diff --git a/src/bun.js/ConsoleObject.zig b/src/bun.js/ConsoleObject.zig
index f9d540ed11..491689ecc4 100644
--- a/src/bun.js/ConsoleObject.zig
+++ b/src/bun.js/ConsoleObject.zig
@@ -1629,11 +1629,11 @@ pub const Formatter = struct {
                         },
 
                         .j => {
-                            // JSON.stringify the value
+                            // JSON.stringify the value using FastStringifier for SIMD optimization
                             var str = bun.String.empty;
                             defer str.deref();
 
-                            try next_value.jsonStringify(global, 0, &str);
+                            try next_value.jsonStringifyFast(global, &str);
                             this.addForNewLine(str.length());
                             writer.print("{f}", .{str});
                         },
diff --git a/src/bun.js/api/JSTranspiler.zig b/src/bun.js/api/JSTranspiler.zig
index 86814d6dee..2524468d1a 100644
--- a/src/bun.js/api/JSTranspiler.zig
+++ b/src/bun.js/api/JSTranspiler.zig
@@ -165,7 +165,8 @@ pub const Config = struct {
                 }
 
                 if (!kind.isStringLike()) {
-                    try tsconfig.jsonStringify(globalThis, 0, &out);
+                    // Use jsonStringifyFast for SIMD-optimized serialization
+                    try tsconfig.jsonStringifyFast(globalThis, &out);
                 } else {
                     out = try tsconfig.toBunString(globalThis);
                 }
@@ -204,7 +205,8 @@ pub const Config = struct {
                 defer out.deref();
                 // TODO: write a converter between JSC types and Bun AST types
                 if (is_object) {
-                    try macros.jsonStringify(globalThis, 0, &out);
+                    // Use jsonStringifyFast for SIMD-optimized serialization
+                    try macros.jsonStringifyFast(globalThis, &out);
                 } else {
                     out = try macros.toBunString(globalThis);
                 }
diff --git a/src/bun.js/ipc.zig b/src/bun.js/ipc.zig
index 5ac9975619..fa00ec05a5 100644
--- a/src/bun.js/ipc.zig
+++ b/src/bun.js/ipc.zig
@@ -229,7 +229,9 @@ const json = struct {
 
     pub fn serialize(writer: *bun.io.StreamBuffer, global: *jsc.JSGlobalObject, value: JSValue, is_internal: IsInternal) !usize {
         var out: bun.String = undefined;
-        try value.jsonStringify(global, 0, &out);
+        // Use jsonStringifyFast which passes undefined for the space parameter,
+        // triggering JSC's SIMD-optimized FastStringifier code path.
+        try value.jsonStringifyFast(global, &out);
         defer out.deref();
 
         if (out.tag == .Dead) return IPCSerializationError.SerializationFailed;
diff --git a/src/bun.js/test/jest.zig b/src/bun.js/test/jest.zig
index cb913c812d..1acacb9994 100644
--- a/src/bun.js/test/jest.zig
+++ b/src/bun.js/test/jest.zig
@@ -430,7 +430,8 @@ pub fn formatLabel(globalThis: *JSGlobalObject, label: string, function_args: []
                 'j', 'o' => {
                     var str = bun.String.empty;
                     defer str.deref();
-                    try current_arg.jsonStringify(globalThis, 0, &str);
+                    // Use jsonStringifyFast for SIMD-optimized serialization
+                    try current_arg.jsonStringifyFast(globalThis, &str);
                     const owned_slice = bun.handleOom(str.toOwnedSlice(allocator));
                     defer allocator.free(owned_slice);
                     bun.handleOom(list.appendSlice(owned_slice));
diff --git a/src/sql/mysql/MySQLTypes.zig b/src/sql/mysql/MySQLTypes.zig
index 0280718592..a4efe2fdba 100644
--- a/src/sql/mysql/MySQLTypes.zig
+++ b/src/sql/mysql/MySQLTypes.zig
@@ -486,7 +486,8 @@ pub const Value = union(enum) {
 
             .MYSQL_TYPE_JSON => {
                 var str: bun.String = bun.String.empty;
-                try value.jsonStringify(globalObject, 0, &str);
+                // Use jsonStringifyFast for SIMD-optimized serialization
+                try value.jsonStringifyFast(globalObject, &str);
                 defer str.deref();
                 return Value{ .string = str.toUTF8(bun.default_allocator) };
             },
diff --git a/src/sql/postgres/PostgresRequest.zig b/src/sql/postgres/PostgresRequest.zig
index 775ab536c9..c06bc28c19 100644
--- a/src/sql/postgres/PostgresRequest.zig
+++ b/src/sql/postgres/PostgresRequest.zig
@@ -101,7 +101,8 @@ pub fn writeBind(
             .jsonb, .json => {
                 var str = bun.String.empty;
                 defer str.deref();
-                try value.jsonStringify(globalObject, 0, &str);
+                // Use jsonStringifyFast for SIMD-optimized serialization
+                try value.jsonStringifyFast(globalObject, &str);
                 const slice = str.toUTF8WithoutRef(bun.default_allocator);
                 defer slice.deinit();
                 const l = try writer.length();