diff --git a/MANIFEST.in b/MANIFEST.in
index d9c32908b0..d079cf5bf8 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,5 +1,3 @@
 include LICENSE.txt
 include README.md
-include requires-install.txt
-include requires-express.txt
 include plotly/package_data/widgetbundle.js
diff --git a/pyproject.toml b/pyproject.toml
index 699e20ceb1..e4afcdb57d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,9 +38,14 @@ classifiers = [
 requires-python = ">=3.8"
 license = {file="LICENSE.txt"}
 version = "6.0.0"
-dynamic = ["dependencies"]
+dependencies = [
+    "narwhals>=1.15.1",
+    "packaging"
+]
+
+[project.optional-dependencies]
+express = ["numpy"]
 
-# TODO: check that this works
 [tool.setuptools.packages.find]
 where = ["."]
 include = ["plotly*", "_plotly*"]
diff --git a/requires-express.txt b/requires-express.txt
deleted file mode 100644
index f561197347..0000000000
--- a/requires-express.txt
+++ /dev/null
@@ -1,8 +0,0 @@
-### Required dependencies for Plotly Express    ###
-###                                             ###
-### To install, run:                            ###
-###      $ pip install -r requires-express.txt  ###
-###                                             ###
-###################################################
-
-numpy
diff --git a/requires-install.txt b/requires-install.txt
deleted file mode 100644
index 2923ec9d8a..0000000000
--- a/requires-install.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-### Dependencies for Core Plotly Functionality  ###
-###                                             ###
-### To install, run:                            ###
-###      $ pip install -r requires-install.txt  ###
-###                                             ###
-###################################################
-
-## dataframe agnostic layer ##
-narwhals>=1.15.1
-packaging