diff --git a/.circleci/config.yml b/.circleci/config.yml
index 43e9a03..a740348 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,30 +1,35 @@
 version: 2
 
-jobs:
-  build:
-    docker:
-      # node-browsers come with java pre-installed
-      - image: circleci/node:6.14-browsers
-    working_directory: ~/openzipkin/web
+aliases:
+  # install latest versions of packages
+  - &install-latest-dependencies
+  |
+    npm install && \
+    npm install --save zipkin@latest \
+      zipkin-context-cls@latest \
+      zipkin-instrumentation-cujojs-rest@latest \
+      zipkin-instrumentation-express@latest \
+      zipkin-instrumentation-fetch@latest \
+      zipkin-transport-http@latest
+
+defaults: &defaults
+  working_directory: ~/openzipkin/web
+  docker:
+    - image: circleci/node:6.14-browsers
 
+jobs:
+  build-sampled:
+    <<: *defaults
     steps:
       - checkout:
           path: ~/openzipkin
-      - run: npm install
-      # install latest versions of packages
-      - run: |
-          npm install --save zipkin@latest \
-                             zipkin-context-cls@latest \
-                             zipkin-instrumentation-cujojs-rest@latest \
-                             zipkin-instrumentation-express@latest \
-                             zipkin-instrumentation-fetch@latest \
-                             zipkin-transport-http@latest
+      - run: *install-latest-dependencies
       - run: curl -sSL https://zipkin.io/quickstart.sh | bash -s
       - run:
           background: true
           command: java -jar zipkin.jar
       # block until zipkin is available
-      - run: wget --retry-connrefused -T 60 -O /dev/null http://127.0.0.1:9411/health
+      - run: wget --retry-connrefused -T 60 -O /dev/null --header="X-B3-TraceId: a2fb4a1d1a96d312" --header="X-B3-SpanId: a2fb4a1d1a96d312" --header="X-B3-Sampled: 1" http://127.0.0.1:9411/health
       # start both processes in the background, but don't use composer as it dies
       - run:
           background: true
@@ -34,17 +39,45 @@ jobs:
       - run: |
           # wait just in case
           sleep 1
-          traces="$(curl -s 127.0.0.1:9411/api/v2/traces)"
+          traces="$(curl -s 127.0.0.1:9411/api/v2/trace/a2fb4a1d1a96d312)"
           echo "queried traces: $traces"
           count=$(echo "$traces" | jq '.[0] | length')
           echo "count: $count"
           test $count -ge 2
 
+  build-unsampled:
+    <<: *defaults
+    steps:
+      - checkout:
+          path: ~/openzipkin
+      - run: *install-latest-dependencies
+      - run: curl -sSL https://zipkin.io/quickstart.sh | bash -s
+      - run:
+          background: true
+          command: java -jar zipkin.jar
+      # block until zipkin is available
+      - run: wget --retry-connrefused -T 60 -O /dev/null --header="X-B3-TraceId: a2fb4a1d1a96d313" --header="X-B3-SpanId: a2fb4a1d1a96d313" --header="X-B3-Sampled: 0" http://127.0.0.1:9411/health
+      # start both processes in the background, but don't use composer as it dies
+      - run:
+          background: true
+          command: npm start
+      # hit the frontend which calls the backend
+      - run: wget -v --retry-connrefused -T 5 -O /dev/null 127.0.0.1:8081
+      - run: |
+          # wait just in case
+          sleep 1
+          traces="$(curl -s 127.0.0.1:9411/api/v2/trace/a2fb4a1d1a96d312)"
+          echo "queried traces: $traces"
+          count=$(echo "$traces" | jq '.[0] | length')
+          echo "count: $count"
+          test $count -ge 0
+
 workflows:
   version: 2
   commit:
     jobs:
-      - build
+      - build-sampled
+      - build-unsampled
   nightly:
     triggers:
       - schedule: