diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 6dcaece..8a89691 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -1,3 +1,7 @@
+# Release workflow: git tag v* builds sequencer tarballs, CM images, and pushes
+# watchdog OCI images to ghcr.io + docker.io (requires DOCKERHUB_USERNAME /
+# DOCKERHUB_TOKEN repo secrets, same as cartesi/cli).
+
 name: Release
 
 on:
@@ -18,6 +22,7 @@ on:
 
 permissions:
   contents: write
+  packages: write
 
 jobs:
   build-sequencer:
@@ -161,23 +166,8 @@ jobs:
           path: dist/canonical-machine-image-*.tar.gz
 
   build-watchdog-image:
-    name: Build watchdog image (${{ matrix.arch }})
-    # arm64 must build on an arm64 host — docker build --platform linux/arm64 on
-    # ubuntu-latest (amd64) without QEMU hits "exec format error" in RUN steps.
-    runs-on: ${{ matrix.runs_on }}
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - arch: amd64
-            platform: linux/amd64
-            runs_on: ubuntu-latest
-            deb_sha_env: CARTESI_MACHINE_SHA256_AMD64
-          - arch: arm64
-            platform: linux/arm64
-            runs_on: ubuntu-24.04-arm
-            deb_sha_env: CARTESI_MACHINE_SHA256_ARM64
-
+    name: Build and push watchdog image
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout
         uses: actions/checkout@v5
@@ -185,34 +175,43 @@ jobs:
       - name: Load toolchain pins
         uses: ./.github/actions/load-toolchain-pins
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v4
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v4
 
-      - name: Build and export watchdog image
-        env:
-          TAG: ${{ inputs.tag || github.ref_name }}
-          DEB_SHA_ENV: ${{ matrix.deb_sha_env }}
-        run: |
-          set -euo pipefail
-          DEB_SHA="${!DEB_SHA_ENV}"
-          image="sequencer-watchdog:${TAG}"
-          docker build \
-            --platform "${{ matrix.platform }}" \
-            --build-arg "RELEASE_TAG=${TAG}" \
-            --build-arg "GIT_COMMIT=${GITHUB_SHA}" \
-            --build-arg "CARTESI_MACHINE_VERSION=${CARTESI_MACHINE_VERSION}" \
-            --build-arg "CARTESI_MACHINE_DEB_SHA256=${DEB_SHA}" \
-            -f watchdog/Dockerfile \
-            -t "${image}" \
-            .
-          mkdir -p dist
-          docker save "${image}" | gzip -9 > "dist/sequencer-watchdog-${TAG}-linux-${{ matrix.arch }}.tar.gz"
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Upload artifact
-        uses: actions/upload-artifact@v6
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Build and push watchdog image
+        uses: docker/build-push-action@v6
         with:
-          name: watchdog-image-linux-${{ matrix.arch }}
-          path: dist/sequencer-watchdog-*.tar.gz
+          context: .
+          file: watchdog/Dockerfile
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: |
+            ghcr.io/cartesi/sequencer-watchdog:${{ inputs.tag || github.ref_name }}
+            docker.io/cartesi/sequencer-watchdog:${{ inputs.tag || github.ref_name }}
+          build-args: |
+            RELEASE_TAG=${{ inputs.tag || github.ref_name }}
+            GIT_COMMIT=${{ github.sha }}
+            CARTESI_MACHINE_VERSION=${{ env.CARTESI_MACHINE_VERSION }}
+            CARTESI_MACHINE_DEB_SHA256_AMD64=${{ env.CARTESI_MACHINE_SHA256_AMD64 }}
+            CARTESI_MACHINE_DEB_SHA256_ARM64=${{ env.CARTESI_MACHINE_SHA256_ARM64 }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
 
   publish:
     name: Publish GitHub Release
diff --git a/docs/watchdog/operator-deployment.md b/docs/watchdog/operator-deployment.md
index 6116eed..59ed1bb 100644
--- a/docs/watchdog/operator-deployment.md
+++ b/docs/watchdog/operator-deployment.md
@@ -46,12 +46,21 @@ curl -sS -o /dev/null -w "%{http_code}\n" "$WATCHDOG_SEQUENCER_URL/finalized_sta
 # expect 200 when a finalized snapshot exists (404 = not promoted yet or wrong host)
 ```
 
-### 2. Watchdog runtime (release bundle or local build)
+### 2. Watchdog runtime (release image or local build)
 
-**Production (recommended):** use the **release bundle** for tag `vX` — same
+**Production (recommended):** pull the **release container image** for tag `vX` — same
 git tag as the sequencer binary and `canonical-machine-image-*-vX.tar.gz`.
-Load `sequencer-watchdog-vX-linux-<arch>.tar.gz` (`docker load`) and verify
-alignment via `release-manifest-vX.json` and `/opt/watchdog/RELEASE.json`
+
+**Container images (preferred for Dockerfile / Fly.io assembly):**
+
+| Registry | Image |
+|----------|-------|
+| GHCR | `ghcr.io/cartesi/sequencer-watchdog:vX` |
+| Docker Hub | `docker.io/cartesi/sequencer-watchdog:vX` |
+
+Multi-arch manifest (`amd64` + `arm64`).
+
+Verify alignment via `release-manifest-vX.json` and `/opt/watchdog/RELEASE.json`
 inside the image. Toolchain pins live in [`toolchain-pins.env`](../../toolchain-pins.env).
 
 `cartesi-machine` in the watchdog image **must** match
@@ -59,10 +68,38 @@ inside the image. Toolchain pins live in [`toolchain-pins.env`](../../toolchain-
 (the emulator that built the CM image tarball). Mismatch causes load failures
 or false `state_mismatch`.
 
-Release image quick run:
+**Compose a custom image (e.g. Fly.io rootfs)** — base on `debian:trixie-slim`,
+install the same runtime packages as the release image, then copy from the
+published watchdog image:
+
+```dockerfile
+FROM debian:trixie-slim
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    lua5.4 libcurl4 libslirp0 libgomp1 ca-certificates util-linux \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY --from=ghcr.io/cartesi/sequencer-watchdog:vX /opt/watchdog /opt/watchdog
+COPY --from=ghcr.io/cartesi/sequencer-watchdog:vX /usr/local/bin/sequencer-watchdog /usr/local/bin/sequencer-watchdog
+COPY --from=ghcr.io/cartesi/sequencer-watchdog:vX /usr/local/bin/cartesi-machine /usr/local/bin/cartesi-machine
+COPY --from=ghcr.io/cartesi/sequencer-watchdog:vX /usr/local/lib/ /usr/local/lib/
+COPY --from=ghcr.io/cartesi/sequencer-watchdog:vX /usr/local/lib/lua/ /usr/local/lib/lua/
+COPY --from=ghcr.io/cartesi/sequencer-watchdog:vX /usr/local/share/lua/ /usr/local/share/lua/
+COPY --from=ghcr.io/cartesi/sequencer-watchdog:vX /usr/local/share/cartesi-machine/ /usr/local/share/cartesi-machine/
+
+ENV WATCHDOG_LUA_DEPS=/opt/watchdog/lib \
+    LUA_PATH="/opt/watchdog/lua/?.lua;/opt/watchdog/lua/?/init.lua;/usr/local/share/lua/5.4/?.lua;/usr/local/share/lua/5.4/?/init.lua;;" \
+    LUA_CPATH="/opt/watchdog/lib/?.so;/usr/local/lib/lua/5.4/?.so;;" \
+    LD_LIBRARY_PATH="/usr/local/lib" \
+    PATH="/usr/local/share/cartesi-machine:${PATH}"
+
+ENTRYPOINT ["/usr/local/bin/sequencer-watchdog"]
+```
+
+**Run from the published image:**
 
 ```bash
-docker load < sequencer-watchdog-vX-linux-amd64.tar.gz
+docker pull ghcr.io/cartesi/sequencer-watchdog:vX
 
 docker run --rm \
   -e WATCHDOG_SEQUENCER_URL="https://<internal-sequencer>" \
@@ -73,13 +110,13 @@ docker run --rm \
   -e WATCHDOG_CM_SNAPSHOT_SAFE_BLOCK="<bootstrap inclusion_block>" \
   -v /var/lib/watchdog/state:/watchdog-state \
   -v /var/lib/watchdog/cm-bootstrap:/cm-bootstrap:ro \
-  sequencer-watchdog:vX init
+  ghcr.io/cartesi/sequencer-watchdog:vX init
 
 docker run --rm \
   -e WATCHDOG_L1_RPC_URL="https://<archive-rpc>" \
   -e WATCHDOG_STATE_DIR=/watchdog-state \
   -v /var/lib/watchdog/state:/watchdog-state \
-  sequencer-watchdog:vX tick
+  ghcr.io/cartesi/sequencer-watchdog:vX tick
 ```
 
 **Local / dev build:**
diff --git a/scripts/ci-watchdog-docker-smoke.sh b/scripts/ci-watchdog-docker-smoke.sh
index 49ddacf..a1ff03c 100755
--- a/scripts/ci-watchdog-docker-smoke.sh
+++ b/scripts/ci-watchdog-docker-smoke.sh
@@ -9,32 +9,13 @@ cd "${root}"
 source toolchain-pins.env
 
 image="sequencer-watchdog:ci-smoke"
-if command -v dpkg >/dev/null 2>&1; then
-  arch="$(dpkg --print-architecture)"
-else
-  case "$(uname -m)" in
-    x86_64) arch=amd64 ;;
-    aarch64 | arm64) arch=arm64 ;;
-    *)
-      echo "unsupported arch for watchdog docker smoke: $(uname -m)" >&2
-      exit 1
-      ;;
-  esac
-fi
-case "${arch}" in
-  amd64) deb_sha="${CARTESI_MACHINE_SHA256_AMD64}" ;;
-  arm64) deb_sha="${CARTESI_MACHINE_SHA256_ARM64}" ;;
-  *)
-    echo "unsupported arch for watchdog docker smoke: ${arch}" >&2
-    exit 1
-    ;;
-esac
 
 docker build \
   --build-arg "RELEASE_TAG=ci-smoke" \
   --build-arg "GIT_COMMIT=local" \
   --build-arg "CARTESI_MACHINE_VERSION=${CARTESI_MACHINE_VERSION}" \
-  --build-arg "CARTESI_MACHINE_DEB_SHA256=${deb_sha}" \
+  --build-arg "CARTESI_MACHINE_DEB_SHA256_AMD64=${CARTESI_MACHINE_SHA256_AMD64}" \
+  --build-arg "CARTESI_MACHINE_DEB_SHA256_ARM64=${CARTESI_MACHINE_SHA256_ARM64}" \
   -f watchdog/Dockerfile \
   -t "${image}" \
   .
diff --git a/scripts/generate-release-manifest.sh b/scripts/generate-release-manifest.sh
index 5bfb75f..5073d74 100755
--- a/scripts/generate-release-manifest.sh
+++ b/scripts/generate-release-manifest.sh
@@ -58,8 +58,8 @@ artifacts_json="$(cat <<EOF
   {"name":"sequencer-${tag}-linux-arm64.tar.gz","kind":"sequencer","arch":"arm64"},
   {"name":"canonical-machine-image-devnet-${tag}.tar.gz","kind":"cm_image","chain":"devnet"},
   {"name":"canonical-machine-image-sepolia-${tag}.tar.gz","kind":"cm_image","chain":"sepolia"},
-  {"name":"sequencer-watchdog-${tag}-linux-amd64.tar.gz","kind":"watchdog_image","arch":"amd64","format":"docker-save"},
-  {"name":"sequencer-watchdog-${tag}-linux-arm64.tar.gz","kind":"watchdog_image","arch":"arm64","format":"docker-save"}
+  {"name":"ghcr.io/cartesi/sequencer-watchdog:${tag}","kind":"watchdog_image","format":"oci","arch":"multi","registry":"ghcr"},
+  {"name":"docker.io/cartesi/sequencer-watchdog:${tag}","kind":"watchdog_image","format":"oci","arch":"multi","registry":"dockerhub"}
 ]
 EOF
 )"
diff --git a/watchdog/Dockerfile b/watchdog/Dockerfile
index 85b847e..e697982 100644
--- a/watchdog/Dockerfile
+++ b/watchdog/Dockerfile
@@ -9,7 +9,8 @@ FROM debian:${DEBIAN_VERSION} AS build
 SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 
 ARG CARTESI_MACHINE_VERSION
-ARG CARTESI_MACHINE_DEB_SHA256
+ARG CARTESI_MACHINE_DEB_SHA256_AMD64
+ARG CARTESI_MACHINE_DEB_SHA256_ARM64
 ARG TARGETARCH
 
 # wget + ca-certificates fetch the cartesi-machine .deb; gcc/pkg-config + Lua
@@ -33,13 +34,13 @@ COPY watchdog/third_party watchdog/third_party
 RUN bash scripts/watchdog-lua-deps.sh
 
 RUN case "${TARGETARCH}" in \
-      amd64) CM_ARCH=amd64 ;; \
-      arm64) CM_ARCH=arm64 ;; \
+      amd64) DEB_SHA="${CARTESI_MACHINE_DEB_SHA256_AMD64}"; CM_ARCH=amd64 ;; \
+      arm64) DEB_SHA="${CARTESI_MACHINE_DEB_SHA256_ARM64}"; CM_ARCH=arm64 ;; \
       *) echo "unsupported TARGETARCH=${TARGETARCH}" >&2; exit 1 ;; \
     esac \
     && wget -O /tmp/machine-emulator.deb \
       "https://github.com/cartesi/machine-emulator/releases/download/${CARTESI_MACHINE_VERSION}/machine-emulator_${CM_ARCH}.deb" \
-    && echo "${CARTESI_MACHINE_DEB_SHA256}  /tmp/machine-emulator.deb" | sha256sum --check \
+    && echo "${DEB_SHA}  /tmp/machine-emulator.deb" | sha256sum --check \
     && dpkg-deb -x /tmp/machine-emulator.deb /tmp/cm \
     && mkdir -p /out/bin /out/lib /out/lib/lua/5.4 /out/share/cartesi-machine /out/share/lua/5.4 \
     && cp -a /tmp/cm/usr/bin/cartesi-machine /out/bin/ \