diff --git a/pyproject.toml b/pyproject.toml
index 499db6e..a17c384 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,6 +38,7 @@ dependencies = { file = "requirements/_.txt" }
 
 [tool.setuptools.dynamic.optional-dependencies]
 dev = { file = "requirements/dev.txt" }
+speed = { file = "requirements/speed.txt" }
 
 [tool.setuptools.packages.find]
 where = ["src"]
diff --git a/requirements/speed.txt b/requirements/speed.txt
new file mode 100644
index 0000000..37c6a01
--- /dev/null
+++ b/requirements/speed.txt
@@ -0,0 +1 @@
+ujson~=5.8.0
\ No newline at end of file
diff --git a/src/pyrmv/raw/__init__.py b/src/pyrmv/raw/__init__.py
index 3c8c095..77fd736 100644
--- a/src/pyrmv/raw/__init__.py
+++ b/src/pyrmv/raw/__init__.py
@@ -1,3 +1,7 @@
+import contextlib
+
+import requests
+
 from .board_arrival import board_arrival
 from .board_departure import board_departure
 from .him_search import him_search
@@ -6,3 +10,8 @@ from .stop_by_coords import stop_by_coords
 from .stop_by_name import stop_by_name
 from .trip_find import trip_find
 from .trip_recon import trip_recon
+
+with contextlib.suppress(ImportError):
+    import ujson
+
+    requests.models.complexjson = ujson
diff --git a/tox.ini b/tox.ini
index e4c6404..b3d08ff 100644
--- a/tox.ini
+++ b/tox.ini
@@ -18,6 +18,7 @@ passenv =
 deps = 
     -r{toxinidir}/requirements/_.txt
     -r{toxinidir}/requirements/dev.txt
+    -r{toxinidir}/requirements/speed.txt
 commands =
     pytest --basetemp={envtmpdir} --cov=pyrmv --cov-report term-missing