diff --git a/devel/build b/devel/build
index 72e7d121..17a59b46 100755
--- a/devel/build
+++ b/devel/build
@@ -53,20 +53,36 @@ if ! docker buildx inspect "$builder" &>/dev/null; then
     docker buildx create --name "$builder" --driver docker-container --driver-opt network=host
 fi
 
-BUILDER_IMAGE=nextstrain/base-builder
+BUILD_PLATFORM_BUILDER_IMAGE=nextstrain/base-builder-build-platform
+TARGET_PLATFORM_BUILDER_IMAGE=nextstrain/base-builder-target-platform
 FINAL_IMAGE=nextstrain/base
 
 docker buildx build \
-    --target builder \
+    --target builder-build-platform \
     --builder "$builder" \
     --platform "$platform" \
     --build-arg CACHE_DATE \
-    --cache-from "$BUILDER_IMAGE:latest" \
-    --cache-from "$BUILDER_IMAGE:$tag" \
-    --cache-from "$registry/$BUILDER_IMAGE:latest" \
-    --cache-from "$registry/$BUILDER_IMAGE:$tag" \
+    --cache-from "$BUILD_PLATFORM_BUILDER_IMAGE:latest" \
+    --cache-from "$BUILD_PLATFORM_BUILDER_IMAGE:$tag" \
+    --cache-from "$registry/$BUILD_PLATFORM_BUILDER_IMAGE:latest" \
+    --cache-from "$registry/$BUILD_PLATFORM_BUILDER_IMAGE:$tag" \
     --cache-to type=inline \
-    --tag "$registry/$BUILDER_IMAGE:$tag" \
+    --tag "$registry/$BUILD_PLATFORM_BUILDER_IMAGE:$tag" \
+    --push \
+    --provenance false \
+    .
+
+docker buildx build \
+    --target builder-target-platform \
+    --builder "$builder" \
+    --platform "$platform" \
+    --build-arg CACHE_DATE \
+    --cache-from "$TARGET_PLATFORM_BUILDER_IMAGE:latest" \
+    --cache-from "$TARGET_PLATFORM_BUILDER_IMAGE:$tag" \
+    --cache-from "$registry/$TARGET_PLATFORM_BUILDER_IMAGE:latest" \
+    --cache-from "$registry/$TARGET_PLATFORM_BUILDER_IMAGE:$tag" \
+    --cache-to type=inline \
+    --tag "$registry/$TARGET_PLATFORM_BUILDER_IMAGE:$tag" \
     --push \
     --provenance false \
     .
@@ -77,12 +93,16 @@ docker buildx build \
     --platform "$platform" \
     --build-arg GIT_REVISION \
     --build-arg CACHE_DATE \
-    --cache-from "$BUILDER_IMAGE:latest" \
-    --cache-from "$BUILDER_IMAGE:$tag" \
+    --cache-from "$BUILD_PLATFORM_BUILDER_IMAGE:latest" \
+    --cache-from "$BUILD_PLATFORM_BUILDER_IMAGE:$tag" \
+    --cache-from "$TARGET_PLATFORM_BUILDER_IMAGE:latest" \
+    --cache-from "$TARGET_PLATFORM_BUILDER_IMAGE:$tag" \
     --cache-from "$FINAL_IMAGE:latest" \
     --cache-from "$FINAL_IMAGE:$tag" \
-    --cache-from "$registry/$BUILDER_IMAGE:latest" \
-    --cache-from "$registry/$BUILDER_IMAGE:$tag" \
+    --cache-from "$registry/$BUILD_PLATFORM_BUILDER_IMAGE:latest" \
+    --cache-from "$registry/$BUILD_PLATFORM_BUILDER_IMAGE:$tag" \
+    --cache-from "$registry/$TARGET_PLATFORM_BUILDER_IMAGE:latest" \
+    --cache-from "$registry/$TARGET_PLATFORM_BUILDER_IMAGE:$tag" \
     --cache-from "$registry/$FINAL_IMAGE:latest" \
     --cache-from "$registry/$FINAL_IMAGE:$tag" \
     --cache-to type=inline \
diff --git a/devel/copy-images b/devel/copy-images
index a9c372e5..b7a502ca 100755
--- a/devel/copy-images
+++ b/devel/copy-images
@@ -33,7 +33,8 @@ if [[ "$tag" = "" ]]; then
     exit 1
 fi
 
-BUILDER_IMAGE=nextstrain/base-builder
+BUILD_PLATFORM_BUILDER_IMAGE=nextstrain/base-builder-build-platform
+TARGET_PLATFORM_BUILDER_IMAGE=nextstrain/base-builder-target-platform
 FINAL_IMAGE=nextstrain/base
 
 
@@ -77,26 +78,36 @@ copy-image() {
 
 # Copy $tag between registries.
 
+echo "Copying $registry_in/$BUILD_PLATFORM_BUILDER_IMAGE:$tag to $registry_out/$BUILD_PLATFORM_BUILDER_IMAGE:$tag."
+copy-image \
+    "$registry_in/$BUILD_PLATFORM_BUILDER_IMAGE:$tag" \
+    "$registry_out/$BUILD_PLATFORM_BUILDER_IMAGE:$tag"
+
+echo "Copying $registry_in/$TARGET_PLATFORM_BUILDER_IMAGE:$tag to $registry_out/$TARGET_PLATFORM_BUILDER_IMAGE:$tag."
+copy-image \
+    "$registry_in/$TARGET_PLATFORM_BUILDER_IMAGE:$tag" \
+    "$registry_out/$TARGET_PLATFORM_BUILDER_IMAGE:$tag"
+
 echo "Copying $registry_in/$FINAL_IMAGE:$tag to $registry_out/$FINAL_IMAGE:$tag."
 copy-image \
     "$registry_in/$FINAL_IMAGE:$tag" \
     "$registry_out/$FINAL_IMAGE:$tag"
 
-echo "Copying $registry_in/$BUILDER_IMAGE:$tag to $registry_out/$BUILDER_IMAGE:$tag."
-copy-image \
-    "$registry_in/$BUILDER_IMAGE:$tag" \
-    "$registry_out/$BUILDER_IMAGE:$tag"
-
 if [[ "$push_latest" = true ]]; then
     # Copy $tag to latest.
 
+    echo "Copying $registry_in/$BUILD_PLATFORM_BUILDER_IMAGE:$tag to $registry_out/$BUILD_PLATFORM_BUILDER_IMAGE:latest."
+    copy-image \
+        "$registry_in/$BUILD_PLATFORM_BUILDER_IMAGE:$tag" \
+        "$registry_out/$BUILD_PLATFORM_BUILDER_IMAGE:latest"
+
+    echo "Copying $registry_in/$TARGET_PLATFORM_BUILDER_IMAGE:$tag to $registry_out/$TARGET_PLATFORM_BUILDER_IMAGE:latest."
+    copy-image \
+        "$registry_in/$TARGET_PLATFORM_BUILDER_IMAGE:$tag" \
+        "$registry_out/$TARGET_PLATFORM_BUILDER_IMAGE:latest"
+
     echo "Copying $registry_in/$FINAL_IMAGE:$tag to $registry_out/$FINAL_IMAGE:latest."
     copy-image \
         "$registry_in/$FINAL_IMAGE:$tag" \
         "$registry_out/$FINAL_IMAGE:latest"
-
-    echo "Copying $registry_in/$BUILDER_IMAGE:$tag to $registry_out/$BUILDER_IMAGE:latest."
-    copy-image \
-        "$registry_in/$BUILDER_IMAGE:$tag" \
-        "$registry_out/$BUILDER_IMAGE:latest"
 fi
diff --git a/devel/delete-from-ghcr.js b/devel/delete-from-ghcr.js
index 479fe172..1b1dbe6d 100644
--- a/devel/delete-from-ghcr.js
+++ b/devel/delete-from-ghcr.js
@@ -8,7 +8,11 @@
 
 module.exports = async ({octokit, tag}) => {
   org = 'nextstrain';
-  packages = ['base', 'base-builder'];
+  packages = [
+    'base',
+    'base-builder-build-platform',
+    'base-builder-target-platform',
+  ];
 
   // Try all packages before terminating with any errors.
   let errorEncountered = false;
diff --git a/devel/pull-from-registry b/devel/pull-from-registry
index 4a6a0fe0..e371723e 100755
--- a/devel/pull-from-registry
+++ b/devel/pull-from-registry
@@ -17,8 +17,10 @@ while getopts "r:t:" opt; do
     esac
 done
 
-BUILDER_IMAGE=nextstrain/base-builder
+BUILD_PLATFORM_BUILDER_IMAGE=nextstrain/base-builder-build-platform
+TARGET_PLATFORM_BUILDER_IMAGE=nextstrain/base-builder-target-platform
 FINAL_IMAGE=nextstrain/base
 
-docker pull "$registry/$BUILDER_IMAGE:$tag"
+docker pull "$registry/$BUILD_PLATFORM_BUILDER_IMAGE:$tag"
+docker pull "$registry/$TARGET_PLATFORM_BUILDER_IMAGE:$tag"
 docker pull "$registry/$FINAL_IMAGE:$tag"