diff --git a/htdocs/compta/facture/class/api_invoices.class.php b/htdocs/compta/facture/class/api_invoices.class.php
index 8d6eb7a46f2..e79ef595a41 100644
--- a/htdocs/compta/facture/class/api_invoices.class.php
+++ b/htdocs/compta/facture/class/api_invoices.class.php
@@ -4,6 +4,7 @@
  * Copyright (C) 2023		Joachim Kueter			<git-jk@bloxera.com>
  * Copyright (C) 2024-2025  Frédéric France			<frederic.france@free.fr>
  * Copyright (C) 2024-2025	MDW						<mdeweerd@users.noreply.github.com>
+ * Copyright (C) 2025		Charlene Benke			<charlene@patas-monkey.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -621,6 +622,42 @@ class Invoices extends DolibarrApi
 		);
 	}
 
+	/**
+	 * Get contacts of given invoice
+	 *
+	 * Return an array with contact information
+	 *
+	 * @param	int					$id			ID of invoice
+	 * @param	string				$type		Type of the contact (BILLING, SHIPPING, CUSTOMER)
+	 * @return	array<int,mixed>				Array with contact and user associated
+	 *
+	 * @url	GET {id}/contacts
+	 *
+	 * @throws	RestException
+	 */
+	public function getContacts($id, $type = '')
+	{
+		if (!DolibarrApiAccess::$user->hasRight('facture', 'lire')) {
+			throw new RestException(403);
+		}
+
+		$result = $this->invoice->fetch($id);
+		if (!$result) {
+			throw new RestException(404, 'Invoice not found');
+		}
+
+		if (!DolibarrApi::_checkAccessToResource('facture', $this->invoice->id)) {
+			throw new RestException(403, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+		}
+
+		$contacts = $this->invoice->liste_contact(-1, 'external', 0, $type);
+		$socpeoples = $this->invoice->liste_contact(-1, 'internal', 0, $type);
+
+		$contacts = array_merge($contacts, $socpeoples);
+
+		return $contacts;
+	}
+
 	/**
 	 * Delete a contact type of given invoice
 	 *