diff --git a/scripts/js-api-tests.js b/scripts/js-api-tests.js
index 3e2db53f5dc..048e8c7092b 100644
--- a/scripts/js-api-tests.js
+++ b/scripts/js-api-tests.js
@@ -2217,11 +2217,14 @@ let serveTests = {
       onRequest = resolve;
     });
 
-    const result = await esbuild.serve({ onRequest }, {
+    const result = await esbuild.serve({
+      host: '127.0.0.1',
+      onRequest,
+    }, {
       entryPoints: [input],
       format: 'esm',
     })
-    assert.strictEqual(result.host, '0.0.0.0');
+    assert.strictEqual(result.host, '127.0.0.1');
     assert.strictEqual(typeof result.port, 'number');
 
     const buffer = await fetch(result.host, result.port, '/in.js')
@@ -2247,12 +2250,15 @@ let serveTests = {
       onRequest = resolve;
     });
 
-    const result = await esbuild.serve({ onRequest }, {
+    const result = await esbuild.serve({
+      host: '127.0.0.1',
+      onRequest,
+    }, {
       entryPoints: [input],
       format: 'esm',
       outfile: 'out.js',
     })
-    assert.strictEqual(result.host, '0.0.0.0');
+    assert.strictEqual(result.host, '127.0.0.1');
     assert.strictEqual(typeof result.port, 'number');
 
     const buffer = await fetch(result.host, result.port, '/out.js')
@@ -2298,13 +2304,14 @@ let serveTests = {
     })();
 
     const result = await esbuild.serve({
+      host: '127.0.0.1',
       onRequest: args => onRequest(args),
       servedir: wwwDir,
     }, {
       entryPoints: [input],
       format: 'esm',
     })
-    assert.strictEqual(result.host, '0.0.0.0');
+    assert.strictEqual(result.host, '127.0.0.1');
     assert.strictEqual(typeof result.port, 'number');
 
     let promise, buffer, req;
@@ -2386,6 +2393,7 @@ let serveTests = {
     })();
 
     const result = await esbuild.serve({
+      host: '127.0.0.1',
       onRequest: args => onRequest(args),
       servedir: wwwDir,
     }, {
@@ -2393,7 +2401,7 @@ let serveTests = {
       format: 'esm',
       outdir: outputDir,
     })
-    assert.strictEqual(result.host, '0.0.0.0');
+    assert.strictEqual(result.host, '127.0.0.1');
     assert.strictEqual(typeof result.port, 'number');
 
     let promise, buffer, req;
@@ -2439,11 +2447,12 @@ let serveTests = {
     })();
 
     const result = await esbuild.serve({
+      host: '127.0.0.1',
       onRequest: args => onRequest(args),
       servedir: testDir,
     }, {
     })
-    assert.strictEqual(result.host, '0.0.0.0');
+    assert.strictEqual(result.host, '127.0.0.1');
     assert.strictEqual(typeof result.port, 'number');
 
     let promise, buffer, req;