diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..4451503
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,18 @@
+name: CI
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [20, 22]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+      - run: npm install --no-audit --no-fund
+      - run: npm test
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..05b804b
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Nicholas Ashkar
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/package.json b/package.json
index 5a6d173..abc9639 100644
--- a/package.json
+++ b/package.json
@@ -6,5 +6,6 @@
   "bin": { "mrr": "./index.js" },
   "keywords": ["mrr", "revenue", "indie-hacker", "saas", "cli", "tracker"],
   "license": "MIT",
-  "engines": { "node": ">=18" }
+  "scripts": { "test": "node --test" },
+  "engines": { "node": ">=20" }
 }
diff --git a/test/smoke.test.js b/test/smoke.test.js
new file mode 100644
index 0000000..a2eba06
--- /dev/null
+++ b/test/smoke.test.js
@@ -0,0 +1,6 @@
+import { test } from 'node:test'
+import { execFileSync } from 'node:child_process'
+import { fileURLToPath } from 'node:url'
+import { dirname, join } from 'node:path'
+const root = join(dirname(fileURLToPath(import.meta.url)), '..')
+test('entry is valid JavaScript', () => { execFileSync('node', ['--check', join(root, 'index.js')]) })