally {
+                fs.unlinkSync(tmpFile);
+            }
+        });
+
+        it('should pass through string values when form params are strings', async () => {
+            mockHost(host).post('/api/upload').reply(200, { success: true });
+
+            const result = await client.post(
+                host + '/api/upload',
+                {
+                    httpMethod: 'POST',
+                    queryParams: {},
+                    headerParams: {},
+                    formParams: { name: 'test-file', description: 'a test' },
+                    bodyParam: null,
+                    contentType: 'multipart/form-data',
+                    accept: 'application/json',
+                    responseType: null,
+                    returnType: null
+                },
+                defaultSecurityOptions,
+                emitters
+            );
+
+            expect(result).toEqual({ success: true });
+        });
+    });
 });