diff --git a/VALIDATION-ERROR-FIX.md b/VALIDATION-ERROR-FIX.md
new file mode 100644
index 0000000..db12d27
--- /dev/null
+++ b/VALIDATION-ERROR-FIX.md
@@ -0,0 +1,106 @@
+# Fix Urgent - Erreurs de Validation Zod
+
+## ❌ Problème Identifié
+**Erreur 500 :** ZodError lors de PUT /api/deliveries/:id
+
+### Erreurs Specifiques
+1. **blAmount** : Expected string, received number
+2. **validatedAt** : Expected date, received string
+
+## 🔍 Analyse du Problème
+
+### Schema Drizzle (shared/schema.ts)
+```typescript
+// Dans deliveries table:
+blAmount: decimal("bl_amount", { precision: 10, scale: 2 })      // → Zod attend string
+invoiceAmount: decimal("invoice_amount", { precision: 10, scale: 2 }) // → Zod attend string
+validatedAt: timestamp("validated_at")                           // → Zod attend Date object
+```
+
+### Données Envoyées depuis Frontend
+```javascript
+// ❌ Problématique
+{
+  blAmount: 3397.86,                    // number → should be string
+  invoiceAmount: null,                  // OK
+  validatedAt: '2025-08-12T11:42:39.679Z' // string → should be Date
+}
+```
+
+## ✅ Solutions Appliquées
+
+### 1. **Transformation côté Serveur** (server/routes.ts)
+```typescript
+// Avant validation Zod, transformer les types
+const transformedData = { ...req.body };
+
+// Convertir montants number → string
+if (transformedData.blAmount !== undefined && transformedData.blAmount !== null) {
+  transformedData.blAmount = transformedData.blAmount.toString();
+}
+if (transformedData.invoiceAmount !== undefined && transformedData.invoiceAmount !== null) {
+  transformedData.invoiceAmount = transformedData.invoiceAmount.toString();
+}
+
+// Convertir validatedAt string → Date
+if (transformedData.validatedAt && typeof transformedData.validatedAt === 'string') {
+  transformedData.validatedAt = new Date(transformedData.validatedAt);
+}
+
+const data = insertDeliverySchema.partial().parse(transformedData);
+```
+
+### 2. **Correction côté Frontend** (ReconciliationModal.tsx)
+```typescript
+// Avant
+validatedAt: new Date()              // ❌ Date object → string lors JSON.stringify
+
+// Après  
+validatedAt: new Date().toISOString() // ✅ string → convertie en Date côté serveur
+```
+
+### 3. **Montants toujours en string** (ReconciliationModal.tsx)
+```typescript
+// Déjà corrigé précédemment
+blAmount: formData.blAmount ? formData.blAmount.toString() : null,
+invoiceAmount: formData.invoiceAmount ? formData.invoiceAmount.toString() : null,
+```
+
+## 🧪 Test de Validation
+
+### Payload Attendu Maintenant
+```javascript
+// ✅ Correct après transformation
+{
+  blNumber: 'LD2250800571',
+  blAmount: '3397.86',                   // string ✅
+  invoiceReference: null,
+  invoiceAmount: null,
+  reconciled: true,
+  validatedAt: new Date('2025-08-12T11:42:39.679Z') // Date object ✅
+}
+```
+
+### Tests à Effectuer
+1. **Enregistrer données BL** : blAmount doit passer en string
+2. **Valider rapprochement** : validatedAt doit passer en Date
+3. **Enregistrer montant facture** : invoiceAmount doit passer en string
+4. **Vérifier console** : Plus d'erreurs ZodError 500
+
+## 🔄 Flux de Données Complet
+
+```
+Frontend Form → JSON.stringify → HTTP Request → Server Transform → Zod Validation → Database
+     ↓              ↓                ↓               ↓               ↓             ↓
+{number}     →  "3397.86"    →    "3397.86"   →    "3397.86"   →    ✅         →  DECIMAL
+{Date}       →  "2025-..."   →    "2025-..."  →    Date(...)   →    ✅         →  TIMESTAMP
+```
+
+## 📊 Status
+
+- ✅ Transformation automatique côté serveur
+- ✅ Frontend envoie validatedAt en ISO string  
+- ✅ Montants forcés en string côté client
+- 🔄 **À tester en production**
+
+**L'erreur 500 ZodError devrait être résolue !**
\ No newline at end of file
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diff --git a/client/src/components/modals/ReconciliationModal.tsx b/client/src/components/modals/ReconciliationModal.tsx
index 702138e..0ee5fbf 100644
--- a/client/src/components/modals/ReconciliationModal.tsx
+++ b/client/src/components/modals/ReconciliationModal.tsx
@@ -90,9 +90,9 @@ export default function ReconciliationModal({
 
     updateDeliveryMutation.mutate({
       blNumber: formData.blNumber.trim(),
-      blAmount: formData.blAmount ? parseFloat(formData.blAmount) : null,
+      blAmount: formData.blAmount ? formData.blAmount.toString() : null,
       invoiceReference: formData.invoiceReference.trim() || null,
-      invoiceAmount: formData.invoiceAmount ? parseFloat(formData.invoiceAmount) : null,
+      invoiceAmount: formData.invoiceAmount ? formData.invoiceAmount.toString() : null,
     });
   };
 
@@ -108,9 +108,9 @@ export default function ReconciliationModal({
 
     updateDeliveryMutation.mutate({
       blNumber: formData.blNumber.trim(),
-      blAmount: formData.blAmount ? parseFloat(formData.blAmount) : null,
+      blAmount: formData.blAmount ? formData.blAmount.toString() : null,
       invoiceReference: formData.invoiceReference.trim() || null,
-      invoiceAmount: formData.invoiceAmount ? parseFloat(formData.invoiceAmount) : null,
+      invoiceAmount: formData.invoiceAmount ? formData.invoiceAmount.toString() : null,
       reconciled: true,
       validatedAt: new Date().toISOString()
     });
diff --git a/server/routes.ts b/server/routes.ts
index dc7414f..c2667cb 100644
--- a/server/routes.ts
+++ b/server/routes.ts
@@ -690,7 +690,24 @@ export async function registerRoutes(app: Express): Promise<Server> {
       }
 
       console.log('🔄 Updating delivery:', { id, data: req.body, user: user.id });
-      const data = insertDeliverySchema.partial().parse(req.body);
+      
+      // Transform data types before validation
+      const transformedData = { ...req.body };
+      
+      // Convert decimal amounts to strings (schema expects string for decimal fields)
+      if (transformedData.blAmount !== undefined && transformedData.blAmount !== null) {
+        transformedData.blAmount = transformedData.blAmount.toString();
+      }
+      if (transformedData.invoiceAmount !== undefined && transformedData.invoiceAmount !== null) {
+        transformedData.invoiceAmount = transformedData.invoiceAmount.toString();
+      }
+      
+      // Convert validatedAt to Date object (schema expects Date for timestamp fields)
+      if (transformedData.validatedAt && typeof transformedData.validatedAt === 'string') {
+        transformedData.validatedAt = new Date(transformedData.validatedAt);
+      }
+      
+      const data = insertDeliverySchema.partial().parse(transformedData);
       const updatedDelivery = await storage.updateDelivery(id, data);
       console.log('✅ Delivery updated successfully:', { id, updatedDelivery });
       
@@ -721,7 +738,7 @@ export async function registerRoutes(app: Express): Promise<Server> {
             // Auto-valider le rapprochement
             await storage.updateDelivery(id, {
               reconciled: true,
-              validatedAt: new Date()
+              validatedAt: new Date().toISOString()
             });
             
             console.log(`✅ Auto-reconciliation: Delivery #${id} automatically validated for supplier ${supplier.name}`);