diff --git a/.circleci/config.yml b/.circleci/config.yml
new file mode 100644
index 0000000..7cd53f6
--- /dev/null
+++ b/.circleci/config.yml
@@ -0,0 +1,32 @@
+version: 2
+jobs:
+  build:
+    docker:
+      # GHC 8.0.2 is the lowest (and so far, only) supported compiler version.
+      - image: fpco/stack-build:lts-9.21
+    steps:
+      - checkout
+      - restore_cache:
+          keys:
+            - stack-ghc-{{ checksum "stack.yaml" }}
+      - restore_cache:
+          keys:
+            - stack-deps-{{ checksum "package.yaml" }}
+      - run:
+          name: Set up Stack
+          command: stack setup --no-terminal --no-reinstall
+      - save_cache:
+          key: stack-ghc-{{ checksum "stack.yaml" }}
+          paths:
+            - /root/.stack
+      - run:
+          name: Install dependencies
+          command: stack build --skip-ghc-check --no-terminal --test --only-dependencies
+      - save_cache:
+          key: stack-deps-{{ checksum "package.yaml" }}
+          paths:
+            - /root/.stack
+            - .stack-work
+      - run:
+          name: Tests
+          command: stack test --skip-ghc-check --no-terminal
diff --git a/circle.yml b/circle.yml
deleted file mode 100644
index d182dcb..0000000
--- a/circle.yml
+++ /dev/null
@@ -1,22 +0,0 @@
-dependencies:
-  cache_directories:
-    - "~/.cabal"
-    - "~/.local"
-    - "~/.stack"
-    - ".stack-work"
-  pre:
-    - wget -q -O- https://s3.amazonaws.com/download.fpcomplete.com/ubuntu/fpco.key | sudo apt-key add -
-    - echo 'deb http://download.fpcomplete.com/ubuntu/trusty stable main'|sudo tee /etc/apt/sources.list.d/fpco.list
-    - sudo apt-get update
-    - sudo apt-get install -y stack
-  override:
-    - stack --no-terminal setup
-    - stack --no-terminal build --haddock --test --only-dependencies -j1
-
-test:
-  override:
-    - stack --no-terminal build --test --pedantic
-    - stack --no-terminal test
-    - stack --no-terminal haddock
-  post:
-    - mv .stack-work/dist/x86_64-linux/Cabal-1.24.2.0/doc/html/graphql-api $CIRCLE_ARTIFACTS/
diff --git a/stack.yaml b/stack.yaml
index 27ac9a4..057807e 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,8 +1,10 @@
-resolver: nightly-2017-01-25
+# GHC 8.0.2 is the lowest (and currently, only) supported compiler version.
+resolver: lts-9.21
 
 packages:
   - "."
   - "./docs/source/tutorial"
   - "./graphql-wai"
 
-extra-deps: [protolude-0.2]
+extra-deps:
+  - protolude-0.2