[Docs] Convert Sphinx docs to Fern

.github/CODEOWNERS

@@ -6,6 +6,9 @@ benchmarks/        @rapidsai/rmm-cpp-codeowners
 #python code owners
 python/            @rapidsai/rmm-python-codeowners
 
+#docs code owners
+fern/              @rapidsai/rmm-cpp-codeowners @rapidsai/rmm-python-codeowners
+
 #cmake code owners
 **/CMakeLists.txt  @rapidsai/rmm-cmake-codeowners
 **/cmake/          @rapidsai/rmm-cmake-codeowners

.github/workflows/pr.yaml

@@ -136,6 +136,7 @@ jobs:
           - '!ci/test_wheel.sh'
           - '!ci/validate_wheel.sh'
           - '!docs/**'
+          - '!fern/**'
           - '!img/**'
           - '!python/**'
         test_python_conda:
@@ -165,6 +166,7 @@ jobs:
           - '!cpp/.clang-tidy'
           - '!cpp/doxygen/**'
           - '!docs/**'
+          - '!fern/**'
           - '!img/**'
         test_python_wheels:
           - '**'
@@ -197,6 +199,7 @@ jobs:
           - '!cpp/.clang-tidy'
           - '!cpp/doxygen/**'
           - '!docs/**'
+          - '!fern/**'
           - '!img/**'
   checks:
     permissions:

.gitignore

@@ -98,6 +98,8 @@ cpp/doxygen/html
 cpp/doxygen/latex
 cpp/doxygen/xml
 docs/_build
+fern/pages/api_reference
+fern/sphinx/build
 
 #Java
 target
@@ -134,6 +136,7 @@ celerybeat-schedule
 
 # dotenv
 .env
+.venv-docs/
 
 # virtualenv
 .venv

build.sh

@@ -19,11 +19,12 @@ ARGS=$*
 # script, and that this script resides in the repo dir!
 REPODIR=$(cd "$(dirname "$0")"; pwd)
 
-VALIDARGS="clean librmm rmm -v -g -n --ptds -h tests benchmarks"
-HELP="$0 [clean] [librmm] [rmm] [-v] [-g] [-n] [--ptds] [--cmake-args=\"<args>\"] [-h]
+VALIDARGS="clean librmm rmm docs -v -g -n --ptds -h tests benchmarks"
+HELP="$0 [clean] [librmm] [rmm] [docs] [-v] [-g] [-n] [--ptds] [--cmake-args=\"<args>\"] [-h]
    clean                       - remove all existing build artifacts and configuration (start over)
    librmm                      - build and install the librmm C++ code
    rmm                         - build and install the rmm Python package
+   docs                        - validate the Fern documentation
    benchmarks                  - build benchmarks
    tests                       - build tests
    -v                          - verbose build mode
@@ -183,3 +184,8 @@ if (( NUMARGS == 0 )) || hasArg rmm; then
         "${PYTHON_ARGS_FOR_INSTALL[@]}" \
         "${REPODIR}"/python/rmm
 fi
+
+# Validate Fern docs
+if hasArg docs; then
+    "${REPODIR}/fern/build_docs.sh" "${FERN_DOCS_MODE:-check}"
+fi

ci/build_docs.sh

@@ -4,49 +4,23 @@
 
 set -euo pipefail
 
-rapids-logger "Downloading artifacts from previous jobs"
-CPP_CHANNEL=$(rapids-download-conda-from-github cpp)
-PYTHON_CHANNEL=$(rapids-download-from-github "$(rapids-package-name "conda_python" rmm --stable --cuda "$RAPIDS_CUDA_VERSION")")
-
-rapids-logger "Create test conda environment"
+rapids-logger "Create docs conda environment"
 
 . /opt/conda/etc/profile.d/conda.sh
 
 rapids-logger "Configuring conda strict channel priority"
 conda config --set channel_priority strict
 
-RAPIDS_VERSION_MAJOR_MINOR="$(rapids-version-major-minor)"
-export RAPIDS_VERSION_MAJOR_MINOR
-
 rapids-dependency-file-generator \
   --output conda \
   --file-key docs \
   --matrix "cuda=${RAPIDS_CUDA_VERSION%.*};arch=$(arch);py=${RAPIDS_PY_VERSION}" \
-  --prepend-channel "${CPP_CHANNEL}" \
-  --prepend-channel "${PYTHON_CHANNEL}" \
   | tee env.yaml
 
 rapids-mamba-retry env create --yes -f env.yaml -n docs
 conda activate docs
 
 rapids-print-env
 
-RAPIDS_DOCS_DIR="$(mktemp -d)"
-export RAPIDS_DOCS_DIR
-
-
-rapids-logger "Build CPP docs"
-pushd cpp/doxygen
-doxygen Doxyfile
-mkdir -p "${RAPIDS_DOCS_DIR}/librmm/html"
-mv html/* "${RAPIDS_DOCS_DIR}/librmm/html"
-popd
-
-rapids-logger "Build Python docs"
-pushd docs
-make dirhtml
-mkdir -p "${RAPIDS_DOCS_DIR}/rmm/html"
-mv _build/dirhtml/* "${RAPIDS_DOCS_DIR}/rmm/html"
-popd
-
-RAPIDS_VERSION_NUMBER="${RAPIDS_VERSION_MAJOR_MINOR}" rapids-upload-docs
+rapids-logger "Validate Fern docs"
+fern/build_docs.sh "${FERN_DOCS_MODE:-check}"

conda/environments/all_cuda-129_arch-aarch64.yaml

@@ -20,11 +20,9 @@ dependencies:
 - gcovr>=5.0
 - graphviz
 - identify>=2.5.20
-- ipython
-- make
 - myst-parser
-- nbsphinx
 - ninja
+- nodejs>=18
 - numba-cuda>=0.22.1,<0.29.0
 - numba>=0.60.0,<0.65.0
 - numpy>=1.23,<3.0
@@ -39,8 +37,7 @@ dependencies:
 - rapids-logger==0.2.*,>=0.0.0a0
 - scikit-build-core>=0.11.0
 - sphinx
-- sphinx-copybutton
+- sphinx-markdown-builder
 - sphinx-markdown-tables
-- sphinxcontrib-jquery
 - sysroot_linux-aarch64==2.28
 name: all_cuda-129_arch-aarch64

conda/environments/all_cuda-129_arch-x86_64.yaml

@@ -20,11 +20,9 @@ dependencies:
 - gcovr>=5.0
 - graphviz
 - identify>=2.5.20
-- ipython
-- make
 - myst-parser
-- nbsphinx
 - ninja
+- nodejs>=18
 - numba-cuda>=0.22.1,<0.29.0
 - numba>=0.60.0,<0.65.0
 - numpy>=1.23,<3.0
@@ -39,8 +37,7 @@ dependencies:
 - rapids-logger==0.2.*,>=0.0.0a0
 - scikit-build-core>=0.11.0
 - sphinx
-- sphinx-copybutton
+- sphinx-markdown-builder
 - sphinx-markdown-tables
-- sphinxcontrib-jquery
 - sysroot_linux-64==2.28
 name: all_cuda-129_arch-x86_64

conda/environments/all_cuda-132_arch-aarch64.yaml

@@ -20,11 +20,9 @@ dependencies:
 - gcovr>=5.0
 - graphviz
 - identify>=2.5.20
-- ipython
-- make
 - myst-parser
-- nbsphinx
 - ninja
+- nodejs>=18
 - numba-cuda>=0.22.1,<0.29.0
 - numba>=0.60.0,<0.65.0
 - numpy>=1.23,<3.0
@@ -39,8 +37,7 @@ dependencies:
 - rapids-logger==0.2.*,>=0.0.0a0
 - scikit-build-core>=0.11.0
 - sphinx
-- sphinx-copybutton
+- sphinx-markdown-builder
 - sphinx-markdown-tables
-- sphinxcontrib-jquery
 - sysroot_linux-aarch64==2.28
 name: all_cuda-132_arch-aarch64

conda/environments/all_cuda-132_arch-x86_64.yaml

@@ -20,11 +20,9 @@ dependencies:
 - gcovr>=5.0
 - graphviz
 - identify>=2.5.20
-- ipython
-- make
 - myst-parser
-- nbsphinx
 - ninja
+- nodejs>=18
 - numba-cuda>=0.22.1,<0.29.0
 - numba>=0.60.0,<0.65.0
 - numpy>=1.23,<3.0
@@ -39,8 +37,7 @@ dependencies:
 - rapids-logger==0.2.*,>=0.0.0a0
 - scikit-build-core>=0.11.0
 - sphinx
-- sphinx-copybutton
+- sphinx-markdown-builder
 - sphinx-markdown-tables
-- sphinxcontrib-jquery
 - sysroot_linux-64==2.28
 name: all_cuda-132_arch-x86_64

dependencies.yaml

@@ -68,9 +68,9 @@ files:
     includes:
       - cuda_version
       - docs
-      - py_version
-      - depends_on_rmm
       - depends_on_librmm
+      - depends_on_rmm
+      - py_version
   py_cpp_build:
     output: pyproject
     pyproject_dir: python/librmm
@@ -336,18 +336,16 @@ dependencies:
           - breathe>=4.35.0
           - *doxygen
           - graphviz
-          - ipython
-          - make
           - myst-parser
-          - nbsphinx
-          - &numba numba>=0.60.0,<0.65.0
-          - &numba_cuda numba-cuda>=0.22.1,<0.29.0
+          - nodejs>=18
+          - numba>=0.60.0,<0.65.0
+          - numba-cuda>=0.22.1,<0.29.0
           - numpydoc
+          - packaging
           - pydata-sphinx-theme>=0.15.4
           - sphinx
-          - sphinx-copybutton
+          - sphinx-markdown-builder
           - sphinx-markdown-tables
-          - sphinxcontrib-jquery
   py_version:
     specific:
       - output_types: conda
@@ -395,6 +393,8 @@ dependencies:
     common:
       - output_types: [conda, requirements, pyproject]
         packages:
+          - &numba numba>=0.60.0,<0.65.0
+          - &numba_cuda numba-cuda>=0.22.1,<0.29.0
           - packaging
           - pytest
           - pytest-cov

fern/build_docs.sh

@@ -0,0 +1,105 @@
+#!/bin/bash
+# SPDX-FileCopyrightText: Copyright (c) 2026, NVIDIA CORPORATION.
+# SPDX-License-Identifier: Apache-2.0
+
+set -euo pipefail
+
+SCRIPT_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+REPO_DIR=$(cd "${SCRIPT_DIR}/.." && pwd)
+MODE="${1:-check}"
+
+if [[ $# -gt 0 ]]; then
+  shift
+fi
+
+usage() {
+  cat <<'EOF'
+Usage: fern/build_docs.sh [check|preview|publish|dev] [fern arguments...]
+
+Modes:
+  check     Validate Fern configuration, links, and Markdown syntax.
+  preview   Build and publish a Fern preview deployment.
+  publish   Build and publish the production Fern docs site.
+  dev       Start Fern's local docs preview server.
+EOF
+}
+
+require_node_18() {
+  if ! command -v node >/dev/null 2>&1; then
+    echo "Fern docs require Node.js 18 or newer, but node was not found on PATH." >&2
+    exit 1
+  fi
+
+  local node_version
+  local node_major
+  node_version=$(node -p 'process.versions.node' 2>/dev/null || true)
+  node_major="${node_version%%.*}"
+
+  if [[ ! "${node_major}" =~ ^[0-9]+$ || "${node_major}" -lt 18 ]]; then
+    echo "Fern docs require Node.js 18 or newer, but found Node.js ${node_version:-unknown}." >&2
+    exit 1
+  fi
+}
+
+require_node_18
+
+if [[ -n "${FERN_CLI:-}" ]]; then
+  FERN_CMD=("${FERN_CLI}")
+elif command -v fern >/dev/null 2>&1; then
+  FERN_CMD=("fern")
+else
+  FERN_CMD=("npx" "--yes" "fern-api@5.30.4")
+fi
+
+run_fern() {
+  "${FERN_CMD[@]}" "$@"
+}
+
+generate_api_reference() {
+  pushd "${REPO_DIR}" >/dev/null
+  python3 fern/scripts/generate_api_reference.py
+  popd >/dev/null
+}
+
+run_checks() {
+  pushd "${REPO_DIR}" >/dev/null
+  run_fern check --warnings
+  run_fern docs md check
+  popd >/dev/null
+}
+
+case "${MODE}" in
+  check)
+    generate_api_reference
+    run_checks
+    ;;
+  preview)
+    generate_api_reference
+    run_checks
+    pushd "${REPO_DIR}" >/dev/null
+    run_fern generate --docs --preview "$@"
+    popd >/dev/null
+    ;;
+  publish)
+    generate_api_reference
+    run_checks
+    pushd "${REPO_DIR}" >/dev/null
+    run_fern generate --docs "$@"
+    popd >/dev/null
+    ;;
+  dev)
+    generate_api_reference
+    pushd "${REPO_DIR}" >/dev/null
+    run_fern docs dev "$@"
+    popd >/dev/null
+    ;;
+  -h|--help|help)
+    usage
+    ;;
+  *)
+    echo "Unknown mode: ${MODE}" >&2
+    echo >&2
+    usage >&2
+    exit 2
+    ;;
+esac