diff --git a/src/main/java/alfio/manager/EuVatChecker.java b/src/main/java/alfio/manager/EuVatChecker.java
index 575c6160e4..984355dd33 100644
--- a/src/main/java/alfio/manager/EuVatChecker.java
+++ b/src/main/java/alfio/manager/EuVatChecker.java
@@ -36,13 +36,17 @@
 import org.springframework.stereotype.Component;
 
 import java.io.IOException;
-import java.util.*;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BiFunction;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
 import static alfio.model.Audit.EntityType.RESERVATION;
+import static alfio.model.Audit.EventType.VAT_FORMAL_VALIDATION_SUCCESSFUL;
 import static alfio.model.Audit.EventType.VAT_VALIDATION_SUCCESSFUL;
 import static alfio.model.system.Configuration.getSystemConfiguration;
 import static alfio.model.system.ConfigurationKeys.APPLY_VAT_FOREIGN_BUSINESS;
@@ -55,6 +59,7 @@ public class EuVatChecker {
 
     private final ConfigurationManager configurationManager;
     private final AuditingRepository auditingRepository;
+    private final ExtensionManager extensionManager;
     private final OkHttpClient client = new OkHttpClient();
 
     private static final Cache<Pair<String, String>, Map<String, String>> validationCache = Caffeine.newBuilder()
@@ -167,12 +172,18 @@ public boolean test(String vatNr) {
             }
 
             Map<String, String> result = validateEUVat(vatNr, organizerCountry, checker.configurationManager, checker.client);
-            boolean valid = result != null && isValid(result);
+            boolean validStrict = result != null && isValid(result);
+            boolean valid = validStrict;
+
+            if(!valid && StringUtils.isNotBlank(vatNr)) {
+                valid = checker.extensionManager.handleTaxIdValidation(eventId, vatNr, organizerCountry);
+            }
+
             if(valid && StringUtils.isNotEmpty(ticketReservationId)) {
                 Map<String, Object> data = new HashMap<>();
                 data.put("vatNumber", vatNr);
                 data.put("country", organizerCountry);
-                checker.auditingRepository.insert(ticketReservationId, null, eventId, VAT_VALIDATION_SUCCESSFUL, new Date(), RESERVATION, ticketReservationId, singletonList(data));
+                checker.auditingRepository.insert(ticketReservationId, null, eventId, validStrict ? VAT_VALIDATION_SUCCESSFUL : VAT_FORMAL_VALIDATION_SUCCESSFUL, new Date(), RESERVATION, ticketReservationId, singletonList(data));
             }
             return valid;
         }
diff --git a/src/main/java/alfio/manager/ExtensionManager.java b/src/main/java/alfio/manager/ExtensionManager.java
index 6c055ebb73..736d3e315f 100644
--- a/src/main/java/alfio/manager/ExtensionManager.java
+++ b/src/main/java/alfio/manager/ExtensionManager.java
@@ -43,6 +43,7 @@ public enum ExtensionEvent {
         TICKET_ASSIGNED,
         WAITING_QUEUE_SUBSCRIBED,
         INVOICE_GENERATION,
+        TAX_ID_NUMBER_VALIDATION,
         //
         STUCK_RESERVATIONS,
         OFFLINE_RESERVATIONS_WILL_EXPIRE,
@@ -155,6 +156,14 @@ public Optional<InvoiceGeneration> handleInvoiceGeneration(Event event, String r
         return Optional.ofNullable(syncCall(ExtensionEvent.INVOICE_GENERATION, event, event.getOrganizationId(), payload, InvoiceGeneration.class));
     }
 
+    public boolean handleTaxIdValidation(int eventId, String taxIdNumber, String countryCode) {
+        Event event = eventRepository.findById(eventId);
+        Map<String, Object> payload = new HashMap<>();
+        payload.put("taxIdNumber", taxIdNumber);
+        payload.put("countryCode", countryCode);
+        return Optional.ofNullable(syncCall(ExtensionEvent.TAX_ID_NUMBER_VALIDATION, event, event.getOrganizationId(), payload, Boolean.class)).orElse(false);
+    }
+
     public void handleTicketCheckedIn(Ticket ticket) {
         Map<String, Object> payload = new HashMap<>();
         Event event = eventRepository.findById(ticket.getEventId());
diff --git a/src/main/java/alfio/model/Audit.java b/src/main/java/alfio/model/Audit.java
index 7bf6ee18df..8fd7d4efd1 100644
--- a/src/main/java/alfio/model/Audit.java
+++ b/src/main/java/alfio/model/Audit.java
@@ -50,7 +50,8 @@ public enum EventType {
         FORCED_UPDATE_INVOICE,
         TERMS_CONDITION_ACCEPTED,
         PRIVACY_POLICY_ACCEPTED,
-        VAT_VALIDATION_SUCCESSFUL
+        VAT_VALIDATION_SUCCESSFUL,
+        VAT_FORMAL_VALIDATION_SUCCESSFUL
     }
 
     private final String reservationId;