diff --git a/.gitmodules b/.gitmodules
index 5c6b89f7..bf4ea1cf 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,3 +4,6 @@
 [submodule "contracts/lib/chainlink-brownie-contracts"]
 	path = contracts/lib/chainlink-brownie-contracts
 	url = https://github.com/smartcontractkit/chainlink-brownie-contracts
+[submodule "contracts/lib/openzeppelin-contracts"]
+	path = contracts/lib/openzeppelin-contracts
+	url = https://github.com/OpenZeppelin/openzeppelin-contracts
diff --git a/contracts/.env.example b/contracts/.env.example
deleted file mode 100644
index 8b137891..00000000
--- a/contracts/.env.example
+++ /dev/null
@@ -1 +0,0 @@
-
diff --git a/contracts/foundry.lock b/contracts/foundry.lock
index eef3d685..ec195333 100644
--- a/contracts/foundry.lock
+++ b/contracts/foundry.lock
@@ -1,5 +1,11 @@
 {
   "lib/forge-std": {
     "rev": "3b20d60d14b343ee4f908cb8079495c07f5e8981"
+  },
+  "lib\\openzeppelin-contracts": {
+    "tag": {
+      "name": "v5.5.0",
+      "rev": "fcbae5394ae8ad52d8e580a3477db99814b9d565"
+    }
   }
 }
\ No newline at end of file
diff --git a/contracts/foundry.toml b/contracts/foundry.toml
index 64d81706..6f0d7112 100644
--- a/contracts/foundry.toml
+++ b/contracts/foundry.toml
@@ -2,6 +2,7 @@
 src = "src"
 out = "out"
 libs = ["lib"]
-solc_version = '0.8.13'
+solc_version = '0.8.20'
+   remappings = ['@openzeppelin/=lib/openzeppelin-contracts/']
 # See more config options https://github.com/foundry-rs/foundry/blob/master/crates/config/README.md#all-options
 # forge create --rpc-url https://eth-sepolia.g.alchemy.com/v2/nnY0qPUQLYsUvb5BKJM5bh81sI6O0PQG   --private-key fba7342ef6879df2c735644c734ea69c140f423d84eb2d53fbdfd53fd5d7c586  src/Token.sol:MyToken --legacy
\ No newline at end of file
diff --git a/contracts/lib/openzeppelin-contracts b/contracts/lib/openzeppelin-contracts
new file mode 160000
index 00000000..fcbae539
--- /dev/null
+++ b/contracts/lib/openzeppelin-contracts
@@ -0,0 +1 @@
+Subproject commit fcbae5394ae8ad52d8e580a3477db99814b9d565
diff --git a/contracts/src/Chainvoice.sol b/contracts/src/Chainvoice.sol
index 042397b4..63e9e6df 100644
--- a/contracts/src/Chainvoice.sol
+++ b/contracts/src/Chainvoice.sol
@@ -1,15 +1,14 @@
 // SPDX-License-Identifier: Unlicense
-pragma solidity ^0.8.13;
+pragma solidity ^0.8.20;
+
+
+import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 
-interface IERC20 {
-    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
-    function balanceOf(address account) external view returns (uint256);
-    function allowance(address owner, address spender) external view returns (uint256);
-}
 
 contract Chainvoice {
-    // ========== Errors ==========
-    // Existing
+    using SafeERC20 for IERC20;
+    // Errors
     error MixedTokenBatch();
     error InvalidBatchSize();
     error AlreadySettled();
@@ -103,16 +102,6 @@ contract Chainvoice {
     // Constants
     uint256 public constant MAX_BATCH = 50;
 
-    // ========== Internal Utils ==========
-    function _isERC20(address token) internal view returns (bool) {
-        if (token == address(0)) return false;
-        if (token.code.length == 0) return false;
-        (bool success, ) = token.staticcall(
-            abi.encodeWithSignature("balanceOf(address)", address(this))
-        );
-        return success;
-    }
-
     // ========== Single-invoice create ==========
     function createInvoice(
         address to,
@@ -258,12 +247,11 @@ contract Chainvoice {
             }
             accumulatedFees += fee;
 
-            bool transferSuccess = IERC20(invoice.tokenAddress).transferFrom(
+            IERC20(invoice.tokenAddress).safeTransferFrom(
                 msg.sender,
                 invoice.from,
                 invoice.amountDue
             );
-            if (!transferSuccess) revert TokenTransferFailed();
         }
 
         emit InvoicePaid(
@@ -331,8 +319,7 @@ contract Chainvoice {
 
             for (uint256 i = 0; i < n; i++) {
                 InvoiceDetails storage inv = invoices[invoiceIds[i]];
-                bool ok = erc20.transferFrom(msg.sender, inv.from, inv.amountDue);
-                if (!ok) revert TokenTransferFailed();
+                erc20.safeTransferFrom(msg.sender, inv.from, inv.amountDue);
                 emit InvoicePaid(inv.id, inv.from, inv.to, inv.amountDue, token);
             }
         }
diff --git a/contracts/test/Chainvoice.t.sol b/contracts/test/Chainvoice.t.sol
index 2abb1ce9..23753d01 100644
--- a/contracts/test/Chainvoice.t.sol
+++ b/contracts/test/Chainvoice.t.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: Unlicense
-pragma solidity ^0.8.13;
+pragma solidity ^0.8.20;
 
 import {Test} from "forge-std/Test.sol";
 import {console} from "forge-std/console.sol";