diff --git a/tests/entrypoints/openai/test_chat.py b/tests/entrypoints/openai/test_chat.py
index 47c521a9b5eb5..5e6499d8f563c 100644
--- a/tests/entrypoints/openai/test_chat.py
+++ b/tests/entrypoints/openai/test_chat.py
@@ -17,6 +17,8 @@
 # any model with a chat template should work here
 MODEL_NAME = "HuggingFaceH4/zephyr-7b-beta"
 
+GUIDED_DECODING_BACKENDS = ["outlines", "lm-format-enforcer", "xgrammar"]
+
 
 @pytest.fixture(scope="module")
 def server(zephyr_lora_files, zephyr_lora_added_tokens_files):  # noqa: F811
@@ -464,8 +466,7 @@ async def test_chat_completion_stream_options(client: openai.AsyncOpenAI,
 # will fail on the second `guided_decoding_backend` even when I swap their order
 # (ref: https://github.com/vllm-project/vllm/pull/5526#issuecomment-2173772256)
 @pytest.mark.asyncio
-@pytest.mark.parametrize("guided_decoding_backend",
-                         ["outlines", "lm-format-enforcer"])
+@pytest.mark.parametrize("guided_decoding_backend", GUIDED_DECODING_BACKENDS)
 async def test_guided_choice_chat(client: openai.AsyncOpenAI,
                                   guided_decoding_backend: str,
                                   sample_guided_choice):
@@ -506,8 +507,7 @@ async def test_guided_choice_chat(client: openai.AsyncOpenAI,
 
 
 @pytest.mark.asyncio
-@pytest.mark.parametrize("guided_decoding_backend",
-                         ["outlines", "lm-format-enforcer"])
+@pytest.mark.parametrize("guided_decoding_backend", GUIDED_DECODING_BACKENDS)
 async def test_guided_json_chat(client: openai.AsyncOpenAI,
                                 guided_decoding_backend: str,
                                 sample_json_schema):
@@ -554,8 +554,7 @@ async def test_guided_json_chat(client: openai.AsyncOpenAI,
 
 
 @pytest.mark.asyncio
-@pytest.mark.parametrize("guided_decoding_backend",
-                         ["outlines", "lm-format-enforcer"])
+@pytest.mark.parametrize("guided_decoding_backend", GUIDED_DECODING_BACKENDS)
 async def test_guided_regex_chat(client: openai.AsyncOpenAI,
                                  guided_decoding_backend: str, sample_regex):
     messages = [{
@@ -613,8 +612,7 @@ async def test_guided_decoding_type_error(client: openai.AsyncOpenAI):
 
 
 @pytest.mark.asyncio
-@pytest.mark.parametrize("guided_decoding_backend",
-                         ["outlines", "lm-format-enforcer"])
+@pytest.mark.parametrize("guided_decoding_backend", GUIDED_DECODING_BACKENDS)
 async def test_guided_choice_chat_logprobs(client: openai.AsyncOpenAI,
                                            guided_decoding_backend: str,
                                            sample_guided_choice):
@@ -646,8 +644,7 @@ async def test_guided_choice_chat_logprobs(client: openai.AsyncOpenAI,
 
 
 @pytest.mark.asyncio
-@pytest.mark.parametrize("guided_decoding_backend",
-                         ["outlines", "lm-format-enforcer"])
+@pytest.mark.parametrize("guided_decoding_backend", GUIDED_DECODING_BACKENDS)
 async def test_named_tool_use(client: openai.AsyncOpenAI,
                               guided_decoding_backend: str,
                               sample_json_schema):
@@ -681,7 +678,8 @@ async def test_named_tool_use(client: openai.AsyncOpenAI,
             "function": {
                 "name": "dummy_function_name"
             }
-        })
+        },
+        extra_body=dict(guided_decoding_backend=guided_decoding_backend))
     message = chat_completion.choices[0].message
     assert len(message.content) == 0
     json_string = message.tool_calls[0].function.arguments
@@ -716,6 +714,7 @@ async def test_named_tool_use(client: openai.AsyncOpenAI,
                 "name": "dummy_function_name"
             }
         },
+        extra_body=dict(guided_decoding_backend=guided_decoding_backend),
         stream=True)
 
     output = []
@@ -738,10 +737,8 @@ async def test_named_tool_use(client: openai.AsyncOpenAI,
 
 
 @pytest.mark.asyncio
-@pytest.mark.parametrize("guided_decoding_backend", ["outlines"])
-async def test_required_tool_use_not_yet_supported(
-        client: openai.AsyncOpenAI, guided_decoding_backend: str,
-        sample_json_schema):
+async def test_required_tool_use_not_yet_supported(client: openai.AsyncOpenAI,
+                                                   sample_json_schema):
     messages = [{
         "role": "system",
         "content": "you are a helpful assistant"
@@ -785,9 +782,7 @@ async def test_required_tool_use_not_yet_supported(
 
 
 @pytest.mark.asyncio
-@pytest.mark.parametrize("guided_decoding_backend", ["outlines"])
 async def test_inconsistent_tool_choice_and_tools(client: openai.AsyncOpenAI,
-                                                  guided_decoding_backend: str,
                                                   sample_json_schema):
     messages = [{
         "role": "system",