diff --git a/.github/workflows/utils.yml b/.github/workflows/utils.yml
index 0ef782e..0b90055 100644
--- a/.github/workflows/utils.yml
+++ b/.github/workflows/utils.yml
@@ -27,31 +27,6 @@ jobs:
       uses: actions/checkout@v4
       with:
         submodules: recursive
-    - name: Initialise docker cache
-      uses: jpribyl/action-docker-layer-caching@v0.1.1
-      continue-on-error: true
-    # Building in stages to keep the logs navigable
-    - name: Build Container (Base)
-      working-directory: utils
-      run: docker build --build-arg USER_ID="$(id -u)" --build-arg GROUP_ID="$(id -g)" -t rosettaboy-base --target base-builder .
-    - name: Build Container (Go)
-      working-directory: utils
-      run: docker build --build-arg USER_ID="$(id -u)" --build-arg GROUP_ID="$(id -g)" -t rosettaboy-go --target go-builder .
-    - name: Build Container (Nim)
-      working-directory: utils
-      run: docker build --build-arg USER_ID="$(id -u)" --build-arg GROUP_ID="$(id -g)" -t rosettaboy-nim --target nim-builder .
-    - name: Build Container (PHP)
-      working-directory: utils
-      run: docker build --build-arg USER_ID="$(id -u)" --build-arg GROUP_ID="$(id -g)" -t rosettaboy-php --target php-builder .
-    - name: Build Container (Python)
-      working-directory: utils
-      run: docker build --build-arg USER_ID="$(id -u)" --build-arg GROUP_ID="$(id -g)" -t rosettaboy-py --target py-builder .
-    - name: Build Container (Rust)
-      working-directory: utils
-      run: docker build --build-arg USER_ID="$(id -u)" --build-arg GROUP_ID="$(id -g)" -t rosettaboy-rs --target rs-builder .
-    - name: Build Container (Zig)
-      working-directory: utils
-      run: docker build --build-arg USER_ID="$(id -u)" --build-arg GROUP_ID="$(id -g)" -t rosettaboy-zig --target zig-builder .
     - name: Build Container
       working-directory: utils
       run: docker build --build-arg USER_ID="$(id -u)" --build-arg GROUP_ID="$(id -g)" -t rosettaboy .
diff --git a/utils/Dockerfile b/utils/Dockerfile
index 2864c3a..37d5760 100644
--- a/utils/Dockerfile
+++ b/utils/Dockerfile
@@ -1,130 +1,8 @@
-ARG GO_VERSION=1.22.2
-ARG NIM_VERSION=2.0.2
-ARG PHP_VERSION=8.3.4
-# 3.12.2
-ARG PYTHON_VERSION=3.11.5
-ARG RUST_VERSION=1.77.1
-ARG ZIG_VERSION=0.11.0
-
-
-#######################################################################
-# Foundations
-
-FROM debian:unstable AS base-pkgs
-# Install foundations-which-rarely-change up-front so we can cache
-# them, and then install language-specific things on top
+FROM debian:unstable AS final
 USER root
 RUN apt update && apt install -y \
     build-essential linux-perf valgrind vim git mercurial libsdl2-dev wget curl sudo
 
-FROM base-pkgs AS base-builder
-# build in /home/dev using a static user ID so that we don't
-# need to rebuild the world when USER_ID / GROUP_ID changes,
-# then copy to /home/dev using a dynamic user ID later
-RUN adduser --disabled-password dev
-
-
-#######################################################################
-# Go
-
-FROM base-builder AS go-builder
-ARG GO_VERSION
-USER dev
-RUN mkdir /home/dev/.go \
-    && wget -nv https://go.dev/dl/go${GO_VERSION}.linux-$(dpkg --print-architecture).tar.gz -O - \
-    | tar --strip-components=1 -xz -C /home/dev/.go
-ENV PATH="/home/dev/.go/bin:$PATH"
-
-
-#######################################################################
-# Nim
-
-FROM base-builder AS nim-builder
-ARG NIM_VERSION
-USER dev
-ENV PATH="/home/dev/.nim/bin:$PATH"
-# choosenim doesn't work on arm64 D:
-#ENV CHOOSENIM_CHOOSE_VERSION=${NIM_VERSION}
-#RUN curl https://nim-lang.org/choosenim/init.sh -sSf | sh -s -- -y && \
-#    nimble refresh
-RUN wget -nv https://nim-lang.org/download/nim-${NIM_VERSION}.tar.xz -O - \
-    | tar -xJ -C /tmp
-RUN cd /tmp/nim-${NIM_VERSION} \
-    && ./build.sh \
-    && bin/nim c koch \
-    && ./koch boot -d:release \
-    && ./koch tools \
-    && ./install.sh /tmp/install-nim \
-    && mv /tmp/install-nim/nim /home/dev/.nim \
-    && cp ./bin/nimble /home/dev/.nim/bin/ \
-    && nimble refresh
-
-#######################################################################
-# PHP
-
-FROM base-builder AS php-builder
-ARG PHP_VERSION
-RUN apt-get install -y libxml2-dev libsqlite3-dev libssl-dev autoconf
-USER dev
-RUN wget -nv https://www.php.net/distributions/php-${PHP_VERSION}.tar.gz -O - \
-    | tar -xz -C /tmp
-RUN cd /tmp/php-${PHP_VERSION} && ./configure --prefix=/home/dev/.php --with-openssl && make -j install
-ENV PATH="/home/dev/.php/bin:$PATH"
-RUN curl https://getcomposer.org/installer | php -- --quiet --install-dir=/home/dev/.php/bin/ --filename=composer
-RUN git clone https://github.com/Ponup/php-sdl ~/php-sdl \
-    && cd ~/php-sdl && phpize && ./configure && make -j
-
-
-#######################################################################
-# Python
-
-FROM base-builder AS py-builder
-ARG PYTHON_VERSION
-USER root
-RUN apt-get install -y --no-install-recommends \
-    make build-essential libssl-dev zlib1g-dev libbz2-dev libreadline-dev \
-    libsqlite3-dev wget curl llvm libncurses5-dev xz-utils tk-dev \
-    libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev \
-    && apt-get install -y mecab-ipadic-utf8
-USER dev
-ENV PYENV_ROOT="/home/dev/.pyenv"
-ENV PATH="/home/dev/.pyenv/shims:/home/dev/.pyenv/bin:$PATH"
-RUN git clone --depth=1 https://github.com/yyuu/pyenv /home/dev/.pyenv \
-    && pyenv install ${PYTHON_VERSION} \
-	&& pyenv global ${PYTHON_VERSION} \
-	&& pyenv rehash
-
-
-#######################################################################
-# Rust
-
-FROM base-builder AS rs-builder
-ARG RUST_VERSION
-USER dev
-ENV PATH="/home/dev/.cargo/bin:$PATH"
-RUN wget -nv -qO - https://sh.rustup.rs | sh -s -- --default-toolchain ${RUST_VERSION} -y \
-    && cargo search foo
-# Cranelift is only in nightly
-RUN rustup toolchain install nightly \
-    && rustup component add rustc-codegen-cranelift-preview --toolchain nightly
-
-
-#######################################################################
-# Zig
-
-FROM base-builder AS zig-builder
-ARG ZIG_VERSION
-USER dev
-RUN mkdir /home/dev/.zig \
-    && wget -nv https://ziglang.org/builds/zig-linux-$(uname -m)-${ZIG_VERSION}.tar.xz -O - \
-    | tar --strip-components=1 -C ~/.zig -xJ
-
-
-#######################################################################
-# Final image
-
-FROM base-pkgs AS final
-
 # Configure developer environment
 ARG USER_ID=1000
 ARG GROUP_ID=$USER_ID
@@ -139,29 +17,29 @@ USER root
 RUN apt update && apt install -y cmake clang clang-format-14 libfmt-dev
 
 # Install Go tools
-COPY --from=go-builder --chown=${USER_ID}:${GROUP_ID} /home/dev/.go /home/dev/.go
+COPY --from=shish2k/rosettaboy-devkit-go:1.22.2 --chown=${USER_ID}:${GROUP_ID} /home/dev/.go /home/dev/.go
 ENV PATH="/home/dev/.go/bin:$PATH"
 
 # Install Nim tools
-COPY --from=nim-builder --chown=${USER_ID}:${GROUP_ID} /home/dev/.nim /home/dev/.nim
+COPY --from=shish2k/rosettaboy-devkit-nim:2.0.2 --chown=${USER_ID}:${GROUP_ID} /home/dev/.nim /home/dev/.nim
 ENV PATH="/home/dev/.nim/bin:$PATH"
 
 # Install PHP tools
-COPY --from=php-builder --chown=${USER_ID}:${GROUP_ID} /home/dev/.php /home/dev/.php
+COPY --from=shish2k/rosettaboy-devkit-php:8.3.4 --chown=${USER_ID}:${GROUP_ID} /home/dev/.php /home/dev/.php
 ENV PATH="/home/dev/.php/bin:$PATH"
 
 # Install Python tools
-COPY --from=py-builder --chown=${USER_ID}:${GROUP_ID} /home/dev/.pyenv /home/dev/.pyenv
+COPY --from=shish2k/rosettaboy-devkit-python:3.11.5 --chown=${USER_ID}:${GROUP_ID} /home/dev/.pyenv /home/dev/.pyenv
 ENV PYENV_ROOT="/home/dev/.pyenv"
 ENV PATH="/home/dev/.pyenv/shims:/home/dev/.pyenv/bin:$PATH"
 
 # Install Rust tools
-COPY --from=rs-builder --chown=${USER_ID}:${GROUP_ID} /home/dev/.rustup /home/dev/.rustup
-COPY --from=rs-builder --chown=${USER_ID}:${GROUP_ID} /home/dev/.cargo /home/dev/.cargo
+COPY --from=shish2k/rosettaboy-devkit-rust:1.77.1 --chown=${USER_ID}:${GROUP_ID} /home/dev/.rustup /home/dev/.rustup
+COPY --from=shish2k/rosettaboy-devkit-rust:1.77.1 --chown=${USER_ID}:${GROUP_ID} /home/dev/.cargo /home/dev/.cargo
 ENV PATH="/home/dev/.cargo/bin:$PATH"
 
 # Install Zig tools
-COPY --from=zig-builder --chown=${USER_ID}:${GROUP_ID} /home/dev/.zig /home/dev/.zig
+COPY --from=shish2k/rosettaboy-devkit-zig:0.11.0 --chown=${USER_ID}:${GROUP_ID} /home/dev/.zig /home/dev/.zig
 ENV PATH="/home/dev/.zig:$PATH"
 
 # Get ready to go