diff --git a/.github/workflows/danger.yml b/.github/workflows/danger.yml
new file mode 100644
index 0000000000..37c486643f
--- /dev/null
+++ b/.github/workflows/danger.yml
@@ -0,0 +1,15 @@
+name: "Danger"
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, edited]
+
+jobs:
+  build:
+    name: Changelogs
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+      - run: npx danger@9.1.8 ci
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/dangerfile.js b/dangerfile.js
new file mode 100644
index 0000000000..7ba76aa93d
--- /dev/null
+++ b/dangerfile.js
@@ -0,0 +1,27 @@
+const files = danger.git.modified_files;
+const hasChangelog = files.indexOf("CHANGELOG.md") !== -1;
+const hasPyChangelog = files.indexOf("py/CHANGELOG.md") !== -1;
+
+const ERROR_MESSAGE =
+  "Please consider adding a changelog entry for the next release.";
+
+const DETAILS = `
+For changes exposed to the _Python package_, please add an entry to \`py/CHANGELOG.md\`. This includes, but is not limited to event normalization, PII scrubbing, and the protocol.
+
+For changes to the _Relay server_, please add an entry to \`CHANGELOG.md\` under the following heading:
+ 1. **Features**: For new user-visible functionality.
+ 2. **Bug Fixes**: For user-visible bug fixes.
+ 3. **Internal**: For features and bug fixes in internal operation, especially processing mode.
+
+If none of the above apply, you can opt out by adding _#skip-changelog_ to the PR description.
+`;
+
+const skipChangelog =
+  danger.github && danger.github.pr.body.includes("#skip-changelog");
+
+if (!hasChangelog && !hasPyChangelog && !skipChangelog) {
+  fail(ERROR_MESSAGE);
+  markdown(DETAILS);
+} else {
+  message("Opted out of changelogs due to #skip-changelog.");
+}