diff --git a/app/Http/Requests/Payment/StorePaymentRequest.php b/app/Http/Requests/Payment/StorePaymentRequest.php
index 2deffed782ec..c74f91d78ab4 100644
--- a/app/Http/Requests/Payment/StorePaymentRequest.php
+++ b/app/Http/Requests/Payment/StorePaymentRequest.php
@@ -54,7 +54,10 @@ class StorePaymentRequest extends Request
         if (isset($input['invoices']) && is_array($input['invoices']) !== false) {
             foreach ($input['invoices'] as $key => $value) {
                 $input['invoices'][$key]['invoice_id'] = $this->decodePrimaryKey($value['invoice_id']);
-                $invoices_total += $value['amount'];
+
+                if(array_key_exists('amount', $value))
+                    $invoices_total += $value['amount'];
+
             }
         }
 
@@ -91,12 +94,12 @@ class StorePaymentRequest extends Request
     public function rules()
     {
         $rules = [
-            'amount' => 'numeric|required',
+            'amount' => 'sometimes|numeric',
             'amount' => [new PaymentAmountsBalanceRule(), new ValidCreditsPresentRule()],
             'client_id' => 'bail|required|exists:clients,id',
             'invoices.*.invoice_id' => 'bail|required|distinct|exists:invoices,id',
+            'invoices.*.amount' => 'bail|required',
             'invoices.*.invoice_id' => new ValidInvoicesRules($this->all()),
-            'invoices.*.amount' => 'required',
             'credits.*.credit_id' => 'bail|required|exists:credits,id',
             'credits.*.credit_id' => new ValidCreditsRules($this->all()),
             'credits.*.amount' => ['required', new CreditsSumRule($this->all())],
diff --git a/app/Http/ValidationRules/Payment/ValidInvoicesRules.php b/app/Http/ValidationRules/Payment/ValidInvoicesRules.php
index 0bc63580ebc7..f3a333a091c7 100644
--- a/app/Http/ValidationRules/Payment/ValidInvoicesRules.php
+++ b/app/Http/ValidationRules/Payment/ValidInvoicesRules.php
@@ -57,6 +57,11 @@ class ValidInvoicesRules implements Rule
 
             $unique_array[] = $invoice['invoice_id'];
 
+            if(!array_key_exists('amount', $invoice)){
+                $this->error_msg = ctrans('texts.amount') . " required";
+                return false;
+            }
+
             $inv = Invoice::whereId($invoice['invoice_id'])->first();
 
             if (! $inv) {
diff --git a/app/Http/ValidationRules/Payment/ValidRefundableRequest.php b/app/Http/ValidationRules/Payment/ValidRefundableRequest.php
index b29c6ab06a18..7abba2b7870e 100644
--- a/app/Http/ValidationRules/Payment/ValidRefundableRequest.php
+++ b/app/Http/ValidationRules/Payment/ValidRefundableRequest.php
@@ -79,6 +79,11 @@ class ValidRefundableRequest implements Rule
     {
         $invoice = Invoice::whereId($invoice['invoice_id'])->whereCompanyId($payment->company_id)->withTrashed()->first();
 
+        if(!$invoice){
+            $this->error_msg = "Invoice not found for refund";
+            return false;
+        }
+
         if ($payment->invoices()->exists()) {
             $paymentable_invoice = $payment->invoices->where('id', $invoice->id)->first();
 
diff --git a/app/Http/ValidationRules/PaymentAmountsBalanceRule.php b/app/Http/ValidationRules/PaymentAmountsBalanceRule.php
index 2097b1b77c1d..be8f0d60ec98 100644
--- a/app/Http/ValidationRules/PaymentAmountsBalanceRule.php
+++ b/app/Http/ValidationRules/PaymentAmountsBalanceRule.php
@@ -59,13 +59,17 @@ class PaymentAmountsBalanceRule implements Rule
 
         if (request()->input('credits') && is_array(request()->input('credits'))) {
             foreach (request()->input('credits') as $credit) {
-                $payment_amounts += $credit['amount'];
+                
+                if(array_key_exists('amount', $credit))
+                    $payment_amounts += $credit['amount'];
             }
         }
 
         if (request()->input('invoices') && is_array(request()->input('invoices'))) {
             foreach (request()->input('invoices') as $invoice) {
-                $invoice_amounts += $invoice['amount'];
+ 
+                if(array_key_exists('amount', $invoice))
+                    $invoice_amounts += $invoice['amount'];
             }
         } else {
             return true;
diff --git a/tests/Feature/Payments/StorePaymentValidationTest.php b/tests/Feature/Payments/StorePaymentValidationTest.php
new file mode 100644
index 000000000000..7a4d11a44d58
--- /dev/null
+++ b/tests/Feature/Payments/StorePaymentValidationTest.php
@@ -0,0 +1,167 @@
+<?php
+/**
+ * Invoice Ninja (https://invoiceninja.com).
+ *
+ * @link https://github.com/invoiceninja/invoiceninja source repository
+ *
+ * @copyright Copyright (c) 2021. Invoice Ninja LLC (https://invoiceninja.com)
+ *
+ * @license https://opensource.org/licenses/AAL
+ */
+namespace Tests\Feature\Payments;
+
+use App\DataMapper\ClientSettings;
+use App\Factory\ClientFactory;
+use App\Factory\CreditFactory;
+use App\Factory\InvoiceFactory;
+use App\Factory\InvoiceItemFactory;
+use App\Factory\PaymentFactory;
+use App\Helpers\Invoice\InvoiceSum;
+use App\Models\Client;
+use App\Models\ClientContact;
+use App\Models\Credit;
+use App\Models\Invoice;
+use App\Models\Payment;
+use App\Utils\Traits\MakesHash;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Foundation\Testing\DatabaseTransactions;
+use Illuminate\Foundation\Testing\WithoutEvents;
+use Illuminate\Routing\Middleware\ThrottleRequests;
+use Illuminate\Support\Facades\Session;
+use Illuminate\Validation\ValidationException;
+use Tests\MockAccountData;
+use Tests\MockUnitData;
+use Tests\TestCase;
+
+/**
+ * @test
+ */
+class StorePaymentValidationTest extends TestCase
+{
+    use MakesHash;
+    use DatabaseTransactions;
+    use MockAccountData;
+    use WithoutEvents;
+
+    public function setUp() :void
+    {
+        parent::setUp();
+
+        Session::start();
+
+        $this->faker = \Faker\Factory::create();
+
+        Model::reguard();
+
+        $this->makeTestData();
+
+
+        $this->withoutMiddleware(
+            ThrottleRequests::class
+        );
+    }
+
+
+    public function testValidPayment()
+    {
+
+       $data = [
+            'amount' => 0,
+            'client_id' => $this->client->hashed_id,
+            'invoices' => [
+            ],
+            'date' => '2019/12/12',
+        ];
+
+        $response = false;
+
+        try {
+            $response = $this->withHeaders([
+            'X-API-SECRET' => config('ninja.api_secret'),
+            'X-API-TOKEN' => $this->token,
+        ])->post('/api/v1/payments/', $data);
+        } catch (ValidationException $e) {
+            $message = json_decode($e->validator->getMessageBag(), 1);
+            nlog($e->validator->getMessageBag());
+        }
+
+        $response->assertStatus(200);
+
+    }
+
+
+    public function testValidPaymentWithAmount()
+    {
+
+       $data = [
+            'amount' => 0,
+            'client_id' => $this->client->hashed_id,
+            'invoices' => [
+                [
+                    'invoice_id' => $this->invoice->hashed_id,
+                    'amount' => 10,
+                ],
+            ],
+            'credits' => [
+                [
+                    'credit_id' => $this->credit->hashed_id,
+                    'amount' => 5
+                ]
+            ],
+            'date' => '2019/12/12',
+        ];
+
+        $response = false;
+
+        try {
+            $response = $this->withHeaders([
+            'X-API-SECRET' => config('ninja.api_secret'),
+            'X-API-TOKEN' => $this->token,
+        ])->post('/api/v1/payments/', $data);
+        } catch (ValidationException $e) {
+            $message = json_decode($e->validator->getMessageBag(), 1);
+            nlog($e->validator->getMessageBag());
+        }
+
+        $response->assertStatus(200);
+
+    }
+
+    public function testValidPaymentWithInvalidData()
+    {
+
+        
+       $data = [
+            'amount' => 0,
+            'client_id' => $this->client->hashed_id,
+            'invoices' => [
+                [
+                    'invoice_id' => $this->invoice->hashed_id,
+                ],
+            ],
+            'credits' => [
+                [
+                    'credit_id' => $this->credit->hashed_id,
+                    'amount' => 5
+                ]
+            ],
+            'date' => '2019/12/12',
+        ];
+
+        $response = false;
+
+        try{
+            $response = $this->withHeaders([
+                'X-API-SECRET' => config('ninja.api_secret'),
+                'X-API-TOKEN' => $this->token,
+            ])->post('/api/v1/payments/', $data);
+        }catch(ValidationException $e){
+            $response->assertStatus(302);
+        }
+
+    }
+
+
+
+}
+