diff --git a/htdocs/fourn/class/api_supplier_invoices.class.php b/htdocs/fourn/class/api_supplier_invoices.class.php
index 09700c5885537..a09b8d4fbf6e8 100644
--- a/htdocs/fourn/class/api_supplier_invoices.class.php
+++ b/htdocs/fourn/class/api_supplier_invoices.class.php
@@ -18,8 +18,8 @@
 
 use Luracast\Restler\RestException;
 
-require_once DOL_DOCUMENT_ROOT.'/fourn/class/fournisseur.facture.class.php';
-require_once DOL_DOCUMENT_ROOT.'/fourn/class/paiementfourn.class.php';
+require_once DOL_DOCUMENT_ROOT . '/fourn/class/fournisseur.facture.class.php';
+require_once DOL_DOCUMENT_ROOT . '/fourn/class/paiementfourn.class.php';
 
 /**
  * API class for supplier invoices
@@ -75,7 +75,7 @@ public function get($id)
 		}
 
 		if (!DolibarrApi::_checkAccessToResource('fournisseur', $this->invoice->id, 'facture_fourn', 'facture')) {
-			throw new RestException(401, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+			throw new RestException(401, 'Access not allowed for login ' . DolibarrApiAccess::$user->login);
 		}
 
 		$this->invoice->fetchObjectLinked();
@@ -123,19 +123,19 @@ public function index($sortfield = "t.rowid", $sortorder = 'ASC', $limit = 100,
 		if (!DolibarrApiAccess::$user->hasRight("societe", "client", "voir") || $search_sale > 0) {
 			$sql .= ", sc.fk_soc, sc.fk_user";
 		}
-		$sql .= " FROM ".MAIN_DB_PREFIX."facture_fourn AS t LEFT JOIN ".MAIN_DB_PREFIX."facture_fourn_extrafields AS ef ON (ef.fk_object = t.rowid)"; // Modification VMR Global Solutions to include extrafields as search parameters in the API GET call, so we will be able to filter on extrafields
+		$sql .= " FROM " . MAIN_DB_PREFIX . "facture_fourn AS t LEFT JOIN " . MAIN_DB_PREFIX . "facture_fourn_extrafields AS ef ON (ef.fk_object = t.rowid)"; // Modification VMR Global Solutions to include extrafields as search parameters in the API GET call, so we will be able to filter on extrafields
 
 		// We need this table joined to the select in order to filter by sale
 		if (!DolibarrApiAccess::$user->hasRight("societe", "client", "voir") || $search_sale > 0) {
-			$sql .= ", ".MAIN_DB_PREFIX."societe_commerciaux as sc";
+			$sql .= ", " . MAIN_DB_PREFIX . "societe_commerciaux as sc";
 		}
 
-		$sql .= ' WHERE t.entity IN ('.getEntity('supplier_invoice').')';
+		$sql .= ' WHERE t.entity IN (' . getEntity('supplier_invoice') . ')';
 		if (!DolibarrApiAccess::$user->hasRight("societe", "client", "voir") || $search_sale > 0) {
 			$sql .= " AND t.fk_soc = sc.fk_soc";
 		}
 		if ($socids) {
-			$sql .= " AND t.fk_soc IN (".$this->db->sanitize($socids).")";
+			$sql .= " AND t.fk_soc IN (" . $this->db->sanitize($socids) . ")";
 		}
 		if ($search_sale > 0) {
 			$sql .= " AND t.rowid = sc.fk_soc"; // Join for the needed table to filter by sale
@@ -156,14 +156,14 @@ public function index($sortfield = "t.rowid", $sortorder = 'ASC', $limit = 100,
 		}
 		// Insert sale filter
 		if ($search_sale > 0) {
-			$sql .= " AND sc.fk_user = ".((int) $search_sale);
+			$sql .= " AND sc.fk_user = " . ((int) $search_sale);
 		}
 		// Add sql filters
 		if ($sqlfilters) {
 			$errormessage = '';
 			$sql .= forgeSQLFromUniversalSearchCriteria($sqlfilters, $errormessage);
 			if ($errormessage) {
-				throw new RestException(400, 'Error when validating parameter sqlfilters -> '.$errormessage);
+				throw new RestException(400, 'Error when validating parameter sqlfilters -> ' . $errormessage);
 			}
 		}
 
@@ -191,7 +191,7 @@ public function index($sortfield = "t.rowid", $sortorder = 'ASC', $limit = 100,
 				$i++;
 			}
 		} else {
-			throw new RestException(503, 'Error when retrieve supplier invoice list : '.$this->db->lasterror());
+			throw new RestException(503, 'Error when retrieve supplier invoice list : ' . $this->db->lasterror());
 		}
 		if (!count($obj_ret)) {
 			throw new RestException(404, 'No supplier invoice found');
@@ -257,7 +257,7 @@ public function put($id, $request_data = null)
 		}
 
 		if (!DolibarrApi::_checkAccessToResource('fournisseur', $this->invoice->id, 'facture_fourn', 'facture')) {
-			throw new RestException(401, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+			throw new RestException(401, 'Access not allowed for login ' . DolibarrApiAccess::$user->login);
 		}
 
 		foreach ($request_data as $field => $value) {
@@ -296,7 +296,7 @@ public function delete($id)
 		}
 
 		if (!DolibarrApi::_checkAccessToResource('fournisseur', $this->invoice->id, 'facture_fourn', 'facture')) {
-			throw new RestException(401, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+			throw new RestException(401, 'Access not allowed for login ' . DolibarrApiAccess::$user->login);
 		}
 
 		if ($this->invoice->delete(DolibarrApiAccess::$user) < 0) {
@@ -339,7 +339,7 @@ public function validate($id, $idwarehouse = 0, $notrigger = 0)
 		}
 
 		if (!DolibarrApi::_checkAccessToResource('fournisseur', $this->invoice->id, 'facture_fourn', 'facture')) {
-			throw new RestException(401, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+			throw new RestException(401, 'Access not allowed for login ' . DolibarrApiAccess::$user->login);
 		}
 
 		$result = $this->invoice->validate(DolibarrApiAccess::$user, '', $idwarehouse, $notrigger);
@@ -347,13 +347,13 @@ public function validate($id, $idwarehouse = 0, $notrigger = 0)
 			throw new RestException(304, 'Error nothing done. The invoice is already validated');
 		}
 		if ($result < 0) {
-			throw new RestException(500, 'Error when validating Invoice: '.$this->invoice->error);
+			throw new RestException(500, 'Error when validating Invoice: ' . $this->invoice->error);
 		}
 
 		return array(
 			'success' => array(
 				'code' => 200,
-				'message' => 'Invoice validated (Ref='.$this->invoice->ref.')'
+				'message' => 'Invoice validated (Ref=' . $this->invoice->ref . ')'
 			)
 		);
 	}
@@ -381,7 +381,7 @@ public function getPayments($id)
 		}
 
 		if (!DolibarrApi::_checkAccessToResource('fournisseur', $this->invoice->id, 'facture_fourn', 'facture')) {
-			throw new RestException(401, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+			throw new RestException(401, 'Access not allowed for login ' . DolibarrApiAccess::$user->login);
 		}
 
 		$result = $this->invoice->fetch($id);
@@ -410,6 +410,7 @@ public function getPayments($id)
 	 * @param string  $comment            {@from body}  Note (optional)
 	 * @param string  $chqemetteur        {@from body}  Payment issuer (mandatory if payment_mode_id corresponds to 'CHQ'-payment type)
 	 * @param string  $chqbank            {@from body}  Issuer bank name (optional)
+	 * @param float   $amount			  {@from body}  Amount of payment if we don't want to use the remain to pay
 	 *
 	 * @url     POST {id}/payments
 	 *
@@ -418,7 +419,7 @@ public function getPayments($id)
 	 * @throws RestException 401
 	 * @throws RestException 404
 	 */
-	public function addPayment($id, $datepaye, $payment_mode_id, $closepaidinvoices, $accountid, $num_payment = '', $comment = '', $chqemetteur = '', $chqbank = '')
+	public function addPayment($id, $datepaye, $payment_mode_id, $closepaidinvoices, $accountid, $num_payment = '', $comment = '', $chqemetteur = '', $chqbank = '', $amount = null)
 	{
 		global $conf;
 
@@ -430,7 +431,7 @@ public function addPayment($id, $datepaye, $payment_mode_id, $closepaidinvoices,
 		}
 
 		if (!DolibarrApi::_checkAccessToResource('fournisseur', $this->invoice->id, 'facture_fourn', 'facture')) {
-			throw new RestException(401, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+			throw new RestException(401, 'Access not allowed for login ' . DolibarrApiAccess::$user->login);
 		}
 
 		if (isModEnabled("banque")) {
@@ -449,18 +450,24 @@ public function addPayment($id, $datepaye, $payment_mode_id, $closepaidinvoices,
 			throw new RestException(404, 'Invoice not found');
 		}
 
-		// Calculate amount to pay
-		$totalpaid = $this->invoice->getSommePaiement();
-		$totaldeposits = $this->invoice->getSumDepositsUsed();
-		$resteapayer = price2num($this->invoice->total_ttc - $totalpaid - $totaldeposits, 'MT');
+		if (null !== $amount && $amount > 0) {
+			// We use the amount given in parameter
+			$paymentamount = $amount;
+		} else {
+			// We calculate the remain to pay, and use it as amount
+			$totalpaid = $this->invoice->getSommePaiement();
+			$totaldeposits = $this->invoice->getSumDepositsUsed();
+			$paymentamount = price2num($this->invoice->total_ttc - $totalpaid - $totaldeposits, 'MT');
+		}
 
 		$this->db->begin();
 
 		$amounts = array();
 		$multicurrency_amounts = array();
 
-		$resteapayer = price2num($resteapayer, 'MT');
-		$amounts[$id] = $resteapayer;
+		$paymentamount = price2num($paymentamount, 'MT');
+
+		$amounts[$id] = $paymentamount;
 
 		// Multicurrency
 		$newvalue = price2num($this->invoice->multicurrency_total_ttc, 'MT');
@@ -479,14 +486,14 @@ public function addPayment($id, $datepaye, $payment_mode_id, $closepaidinvoices,
 		$paiement_id = $paiement->create(DolibarrApiAccess::$user, ($closepaidinvoices == 'yes' ? 1 : 0)); // This include closing invoices
 		if ($paiement_id < 0) {
 			$this->db->rollback();
-			throw new RestException(400, 'Payment error : '.$paiement->error);
+			throw new RestException(400, 'Payment error : ' . $paiement->error);
 		}
 
 		if (isModEnabled("banque")) {
 			$result = $paiement->addPaymentToBank(DolibarrApiAccess::$user, 'payment_supplier', '(SupplierInvoicePayment)', $accountid, $chqemetteur, $chqbank);
 			if ($result < 0) {
 				$this->db->rollback();
-				throw new RestException(400, 'Add payment to bank error : '.$paiement->error);
+				throw new RestException(400, 'Add payment to bank error : ' . $paiement->error);
 			}
 		}
 
@@ -516,7 +523,7 @@ public function getLines($id)
 		}
 
 		if (!DolibarrApi::_checkAccessToResource('fournisseur', $this->invoice->id, 'facture_fourn', 'facture')) {
-			throw new RestException(401, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+			throw new RestException(401, 'Access not allowed for login ' . DolibarrApiAccess::$user->login);
 		}
 		$this->invoice->fetch_lines();
 		$result = array();
@@ -552,7 +559,7 @@ public function postLine($id, $request_data = null)
 		}
 
 		if (!DolibarrApi::_checkAccessToResource('fournisseur', $this->invoice->id, 'facture_fourn', 'facture')) {
-			throw new RestException(401, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+			throw new RestException(401, 'Access not allowed for login ' . DolibarrApiAccess::$user->login);
 		}
 
 		$request_data = (object) $request_data;
@@ -586,7 +593,7 @@ public function postLine($id, $request_data = null)
 		);
 
 		if ($updateRes < 0) {
-			throw new RestException(400, 'Unable to insert the new line. Check your inputs. '.$this->invoice->error);
+			throw new RestException(400, 'Unable to insert the new line. Check your inputs. ' . $this->invoice->error);
 		}
 
 		return $updateRes;
@@ -619,7 +626,7 @@ public function putLine($id, $lineid, $request_data = null)
 		}
 
 		if (!DolibarrApi::_checkAccessToResource('fournisseur', $this->invoice->id, 'facture_fourn', 'facture')) {
-			throw new RestException(401, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+			throw new RestException(401, 'Access not allowed for login ' . DolibarrApiAccess::$user->login);
 		}
 
 		$request_data = (object) $request_data;
@@ -690,7 +697,7 @@ public function deleteLine($id, $lineid)
 		}
 
 		if (!DolibarrApi::_checkAccessToResource('fournisseur', $this->invoice->id, 'facture_fourn', 'facture')) {
-			throw new RestException(401, 'Access not allowed for login '.DolibarrApiAccess::$user->login);
+			throw new RestException(401, 'Access not allowed for login ' . DolibarrApiAccess::$user->login);
 		}
 
 		// TODO Check the lineid $lineid is a line of ojbect