diff --git a/packages/api-kit/src/SafeApiKit.ts b/packages/api-kit/src/SafeApiKit.ts
index 2dc05fd15..d757e8be8 100644
--- a/packages/api-kit/src/SafeApiKit.ts
+++ b/packages/api-kit/src/SafeApiKit.ts
@@ -659,7 +659,7 @@ class SafeApiKit {
 
   async addMessage(
     safeAddress: string,
-    { message, safeAppId, signature }: AddMessageProps
+    { message, safeAppId = 0, signature }: AddMessageProps
   ): Promise<void> {
     if (!safeAddress) {
       throw new Error('Invalid safeAddress')
diff --git a/packages/api-kit/src/types/safeTransactionServiceTypes.ts b/packages/api-kit/src/types/safeTransactionServiceTypes.ts
index dd383c938..00a4880e6 100644
--- a/packages/api-kit/src/types/safeTransactionServiceTypes.ts
+++ b/packages/api-kit/src/types/safeTransactionServiceTypes.ts
@@ -301,6 +301,6 @@ export type EIP712TypedData = {
 
 export type AddMessageProps = {
   message: string | EIP712TypedData
-  safeAppId: number
+  safeAppId?: number
   signature: string
 }
diff --git a/packages/api-kit/tests/e2e/addMessage.test.ts b/packages/api-kit/tests/e2e/addMessage.test.ts
new file mode 100644
index 000000000..5a89cc2f8
--- /dev/null
+++ b/packages/api-kit/tests/e2e/addMessage.test.ts
@@ -0,0 +1,45 @@
+import { Signer } from '@ethersproject/abstract-signer'
+import SafeApiKit, { AddSafeDelegateProps } from '@safe-global/api-kit/index'
+import chai from 'chai'
+import chaiAsPromised from 'chai-as-promised'
+import config from '../utils/config'
+import { getServiceClient } from '../utils/setupServiceClient'
+import { ethers } from 'ethers'
+
+chai.use(chaiAsPromised)
+
+let safeApiKit: SafeApiKit
+let signer: Signer
+
+const MESSAGE = 'I am the owner of this safe'
+
+describe.only('addMessage', () => {
+  before(async () => {
+    ;({ safeApiKit, signer } = await getServiceClient(
+      '0x4f3edf983ac636a65a842ce7c78d9aa706d3b113bce9c46f30d7d21715b23b1d'
+    ))
+  })
+
+  it('should fail if safeAddress is empty', async () => {
+    await chai
+      .expect(
+        safeApiKit.addMessage('', {
+          message: MESSAGE,
+          signature: '0x'
+        })
+      )
+      .to.be.rejectedWith('Invalid safeAddress')
+  })
+
+  it('should allow to add an offchain message', async () => {
+    console.log(await signer.getAddress())
+    const signature = await signer.signMessage(MESSAGE)
+
+    await chai.expect(
+      safeApiKit.addMessage('0x9D1E7371852a9baF631Ea115b9815deb97cC3205', {
+        message: MESSAGE,
+        signature
+      })
+    ).to.be.fulfilled
+  })
+})