diff --git a/json11/build.sh b/json11/build.sh
new file mode 100755
index 0000000..acdf6f4
--- /dev/null
+++ b/json11/build.sh
@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null && pwd)"
+cd "$DIR"
+
+VERSION="db00e9369a92aa74bf630a2ffb092a4b0b132c01"
+INSTALL_DIR="$DIR/json11/install"
+VERSION_FILE="$INSTALL_DIR/VERSION"
+
+# Idempotent: skip if already built at this source revision.
+if [ -f "$INSTALL_DIR/lib/libjson11.a" ] && [ -f "$INSTALL_DIR/include/json11/json11.hpp" ] && \
+  [ -f "$VERSION_FILE" ] && [ "$(cat "$VERSION_FILE")" = "$VERSION" ]; then
+  echo "json11 already present, skipping build."
+  exit 0
+fi
+
+if [ ! -d "$DIR/json11-src/.git" ]; then
+  git clone https://github.com/dropbox/json11.git json11-src
+fi
+
+git -C json11-src fetch --force origin
+git -C json11-src checkout --force "$VERSION"
+
+BUILD_DIR="$DIR/build"
+rm -rf "$BUILD_DIR" "$INSTALL_DIR"
+mkdir -p "$BUILD_DIR" "$INSTALL_DIR/lib" "$INSTALL_DIR/include/json11"
+
+CXX="${CXX:-c++}"
+AR="${AR:-ar}"
+
+"$CXX" -std=c++11 -fPIC -O2 -c "$DIR/json11-src/json11.cpp" -o "$BUILD_DIR/json11.o"
+"$AR" rcs "$INSTALL_DIR/lib/libjson11.a" "$BUILD_DIR/json11.o"
+cp "$DIR/json11-src/json11.hpp" "$INSTALL_DIR/include/json11/json11.hpp"
+echo "$VERSION" > "$VERSION_FILE"
+
+# Keep workspace small and deterministic across builds.
+rm -rf "$DIR/json11-src" "$BUILD_DIR"
+
+echo "Installed json11 to $INSTALL_DIR"
+du -sh "$INSTALL_DIR"
diff --git a/json11/json11/__init__.py b/json11/json11/__init__.py
new file mode 100644
index 0000000..4994080
--- /dev/null
+++ b/json11/json11/__init__.py
@@ -0,0 +1,10 @@
+import os
+
+DIR = os.path.join(os.path.dirname(__file__), "install")
+LIB_DIR = os.path.join(DIR, "lib")
+INCLUDE_DIR = os.path.join(DIR, "include")
+
+
+def smoketest():
+  assert os.path.isfile(os.path.join(LIB_DIR, "libjson11.a")), "libjson11.a not found"
+  assert os.path.isfile(os.path.join(INCLUDE_DIR, "json11", "json11.hpp")), "json11/json11.hpp not found"
diff --git a/json11/pyproject.toml b/json11/pyproject.toml
new file mode 100644
index 0000000..ecf0377
--- /dev/null
+++ b/json11/pyproject.toml
@@ -0,0 +1,15 @@
+[build-system]
+requires = ["setuptools>=64", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "json11"
+version = "20170411.0"
+description = "json11 JSON parser library (static build)"
+requires-python = ">=3.8"
+
+[tool.setuptools.packages.find]
+include = ["json11*"]
+
+[tool.setuptools.package-data]
+json11 = ["install/**/*"]
diff --git a/json11/setup.py b/json11/setup.py
new file mode 100644
index 0000000..6a6efda
--- /dev/null
+++ b/json11/setup.py
@@ -0,0 +1,61 @@
+import os
+import platform
+import subprocess
+
+from setuptools.command.build_py import build_py
+
+try:
+  from wheel.bdist_wheel import bdist_wheel
+except ImportError:
+  bdist_wheel = None
+
+
+class BuildJson11(build_py):
+  """Run build.sh to compile json11 before collecting package data."""
+
+  def run(self):
+    pkg_dir = os.path.dirname(os.path.abspath(__file__))
+    marker = os.path.join(pkg_dir, "json11", "install", "lib", "libjson11.a")
+
+    if not os.path.exists(marker):
+      build_script = os.path.join(pkg_dir, "build.sh")
+      subprocess.check_call(["bash", build_script], cwd=pkg_dir)
+
+    super().run()
+
+
+cmdclass = {"build_py": BuildJson11}
+
+if bdist_wheel is not None:
+
+  class PlatformWheel(bdist_wheel):
+    """Produce a platform-specific, Python-version-agnostic wheel."""
+
+    def finalize_options(self):
+      super().finalize_options()
+      self.root_is_pure = False
+
+    def get_tag(self):
+      system = platform.system()
+      machine = platform.machine()
+
+      if system == "Linux":
+        plat = f"linux_{machine}"
+      elif system == "Darwin":
+        plat = "macosx_11_0_arm64"
+      else:
+        plat = f"{system.lower()}_{machine}"
+
+      return "py3", "none", plat
+
+  cmdclass["bdist_wheel"] = PlatformWheel
+
+
+def setup():
+  from setuptools import setup as _setup
+
+  _setup(cmdclass=cmdclass)
+
+
+if __name__ == "__main__":
+  setup()
diff --git a/pyproject.toml b/pyproject.toml
index c72ed28..5188379 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,6 +7,7 @@ members = [
   "ffmpeg",
   "gcc-arm-none-eabi",
   "git-lfs",
+  "json11",
   "libjpeg",
   "libyuv",
   "ncurses",