diff --git a/.circleci/config.yml b/.circleci/config.yml
index 4c1ebe8163..9eb44c96af 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -11,7 +11,9 @@ jobs:
       - restore_cache:
           key: composer-{{ checksum "composer.json" }}-{{ checksum "composer.lock" }}
       - restore_cache:
-          key: npm-{{ checksum "package.json" }}
+          keys:
+            - npm-{{ checksum "package-lock.json" }}
+            - npm- # fallback to most recent npm-* if not found by checksum
       - run:
           name: "Set up test environment"
           command: |
@@ -33,9 +35,9 @@ jobs:
           paths:
             - vendor
       - save_cache:
-          key: npm-{{ checksum "package.json" }}
+          key: npm-{{ checksum "package-lock.json" }}
           paths:
-            - node_modules
+            - ~/.npm
       - run:
           name: "Composer security check"
           command: |
diff --git a/RoboFile.php b/RoboFile.php
index 0b74a4646d..190b592564 100644
--- a/RoboFile.php
+++ b/RoboFile.php
@@ -8,7 +8,7 @@ class RoboFile extends \Robo\Tasks {
     return $this->taskExecStack()
       ->stopOnFail()
       ->exec('./composer.phar install')
-      ->exec('npm ci')
+      ->exec('npm ci --prefer-offline')
       ->run();
   }
 
diff --git a/build.sh b/build.sh
index 8b2d496da5..7fc1ab0a58 100755
--- a/build.sh
+++ b/build.sh
@@ -19,7 +19,7 @@ mkdir $plugin_name
 # Production assets.
 echo '[BUILD] Generating production CSS and JS assets'
 rm -rf node_modules
-npm ci
+npm ci --prefer-offline
 ./do compile:all --env production
 
 # Dependency injection container cache.