From 2af1a2ece843176ce559547bf674bb51ca0345a1 Mon Sep 17 00:00:00 2001
From: breken-ai <312387581+breken-ai@users.noreply.github.com>
Date: Fri, 25 Sep 2026 20:40:23 -0700
Subject: [PATCH] fix(http): keep existing query on web params

The web CapacitorHttp request joined params with '?' even when the url already had a query string, producing url?a=1?b=2. Use '&' in that case, matching Android and iOS.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
---
 core/src/core-plugins.ts    |  3 ++-
 core/src/tests/http.spec.ts | 42 +++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100644 core/src/tests/http.spec.ts

diff --git a/core/src/core-plugins.ts b/core/src/core-plugins.ts
index a1efe9c901..2ed3d0abce 100644
--- a/core/src/core-plugins.ts
+++ b/core/src/core-plugins.ts
@@ -404,7 +404,8 @@ export class CapacitorHttpPluginWeb extends WebPlugin implements CapacitorHttpPl
   async request(options: HttpOptions): Promise<HttpResponse> {
     const requestInit = buildRequestInit(options, options.webFetchExtra);
     const urlParams = buildUrlParams(options.params, options.shouldEncodeUrlParams);
-    const url = urlParams ? `${options.url}?${urlParams}` : options.url;
+    const separator = options.url.includes('?') ? '&' : '?';
+    const url = urlParams ? `${options.url}${separator}${urlParams}` : options.url;
 
     const response = await fetch(url, requestInit);
     const contentType = response.headers.get('content-type') || '';
diff --git a/core/src/tests/http.spec.ts b/core/src/tests/http.spec.ts
new file mode 100644
index 0000000000..290c2d64a8
--- /dev/null
+++ b/core/src/tests/http.spec.ts
@@ -0,0 +1,42 @@
+/**
+ * @jest-environment jsdom
+ */
+
+import { CapacitorHttpPluginWeb } from '../core-plugins';
+
+describe('CapacitorHttpPluginWeb', () => {
+  const originalFetch = (globalThis as any).fetch;
+  let fetchMock: jest.Mock;
+
+  beforeEach(() => {
+    fetchMock = jest.fn(async (url: string) => ({
+      ok: true,
+      status: 200,
+      url,
+      headers: {
+        get: () => 'text/plain',
+        forEach: () => undefined,
+      },
+      text: async () => 'ok',
+    }));
+    (globalThis as any).fetch = fetchMock;
+  });
+
+  afterEach(() => {
+    (globalThis as any).fetch = originalFetch;
+  });
+
+  it('appends params to a url without a query string', async () => {
+    const http = new CapacitorHttpPluginWeb();
+    await http.get({ url: 'https://example.com/api', params: { b: '2' } });
+
+    expect(fetchMock.mock.calls[0][0]).toEqual('https://example.com/api?b=2');
+  });
+
+  it('keeps the existing query string when adding params', async () => {
+    const http = new CapacitorHttpPluginWeb();
+    await http.get({ url: 'https://example.com/api?a=1', params: { b: '2' } });
+
+    expect(fetchMock.mock.calls[0][0]).toEqual('https://example.com/api?a=1&b=2');
+  });
+});