diff --git a/.vscode/settings.json b/.vscode/settings.json
index 6deace9..f0f2ef7 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,3 +1,22 @@
 {
+  "biome.lspBin": "./node_modules/.bin/biome",
+  "[javascript]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[typescript]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[javascriptreact]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[typescriptreact]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[json]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[jsonc]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
   "cSpell.words": ["delvtech"]
 }
diff --git a/biome.jsonc b/biome.jsonc
index 9e370ac..226325d 100644
--- a/biome.jsonc
+++ b/biome.jsonc
@@ -22,7 +22,10 @@
 
     "rules": {
       "style": {
-        "noNonNullAssertion": "info"
+        "noNonNullAssertion": {
+          "level": "info",
+          "fix": "none"
+        }
       },
       "suspicious": {
         "noExplicitAny": "info"
diff --git a/packages/evm-client/src/contract/utils/arrayToFriendly.test.ts b/packages/evm-client/src/contract/utils/arrayToFriendly.test.ts
index b1a5228..1b00fbe 100644
--- a/packages/evm-client/src/contract/utils/arrayToFriendly.test.ts
+++ b/packages/evm-client/src/contract/utils/arrayToFriendly.test.ts
@@ -53,7 +53,7 @@ describe("arrayToFriendly", () => {
   });
 });
 
-export const exampleAbi = [
+const exampleAbi = [
   {
     inputs: [
       { name: "", type: "address" },
diff --git a/packages/evm-client/src/contract/utils/arrayToObject.test.ts b/packages/evm-client/src/contract/utils/arrayToObject.test.ts
index 42c8fa8..732a811 100644
--- a/packages/evm-client/src/contract/utils/arrayToObject.test.ts
+++ b/packages/evm-client/src/contract/utils/arrayToObject.test.ts
@@ -40,7 +40,7 @@ describe("arrayToObject", () => {
   });
 });
 
-export const exampleAbi = [
+const exampleAbi = [
   {
     inputs: [
       { name: "", type: "address" },
diff --git a/packages/evm-client/src/contract/utils/objectToArray.test.ts b/packages/evm-client/src/contract/utils/objectToArray.test.ts
index fcedf5b..bcaaa8b 100644
--- a/packages/evm-client/src/contract/utils/objectToArray.test.ts
+++ b/packages/evm-client/src/contract/utils/objectToArray.test.ts
@@ -48,7 +48,7 @@ describe("objectToArray", () => {
   expect(emptyArrayFromUndefined).toEqual([]);
 });
 
-export const exampleAbi = [
+const exampleAbi = [
   {
     inputs: [
       { name: "", type: "address" },
diff --git a/packages/evm-client/src/network/stubs/NetworkStub.ts b/packages/evm-client/src/network/stubs/NetworkStub.ts
index 645af39..0b09112 100644
--- a/packages/evm-client/src/network/stubs/NetworkStub.ts
+++ b/packages/evm-client/src/network/stubs/NetworkStub.ts
@@ -96,7 +96,7 @@ export class NetworkStub implements Network {
   getBalance(...args: NetworkGetBalanceArgs): Promise<bigint> {
     if (!this.getBalanceStub) {
       throw new Error(
-        `The getBalance function must be stubbed first:\n\tcontract.stubGetBalance()`,
+        "The getBalance function must be stubbed first:\n\tcontract.stubGetBalance()",
       );
     }
     return this.getBalanceStub(args);
@@ -105,7 +105,7 @@ export class NetworkStub implements Network {
   getBlock(...args: NetworkGetBlockArgs): Promise<Block | undefined> {
     if (!this.getBlockStub) {
       throw new Error(
-        `The getBlock function must be stubbed first:\n\tcontract.stubGetBlock()`,
+        "The getBlock function must be stubbed first:\n\tcontract.stubGetBlock()",
       );
     }
     return this.getBlockStub(args);
@@ -114,7 +114,7 @@ export class NetworkStub implements Network {
   getChainId(): Promise<number> {
     if (!this.getChainIdStub) {
       throw new Error(
-        `The getChainId function must be stubbed first:\n\tcontract.stubGetChainId()`,
+        "The getChainId function must be stubbed first:\n\tcontract.stubGetChainId()",
       );
     }
     return this.getChainIdStub();
@@ -125,7 +125,7 @@ export class NetworkStub implements Network {
   ): Promise<Transaction | undefined> {
     if (!this.getTransactionStub) {
       throw new Error(
-        `The getTransaction function must be stubbed first:\n\tcontract.stubGetTransaction()`,
+        "The getTransaction function must be stubbed first:\n\tcontract.stubGetTransaction()",
       );
     }
     return this.getTransactionStub(args);
@@ -134,6 +134,7 @@ export class NetworkStub implements Network {
   async waitForTransaction(
     ...[hash, { timeout = 60_000 } = {}]: NetworkWaitForTransactionArgs
   ): Promise<TransactionReceipt | undefined> {
+    // biome-ignore lint/suspicious/noAsyncPromiseExecutor: special case for testing
     return new Promise(async (resolve) => {
       let transaction: Transaction | undefined;