From d195316fa0544b159d2cec6c5a82b503d72f1230 Mon Sep 17 00:00:00 2001
From: lohit-bruno <lohit@usebruno.com>
Date: Tue, 6 Oct 2026 16:46:09 +0530
Subject: [PATCH] fix(bruno-request): set Buffer bodies from req.setBody as-is
 under a JSON Content-Type

---
 packages/bruno-js/src/bruno-request.js                    | 3 ++-
 .../bruno-js/tests/script-runtime-request-body.spec.js    | 8 ++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/packages/bruno-js/src/bruno-request.js b/packages/bruno-js/src/bruno-request.js
index 361feece6..242fd18f2 100644
--- a/packages/bruno-js/src/bruno-request.js
+++ b/packages/bruno-js/src/bruno-request.js
@@ -204,9 +204,10 @@ class BrunoRequest {
    *  - We set the body property as the data itself
    *
    * If the user wants to override this behavior, they can pass the raw option as true
+   * A Buffer is always set as-is, since it already holds the exact bytes to send
    */
   setBody(data, options = {}) {
-    if (options.raw) {
+    if (options.raw || Buffer.isBuffer(data)) {
       this.req.data = data;
       this.body = data;
       return;
diff --git a/packages/bruno-js/tests/script-runtime-request-body.spec.js b/packages/bruno-js/tests/script-runtime-request-body.spec.js
index 3bb2a312e..81dcb9a77 100644
--- a/packages/bruno-js/tests/script-runtime-request-body.spec.js
+++ b/packages/bruno-js/tests/script-runtime-request-body.spec.js
@@ -42,6 +42,14 @@ describe.each(['nodevm', 'quickjs'])('req.setBody() in a pre-request script on %
     expect(request.data).toStrictEqual(Buffer.from(BINARY_BYTES));
   });
 
+  it('keeps every byte of a Buffer body set without options when Content-Type is application/json', async () => {
+    const request = makeRequest({ headers: { 'content-type': 'application/json' } });
+
+    await runRequestScript(runtime, `req.setBody(Buffer.from(${JSON.stringify(BINARY_BYTES)}))`, request);
+
+    expect(request.data).toStrictEqual(Buffer.from(BINARY_BYTES));
+  });
+
   it('keeps only the bytes inside a sliced Buffer body', async () => {
     const request = makeRequest();