diff --git a/app/components/messages/MessageInput.vue b/app/components/messages/MessageInput.vue
index 0ea253e..08199fa 100644
--- a/app/components/messages/MessageInput.vue
+++ b/app/components/messages/MessageInput.vue
@@ -184,6 +184,16 @@ const caption = ref('')
 const isDragging = ref(false)
 const stickerModes = ref<boolean[]>([])
 
+// File size limits (in bytes) - should match server
+const MAX_SIZES: Record<string, number> = {
+  image: 16 * 1024 * 1024,      // 16 MB
+  video: 64 * 1024 * 1024,      // 64 MB
+  audio: 16 * 1024 * 1024,      // 16 MB
+  document: 100 * 1024 * 1024,  // 100 MB
+}
+
+const toast = useToast()
+
 // Audio recorder
 const {
   isRecording,
@@ -242,12 +252,48 @@ const handleFileSelect = (event: Event, type: string) => {
   }
 }
 
+const getFileMediaType = (file: File): string => {
+  if (file.type.startsWith('image/')) return 'image'
+  if (file.type.startsWith('video/')) return 'video'
+  if (file.type.startsWith('audio/')) return 'audio'
+  return 'document'
+}
+
+const formatFileSize = (bytes: number): string => {
+  if (bytes === 0) return '0 B'
+  const k = 1024
+  const sizes = ['B', 'KB', 'MB', 'GB']
+  const i = Math.floor(Math.log(bytes) / Math.log(k))
+  return `${parseFloat((bytes / Math.pow(k, i)).toFixed(1))} ${sizes[i]}`
+}
+
 const addFiles = (files: File[]) => {
   // Limit to 10 files
   const remaining = 10 - selectedFiles.value.length
   const toAdd = files.slice(0, remaining)
-  // Use spread operator to trigger reactivity
-  selectedFiles.value = [...selectedFiles.value, ...toAdd]
+
+  // Validate file sizes
+  const validFiles: File[] = []
+  for (const file of toAdd) {
+    const mediaType = getFileMediaType(file)
+    const maxSize = MAX_SIZES[mediaType]
+
+    if (file.size > maxSize) {
+      toast.add({
+        title: 'Archivo muy grande',
+        description: `${file.name} (${formatFileSize(file.size)}) excede el límite de ${formatFileSize(maxSize)} para ${mediaType}`,
+        color: 'error',
+        duration: 5000
+      })
+    } else {
+      validFiles.push(file)
+    }
+  }
+
+  if (validFiles.length > 0) {
+    // Use spread operator to trigger reactivity
+    selectedFiles.value = [...selectedFiles.value, ...validFiles]
+  }
 }
 
 const handleDrop = (event: DragEvent) => {
diff --git a/app/pages/messages/index.vue b/app/pages/messages/index.vue
index ff1c552..600580e 100644
--- a/app/pages/messages/index.vue
+++ b/app/pages/messages/index.vue
@@ -548,8 +548,23 @@ const handleSendMessage = async (content: string, files: File[], caption: string
 
     // Reload messages
     messages.value = await $fetch(`/api/messages/${instanceId}/${chatId}`)
-  } catch (e) {
+  } catch (e: any) {
     console.error('Error sending message:', e)
+
+    // Extract error message from response
+    let errorMessage = 'Error al enviar el mensaje'
+    if (e?.data?.message) {
+      errorMessage = e.data.message
+    } else if (e?.message) {
+      errorMessage = e.message
+    }
+
+    toast.add({
+      title: 'Error de envío',
+      description: errorMessage,
+      color: 'error',
+      duration: 5000
+    })
   }
 }