diff --git a/Koha/REST/V1/Checkouts.pm b/Koha/REST/V1/Checkouts.pm
index 301369a45c..a2c76c6efa 100644
--- a/Koha/REST/V1/Checkouts.pm
+++ b/Koha/REST/V1/Checkouts.pm
@@ -189,6 +189,7 @@ sub add {
     my $item_id   = $body->{item_id};
     my $patron_id = $body->{patron_id};
     my $onsite    = $body->{onsite_checkout};
+    my $barcode   = $body->{external_id};
 
     if ( $c->stash('is_public')
         && !C4::Context->preference('OpacTrustedCheckout') )
@@ -203,7 +204,24 @@ sub add {
     }
 
     return try {
-        my $item = Koha::Items->find($item_id);
+
+        unless ( $item_id or $barcode ) {
+            return $c->render(
+                status  => 400,
+                openapi => {
+                    error      => 'Missing or wrong parameters',
+                    error_code => 'MISSING_OR_WRONG_PARAMETERS',
+                }
+            );
+        }
+
+        my $item;
+        if ($item_id) {
+            $item = Koha::Items->find($item_id);
+        } else {
+            $item = Koha::Items->find( { barcode => $barcode } );
+        }
+
         unless ($item) {
             return $c->render(
                 status  => 409,
@@ -214,6 +232,21 @@ sub add {
             );
         }
 
+        # check that item matches when barcode and item_id were given
+        if (    $item_id
+            and $barcode
+            and ( $item->barcode ne $barcode or $item->id != $item_id ) )
+        {
+            return $c->render(
+                status  => 409,
+                openapi => {
+                    error      => 'Item id and external id belong to different items',
+                    error_code => 'ITEM_ID_NOT_MATCHING_EXTERNAL_ID',
+                }
+            );
+        }
+
+
         my $patron = Koha::Patrons->find($patron_id);
         unless ($patron) {
             return $c->render(
diff --git a/api/v1/swagger/definitions/checkout.yaml b/api/v1/swagger/definitions/checkout.yaml
index 4a9847623c..4ace091bd5 100644
--- a/api/v1/swagger/definitions/checkout.yaml
+++ b/api/v1/swagger/definitions/checkout.yaml
@@ -11,7 +11,11 @@ properties:
     type:
       - integer
       - "null"
-    description: internal identifier of checked out item
+  external_id:
+    type:
+      - string
+      - "null"
+    description: other identifier of checked out item f.e. barcode
   due_date:
     type: string
     format: date-time
diff --git a/t/db_dependent/api/v1/checkouts.t b/t/db_dependent/api/v1/checkouts.t
index 8f306df0e0..779f00156a 100755
--- a/t/db_dependent/api/v1/checkouts.t
+++ b/t/db_dependent/api/v1/checkouts.t
@@ -439,7 +439,7 @@ subtest 'get_availability' => sub {
 
 subtest 'add checkout' => sub {
 
-    plan tests => 10;
+    plan tests => 14;
 
     $schema->storage->txn_begin;
     my $librarian = $builder->build_object(
@@ -465,8 +465,13 @@ subtest 'add checkout' => sub {
 
     my $branchcode = $builder->build( { source => 'Branch' } )->{branchcode};
 
-    my $item1    = $builder->build_sample_item;
-    my $item1_id = $item1->id;
+    my $item1         = $builder->build_sample_item;
+    my $item1_id      = $item1->id;
+    my $item1_barcode = $item1->barcode;
+
+    my $item2         = $builder->build_sample_item;
+    my $item2_id      = $item2->id;
+    my $item2_barcode = $item2->barcode;
 
     my %issuingimpossible = ();
     my %needsconfirmation = ();
@@ -491,6 +496,19 @@ subtest 'add checkout' => sub {
     $t->post_ok( "//$userid:$password@/api/v1/checkouts" => json => { item_id => $item1_id, patron_id => $patron_id } )
         ->status_is(201);
 
+    $t->post_ok(
+        "//$userid:$password@/api/v1/checkouts" => json => { external_id => $item1_barcode, patron_id => $patron_id } )
+        ->status_is(201);
+
+    # mismatch of item_id and barcode when both given
+    $t->post_ok(
+        "//$userid:$password@/api/v1/checkouts" => json => {
+            external_id => $item1_barcode,
+            item_id     => $item2_id,
+            patron_id   => $patron_id
+        }
+    )->status_is(409);
+
     # Needs confirm
     %needsconfirmation = ( confirm1 => 1, confirm2 => 'please' );
     $t->post_ok(