diff --git a/.circleci/config.yml b/.circleci/config.yml
index ba3135c009aec9459a4f0623fab72eeced6f6ea2..b19036322fc08d11235144c32ff74c7f9f0aa5a8 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -74,6 +74,15 @@ jobs:
             - paymentserver-v1-{{ checksum "stack.yaml" }}-{{ checksum "PaymentServer.cabal" }}
             - paymentserver-v1-{{ checksum "stack.yaml" }}
 
+      - run:
+          name: "Build Dependencies"
+          command: |
+            nix-shell shell.nix --run "stack build --only-dependencies --interleaved-output"
+
+          # Give it a good long while.  stripe-core, in particular, can take a
+          # while to build.
+          no_output_timeout: "20m"
+
       - run:
           name: "Run Tests"
           command: |