1 files changed, 6 insertions, 0 deletions
diff --git a/packages/0x.js/src/abstract/balance_and_allowance_fetcher.ts b/packages/0x.js/src/abstract/balance_and_allowance_fetcher.ts
new file mode 100644
index 000000000..f7b1183f1
--- /dev/null
+++ b/packages/0x.js/src/abstract/balance_and_allowance_fetcher.ts
@@ -0,0 +1,6 @@
+import { BigNumber } from '@0xproject/utils';
+
+export abstract class BalanceAndAllowanceFetcher {
+    public abstract async getBalanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber>;
+    public abstract async getProxyAllowanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber>;
+}