diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 856d67e..cb39269 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,37 +1,25 @@
 name: Tests
 
-on: [pull_request]
+on: pull_request
 
 jobs:
   test:
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout project
         uses: actions/checkout@v3
 
       - name: Specify node version
-        uses: actions/setup-node@v2-beta
+        uses: actions/setup-node@v3
         with:
           node-version: 16
-
-      - name: Use npm caches
-        uses: actions/cache@v2
-        with:
-          path: ~/.npm
-          key: ${{ runner.os }}-npm-${{ hashFiles('**/package-lock.json') }}
-          restore-keys: |
-            ${{ runner.os }}-npm-
-
-      - name: Use node_modules caches
-        id: cache-nm
-        uses: actions/cache@v2
-        with:
-          path: node_modules
-          key: ${{ runner.os }}-nm-${{ hashFiles('package-lock.json') }}
+          cache: 'npm'
 
       - name: Install node_modules
-        if: steps.cache-nm.outputs.cache-hit != 'true'
         run: npm install
 
       - name: Run tests
         run: npm test
+
+      - name: Run type checks
+        run: npm run type-check
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3c3629e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+node_modules
diff --git a/index.ts b/index.ts
index c334683..5aa3966 100644
--- a/index.ts
+++ b/index.ts
@@ -12,7 +12,7 @@ type UTXO = {
   txid: string;
   vout: number;
   WIF: string;
-  is_taproot: bool;
+  is_taproot: boolean;
 };
 
 type Target = {
@@ -21,6 +21,11 @@ type Target = {
   value?: number;
 };
 
+type SilentPaymentGroup = {
+  Bscan: Buffer;
+  BmValues: Array<[Buffer, number | undefined]>;
+};
+
 const G = Buffer.from("0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798", "hex");
 
 export class SilentPayment {
@@ -35,7 +40,7 @@ export class SilentPayment {
   createTransaction(utxos: UTXO[], targets: Target[]): Target[] {
     const ret: Target[] = [];
 
-    let silentPaymentGroups = [];
+    let silentPaymentGroups: Array<SilentPaymentGroup> = [];
     for (const target of targets) {
       if (!target.silentPaymentCode) {
         ret.push(target); // passthrough
@@ -96,7 +101,7 @@ export class SilentPayment {
 
   static _outpointsHash(parameters: UTXO[]): Buffer {
     let bufferConcat = Buffer.alloc(0);
-    let outpoints = [];
+    let outpoints: Array<Buffer> = [];
     for (const parameter of parameters) {
       outpoints.push(Buffer.concat([Buffer.from(parameter.txid, "hex").reverse(), SilentPayment._ser32(parameter.vout).reverse()]));
     }
diff --git a/package-lock.json b/package-lock.json
index 8363518..fab6120 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -20,11 +20,13 @@
         "ts-node": "^10.9.1"
       },
       "devDependencies": {
+        "@tsconfig/recommended": "^1.0.2",
         "@types/create-hash": "^1.2.2",
         "@types/node": "^20.2.5",
         "babel-jest": "^29.5.0",
         "jest": "^29.5.0",
-        "prettier": "2.8.8"
+        "prettier": "2.8.8",
+        "typescript": "^5.1.6"
       }
     },
     "node_modules/@ampproject/remapping": {
@@ -2478,6 +2480,12 @@
       "resolved": "https://registry.npmjs.org/@tsconfig/node16/-/node16-1.0.4.tgz",
       "integrity": "sha512-vxhUy4J8lyeyinH7Azl1pdd43GJhZH/tP2weN8TntQblOY+A0XbT8DJk1/oCPuOOyg/Ja757rG0CgHcWC8OfMA=="
     },
+    "node_modules/@tsconfig/recommended": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/@tsconfig/recommended/-/recommended-1.0.2.tgz",
+      "integrity": "sha512-dbHBtbWBOjq0/otpopAE02NT2Cm05Qe2JsEKeCf/wjSYbI2hz8nCqnpnOJWHATgjDz4fd3dchs3Wy1gQGjfN6w==",
+      "dev": true
+    },
     "node_modules/@types/babel__core": {
       "version": "7.20.1",
       "resolved": "https://registry.npmjs.org/@types/babel__core/-/babel__core-7.20.1.tgz",
@@ -6308,10 +6316,9 @@
       "integrity": "sha512-7uc1O8h1M1g0rArakJdf0uLRSSgFcYexrVoKo+bzJd32gd4gDy2L/Z+8/FjPnU9ydY3pEnVPtr9FyscYY60K1g=="
     },
     "node_modules/typescript": {
-      "version": "5.1.3",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.1.3.tgz",
-      "integrity": "sha512-XH627E9vkeqhlZFQuL+UsyAXEnibT0kWR2FWONlr4sTjvxyJYnyefgrkyECLzM5NenmKzRAy2rR/OlYLA1HkZw==",
-      "peer": true,
+      "version": "5.1.6",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.1.6.tgz",
+      "integrity": "sha512-zaWCozRZ6DLEWAWFrVDz1H6FVXzUSfTy5FUMWsQlU8Ym5JP9eO4xkTIROFCQvhQf61z6O/G6ugw3SgAnvvm+HA==",
       "bin": {
         "tsc": "bin/tsc",
         "tsserver": "bin/tsserver"
@@ -8330,6 +8337,12 @@
       "resolved": "https://registry.npmjs.org/@tsconfig/node16/-/node16-1.0.4.tgz",
       "integrity": "sha512-vxhUy4J8lyeyinH7Azl1pdd43GJhZH/tP2weN8TntQblOY+A0XbT8DJk1/oCPuOOyg/Ja757rG0CgHcWC8OfMA=="
     },
+    "@tsconfig/recommended": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/@tsconfig/recommended/-/recommended-1.0.2.tgz",
+      "integrity": "sha512-dbHBtbWBOjq0/otpopAE02NT2Cm05Qe2JsEKeCf/wjSYbI2hz8nCqnpnOJWHATgjDz4fd3dchs3Wy1gQGjfN6w==",
+      "dev": true
+    },
     "@types/babel__core": {
       "version": "7.20.1",
       "resolved": "https://registry.npmjs.org/@types/babel__core/-/babel__core-7.20.1.tgz",
@@ -11172,10 +11185,9 @@
       "integrity": "sha512-7uc1O8h1M1g0rArakJdf0uLRSSgFcYexrVoKo+bzJd32gd4gDy2L/Z+8/FjPnU9ydY3pEnVPtr9FyscYY60K1g=="
     },
     "typescript": {
-      "version": "5.1.3",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.1.3.tgz",
-      "integrity": "sha512-XH627E9vkeqhlZFQuL+UsyAXEnibT0kWR2FWONlr4sTjvxyJYnyefgrkyECLzM5NenmKzRAy2rR/OlYLA1HkZw==",
-      "peer": true
+      "version": "5.1.6",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.1.6.tgz",
+      "integrity": "sha512-zaWCozRZ6DLEWAWFrVDz1H6FVXzUSfTy5FUMWsQlU8Ym5JP9eO4xkTIROFCQvhQf61z6O/G6ugw3SgAnvvm+HA=="
     },
     "unicode-canonical-property-names-ecmascript": {
       "version": "2.0.0",
diff --git a/package.json b/package.json
index 4f8a20d..cdc0bd5 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,8 @@
   "description": "",
   "main": "index.ts",
   "scripts": {
-    "test": "jest tests/"
+    "test": "jest tests/",
+    "type-check": "tsc --noEmit"
   },
   "author": "overtorment",
   "license": "MIT",
@@ -20,10 +21,12 @@
     "ts-node": "^10.9.1"
   },
   "devDependencies": {
+    "@tsconfig/recommended": "^1.0.2",
     "@types/create-hash": "^1.2.2",
     "@types/node": "^20.2.5",
     "babel-jest": "^29.5.0",
     "jest": "^29.5.0",
-    "prettier": "2.8.8"
+    "prettier": "2.8.8",
+    "typescript": "^5.1.6"
   }
 }
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..df325e4
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,7 @@
+{
+  "extends": "@tsconfig/recommended/tsconfig.json",
+  "include": [
+    "index.ts",
+    "noble_ecc.ts"
+  ],
+}