diff --git a/.github/workflows/build-serpyco-rs.yml b/.github/workflows/build-serpyco-rs.yml
new file mode 100644
index 000000000..48ec7ee41
--- /dev/null
+++ b/.github/workflows/build-serpyco-rs.yml
@@ -0,0 +1,144 @@
+# SPDX-FileCopyrightText: 2026 The RISE Project
+# SPDX-License-Identifier: MIT
+---
+# This workflow is based on: https://github.com/ermakov-oleg/serpyco-rs/blob/v1.22.0/.github/workflows/CI.yml
+name: Build serpyco-rs wheels (riscv64)
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'serpyco-rs version to build (git tag without leading v, e.g. 1.22.0)'
+        required: true
+        default: '1.22.0'
+  pull_request:
+    paths:
+      - '.github/workflows/build-serpyco-rs.yml'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ inputs.version || '1.22.0' }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read  # to fetch code (actions/checkout)
+
+env:
+  # `inputs.version` is empty on pull_request events; default to 1.22.0 there.
+  SERPYCO_RS_VERSION: ${{ inputs.version || '1.22.0' }}
+  MANYLINUX_RISCV64_IMAGE: quay.io/pypa/manylinux_2_39_riscv64
+
+jobs:
+  setup:
+    uses: $/.github/workflows/_setup.yml
+
+  python_sdist:
+    needs: [setup]
+    runs-on: ubuntu-latest
+    outputs:
+      sdist_artifact_name: ${{ steps.build_sdist.outputs.sdist_artifact_name }}
+      package_version: ${{ steps.build_sdist.outputs.package_version }}
+    steps:
+      - name: Checkout serpyco-rs v${{ env.SERPYCO_RS_VERSION }}
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
+        with:
+          repository: ermakov-oleg/serpyco-rs
+          ref: v${{ env.SERPYCO_RS_VERSION }}
+          persist-credentials: false
+
+      - name: Install Python
+        uses: astral-sh/setup-uv@20cfd1bf945f4377ade1205e4dbc17946fc9a30d  # v10.0.1
+        with:
+          python-version: '3.12'
+          activate-environment: true
+          enable-cache: false
+
+      - name: Build sdist
+        id: build_sdist
+        run: |
+          set -euo pipefail
+          rm -rf dist
+
+          uv pip install 'maturin>=1,<2' build
+          python -m build --sdist --outdir dist
+
+          sdist_name="$(ls dist)"
+          {
+            echo "sdist_artifact_name=${sdist_name}"
+            echo "package_version=$(echo "${sdist_name}" | sed -En 's/serpyco_rs-(.+)\.tar\.gz/\1/p')"
+          } >> "$GITHUB_OUTPUT"
+
+      - name: Upload sdist artifact
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7.0.1
+        with:
+          name: ${{ steps.build_sdist.outputs.sdist_artifact_name }}
+          path: dist/${{ steps.build_sdist.outputs.sdist_artifact_name }}
+          if-no-files-found: error
+
+  build_wheels:
+    needs: [setup, python_sdist]
+    name: Build serpyco-rs ${{ needs.python_sdist.outputs.package_version }} ${{ matrix.python }}-manylinux_riscv64
+    runs-on: ubuntu-24.04-riscv
+    timeout-minutes: 60
+    strategy:
+      fail-fast: false
+      matrix:
+        # serpyco-rs's pyo3 dependency carries no abi3 feature, so upstream ships
+        # cp3x-cp3x wheels per interpreter (not abi3) - every version needs its
+        # own build. Repo-standard riscv64 target set; upstream builds and tests
+        # cp314t too, so it's kept here (unlike build-rtoml.yml's cp314t drop).
+        python: ["cp312", "cp313", "cp314", "cp314t"]
+
+    steps:
+      - name: Fetch sdist artifact
+        id: fetch_sdist
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c  # v8.0.1
+        with:
+          name: ${{ needs.python_sdist.outputs.sdist_artifact_name }}
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@20cfd1bf945f4377ade1205e4dbc17946fc9a30d  # v10.0.1
+        with:
+          python-version: '3.12'
+          activate-environment: true
+          enable-cache: false
+
+      - name: Build and test wheel
+        env:
+          CIBW_ARCHS: riscv64
+          # Only manylinux: rustup.rs ships no riscv64 musl host toolchain, so
+          # musllinux can't build (same reason build-sqloxide.yml skips it).
+          CIBW_BUILD: ${{ matrix.python }}-manylinux_riscv64
+          CIBW_MANYLINUX_RISCV64_IMAGE: ${{ env.MANYLINUX_RISCV64_IMAGE }}
+          # serpyco-rs ships no [tool.cibuildwheel], so the Rust toolchain its
+          # maturin backend needs is installed in-container here and put on PATH.
+          CIBW_BEFORE_ALL_LINUX: >-
+            curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
+          CIBW_ENVIRONMENT_LINUX: 'PATH="$PATH:$HOME/.cargo/bin"'
+          # Mirrors upstream's own `test` job (just ci-test -> pytest tests/).
+          # Tests live inside the sdist dir we pass to cibuildwheel, so reference
+          # them via {package} (= /project/serpyco-rs), NOT {project} - see gotcha 5.
+          CIBW_TEST_REQUIRES: pytest attrs python-dateutil multidict
+          CIBW_TEST_COMMAND: pytest -q {package}/tests -v
+        run: |
+          set -euo pipefail
+          mkdir serpyco-rs
+          tar zxf "${{ steps.fetch_sdist.outputs.download-path }}/${{ needs.python_sdist.outputs.sdist_artifact_name }}" \
+            --strip-components=1 -C serpyco-rs
+          uv pip install --upgrade cibuildwheel
+          python -m cibuildwheel --output-dir wheelhouse ./serpyco-rs
+
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7.0.1
+        with:
+          name: serpyco-rs-${{ needs.python_sdist.outputs.package_version }}-${{ matrix.python }}-manylinux_riscv64
+          path: ./wheelhouse/*.whl
+          if-no-files-found: error
+
+  publish:
+    name: Publish serpyco-rs ${{ needs.python_sdist.outputs.package_version }}
+    needs: [setup, python_sdist, build_wheels]
+    permissions:
+      contents: write
+      pull-requests: write
+    uses: $/.github/workflows/_publish-wheel.yml
+    with:
+      artifact-pattern: serpyco-rs-${{ needs.python_sdist.outputs.package_version }}-*-manylinux_riscv64