diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a475c34..742948d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -21,5 +21,6 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
       - run: npm ci
+      - run: npx tsc --noEmit --lib es2015 types/index.d.ts
       - run: npm run build --if-present
       - run: npm test
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4b5fead..51ed400 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 All notable changes to omise-node project will be documented in this file.
 Use [Semantic Versioning](http://semver.org/).
 
+## 0.8.2 - 2020-07-23
+- Add missing typescript definitions.
+
 ## 0.8.1 - 2020-07-20
 - Add `Charge.expire` API.
 
diff --git a/package.json b/package.json
index ab2a4c3..808b622 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "omise",
-  "version": "0.8.1",
+  "version": "0.8.2",
   "description": "Omise Node.js bindings",
   "main": "index.js",
   "types": "types/index.d.ts",
diff --git a/types/index.d.ts b/types/index.d.ts
index 50cbffb..e06b640 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -53,6 +53,14 @@ declare namespace Omise {
       country: string;
       zero_interest_installments: boolean;
     }
+
+    interface IRequest {
+      chain_enabled?: boolean;
+      chain_return_uri?: string;
+      metadata_export_keys?: object;
+      webhook_uri?: string;
+      zero_interest_installments?: boolean;
+    }
   }
 
   export namespace Balance {
@@ -119,7 +127,7 @@ declare namespace Omise {
       capture(chargeID: string, callback?: ResponseCallback<ICharge>): Bluebird<ICharge>;
       reverse(chargeID: string, callback?: ResponseCallback<ICharge>): Bluebird<ICharge>;
       expire(chargeID: string, callback?: ResponseCallback<ICharge>): Bluebird<ICharge>;
-      createRefund(chargeID: string, callback?: ResponseCallback<IRefundResponse>): Bluebird<IRefundResponse>;
+      createRefund(chargeID: string, req: IRefundRequest, callback?: ResponseCallback<IRefundResponse>): Bluebird<IRefundResponse>;
       listRefunds(chargeID: string, callback?: ResponseCallback<IListRefundResponse>): Bluebird<IListRefundResponse>;
       retrieveRefund(chargeID: string, refundID: string, callback?: ResponseCallback<IRefundResponse>): Bluebird<IRefundResponse>;
     }
@@ -166,6 +174,12 @@ declare namespace Omise {
       data: ICharge[];
     }
 
+    interface IRefundRequest {
+      amount: number;
+      metadata?: { [key: string]: any };
+      void?: boolean
+    }
+
     interface IRefundResponse extends IBaseResponse {
       amount: number;
       currency: string;
@@ -173,6 +187,7 @@ declare namespace Omise {
       transaction: string;
       created: string;
       voided: boolean;
+      metadata?: { [key: string]: any };
     }
   }