diff --git a/app/components/machine/MachineCustomFieldDefEditor.vue b/app/components/machine/MachineCustomFieldDefEditor.vue
new file mode 100644
index 0000000..98eccad
--- /dev/null
+++ b/app/components/machine/MachineCustomFieldDefEditor.vue
@@ -0,0 +1,124 @@
+<template>
+  <section class="space-y-3">
+    <div class="flex items-center justify-between">
+      <h3 class="text-sm font-semibold">
+        Définitions des champs personnalisés
+      </h3>
+      <button
+        type="button"
+        class="btn btn-primary btn-sm"
+        :disabled="saving"
+        @click="$emit('save')"
+      >
+        <span v-if="saving" class="loading loading-spinner loading-xs" />
+        Enregistrer les champs
+      </button>
+    </div>
+
+    <p v-if="!fields.length" class="text-xs text-gray-500">
+      Aucun champ personnalisé défini. Cliquez sur « Ajouter » pour en créer un.
+    </p>
+
+    <ul v-else class="space-y-2" role="list">
+      <li
+        v-for="(field, index) in fields"
+        :key="field.uid"
+        class="border border-base-200 rounded-md p-3 space-y-2 bg-base-100 transition-colors"
+        :class="reorderClass(index)"
+        draggable="true"
+        @dragstart="onDragStart(index, $event)"
+        @dragenter="onDragEnter(index)"
+        @dragover.prevent="onDragEnter(index)"
+        @drop.prevent="onDrop(index)"
+        @dragend="onDragEnd"
+      >
+        <div class="flex items-start gap-3">
+          <button
+            type="button"
+            class="btn btn-ghost btn-xs btn-square cursor-grab active:cursor-grabbing mt-1"
+            title="Réordonner"
+            draggable="false"
+          >
+            <IconLucideGripVertical class="w-4 h-4" aria-hidden="true" />
+          </button>
+
+          <div class="flex-1 space-y-2">
+            <div class="grid grid-cols-1 md:grid-cols-2 gap-2">
+              <input
+                v-model="field.name"
+                type="text"
+                class="input input-bordered input-sm"
+                placeholder="Nom du champ"
+              >
+              <select v-model="field.type" class="select select-bordered select-sm">
+                <option value="text">
+                  Texte
+                </option>
+                <option value="number">
+                  Nombre
+                </option>
+                <option value="select">
+                  Liste
+                </option>
+                <option value="boolean">
+                  Oui/Non
+                </option>
+                <option value="date">
+                  Date
+                </option>
+              </select>
+            </div>
+
+            <div class="flex items-center gap-2 text-xs">
+              <input v-model="field.required" type="checkbox" class="checkbox checkbox-xs">
+              Obligatoire
+            </div>
+
+            <textarea
+              v-if="field.type === 'select'"
+              v-model="field.optionsText"
+              class="textarea textarea-bordered textarea-sm h-20"
+              placeholder="Option 1&#10;Option 2"
+            />
+          </div>
+
+          <button
+            type="button"
+            class="btn btn-error btn-xs btn-square"
+            @click="$emit('remove-field', index)"
+          >
+            <IconLucideTrash class="w-4 h-4" aria-hidden="true" />
+          </button>
+        </div>
+      </li>
+    </ul>
+
+    <button type="button" class="btn btn-outline btn-sm" @click="$emit('add-field')">
+      <IconLucidePlus class="w-3 h-3 mr-2" aria-hidden="true" />
+      Ajouter un champ
+    </button>
+  </section>
+</template>
+
+<script setup lang="ts">
+import type { MachineCustomFieldEditorField } from '~/composables/useMachineCustomFieldDefs'
+import IconLucideGripVertical from '~icons/lucide/grip-vertical'
+import IconLucidePlus from '~icons/lucide/plus'
+import IconLucideTrash from '~icons/lucide/trash'
+
+defineProps<{
+  fields: MachineCustomFieldEditorField[]
+  saving: boolean
+  reorderClass: (index: number) => string
+  onDragStart: (index: number, event: DragEvent) => void
+  onDragEnter: (index: number) => void
+  onDrop: (index: number) => void
+  onDragEnd: () => void
+}>()
+
+defineEmits<{
+  save: []
+  'add-field': []
+  'remove-field': [index: number]
+}>()
+</script>
diff --git a/app/components/machine/MachineInfoCard.vue b/app/components/machine/MachineInfoCard.vue
index 8606bc8..d9fd55d 100644
--- a/app/components/machine/MachineInfoCard.vue
+++ b/app/components/machine/MachineInfoCard.vue
@@ -151,18 +151,36 @@
           </div>
         </div>
       </div>
+
+      <div v-if="isEditMode" class="mt-6 pt-4 border-t border-base-200">
+        <MachineCustomFieldDefEditor
+          :fields="fieldDefs.fields.value"
+          :saving="fieldDefs.saving.value"
+          :reorder-class="fieldDefs.reorderClass"
+          :on-drag-start="fieldDefs.onDragStart"
+          :on-drag-enter="fieldDefs.onDragEnter"
+          :on-drop="fieldDefs.onDrop"
+          :on-drag-end="fieldDefs.onDragEnd"
+          @save="fieldDefs.saveDefinitions()"
+          @add-field="fieldDefs.addField()"
+          @remove-field="fieldDefs.removeField($event)"
+        />
+      </div>
     </div>
   </div>
 </template>
 
 <script setup lang="ts">
+import { watch } from 'vue'
 import ConstructeurSelect from '~/components/ConstructeurSelect.vue'
+import MachineCustomFieldDefEditor from '~/components/machine/MachineCustomFieldDefEditor.vue'
 import {
   formatConstructeurContact as formatConstructeurContactSummary,
 } from '~/shared/constructeurUtils'
 import { formatCustomFieldValue } from '~/shared/utils/customFieldUtils'
+import { useMachineCustomFieldDefs } from '~/composables/useMachineCustomFieldDefs'
 
-defineProps<{
+const props = defineProps<{
   isEditMode: boolean
   machineName: string
   machineReference: string
@@ -171,14 +189,27 @@ defineProps<{
   hasMachineConstructeur: boolean
   visibleCustomFields: any[]
   getMachineFieldId: (fieldName: string) => string
+  machineId: string
+  machineCustomFieldDefs: any[]
 }>()
 
-defineEmits<{
+const emit = defineEmits<{
   'update:machine-name': [value: string]
   'update:machine-reference': [value: string]
   'update:constructeur-ids': [ids: unknown]
   'blur-field': []
   'set-custom-field-value': [field: any, value: unknown]
   'update-custom-field': [field: any]
+  'custom-fields-saved': []
 }>()
+
+const fieldDefs = useMachineCustomFieldDefs({
+  machineId: props.machineId,
+  initialDefs: props.machineCustomFieldDefs,
+  onSaved: () => emit('custom-fields-saved'),
+})
+
+watch(() => props.machineCustomFieldDefs, (newDefs) => {
+  fieldDefs.reinit(newDefs)
+}, { deep: true })
 </script>
diff --git a/app/composables/useMachineCustomFieldDefs.ts b/app/composables/useMachineCustomFieldDefs.ts
new file mode 100644
index 0000000..a4e9a94
--- /dev/null
+++ b/app/composables/useMachineCustomFieldDefs.ts
@@ -0,0 +1,327 @@
+import { reactive, ref } from 'vue'
+import { useApi } from '~/composables/useApi'
+import { useToast } from '~/composables/useToast'
+
+// --- Types ---
+
+export type MachineFieldType = 'text' | 'number' | 'select' | 'boolean' | 'date'
+
+export interface MachineCustomFieldEditorField {
+  uid: string
+  serverId?: string
+  name: string
+  type: MachineFieldType
+  required: boolean
+  optionsText: string
+  orderIndex: number
+}
+
+interface InitialDef {
+  id: string
+  name: string
+  type: string
+  required: boolean
+  options?: string[]
+  orderIndex: number
+  defaultValue?: unknown
+}
+
+interface Deps {
+  machineId: string
+  initialDefs: InitialDef[]
+  onSaved: () => void | Promise<void>
+}
+
+// --- Helpers ---
+
+let uidCounter = 0
+const createUid = (): string => {
+  if (typeof crypto !== 'undefined' && typeof crypto.randomUUID === 'function') {
+    return crypto.randomUUID()
+  }
+  uidCounter += 1
+  return `mcf-${Date.now().toString(36)}-${uidCounter}`
+}
+
+const normalizeLineEndings = (value: string): string =>
+  value.replace(/\r\n/g, '\n').replace(/\r/g, '\n')
+
+const toEditorField = (def: InitialDef, index: number): MachineCustomFieldEditorField => ({
+  uid: createUid(),
+  serverId: def.id,
+  name: def.name || '',
+  type: (def.type || 'text') as MachineFieldType,
+  required: Boolean(def.required),
+  optionsText: normalizeLineEndings(
+    Array.isArray(def.options) ? def.options.join('\n') : '',
+  ),
+  orderIndex: typeof def.orderIndex === 'number' ? def.orderIndex : index,
+})
+
+const hydrateFields = (defs: InitialDef[]): MachineCustomFieldEditorField[] =>
+  defs
+    .map((def, index) => toEditorField(def, index))
+    .sort((a, b) => a.orderIndex - b.orderIndex)
+    .map((field, index) => ({ ...field, orderIndex: index }))
+
+const buildSnapshot = (defs: InitialDef[]): Map<string, InitialDef> => {
+  const map = new Map<string, InitialDef>()
+  for (const def of defs) {
+    map.set(def.id, def)
+  }
+  return map
+}
+
+const applyOrderIndex = (
+  list: MachineCustomFieldEditorField[],
+): MachineCustomFieldEditorField[] =>
+  list.map((field, index) => ({ ...field, orderIndex: index }))
+
+const parseOptions = (optionsText: string): string[] =>
+  normalizeLineEndings(optionsText)
+    .split('\n')
+    .map(o => o.trim())
+    .filter(o => o.length > 0)
+
+// --- Composable ---
+
+export function useMachineCustomFieldDefs(deps: Deps) {
+  const { apiCall } = useApi()
+  const { showSuccess, showError } = useToast()
+
+  // --- State ---
+
+  const fields = ref<MachineCustomFieldEditorField[]>(hydrateFields(deps.initialDefs))
+  const initialSnapshot = ref<Map<string, InitialDef>>(buildSnapshot(deps.initialDefs))
+  const saving = ref(false)
+
+  // --- CRUD ---
+
+  const addField = () => {
+    const next = fields.value.slice()
+    next.push({
+      uid: createUid(),
+      name: '',
+      type: 'text',
+      required: false,
+      optionsText: '',
+      orderIndex: next.length,
+    })
+    fields.value = applyOrderIndex(next)
+  }
+
+  const removeField = (index: number) => {
+    const next = fields.value.filter((_, i) => i !== index)
+    fields.value = applyOrderIndex(next)
+  }
+
+  // --- Drag & drop ---
+
+  const dragState = reactive({
+    draggingIndex: null as number | null,
+    dropTargetIndex: null as number | null,
+  })
+
+  const resetDragState = () => {
+    dragState.draggingIndex = null
+    dragState.dropTargetIndex = null
+  }
+
+  const onDragStart = (index: number, event: DragEvent) => {
+    dragState.draggingIndex = index
+    dragState.dropTargetIndex = index
+    if (event.dataTransfer) {
+      event.dataTransfer.effectAllowed = 'move'
+    }
+  }
+
+  const onDragEnter = (index: number) => {
+    if (dragState.draggingIndex === null) return
+    dragState.dropTargetIndex = index
+  }
+
+  const onDrop = (index: number) => {
+    const from = dragState.draggingIndex
+    if (from === null) {
+      resetDragState()
+      return
+    }
+
+    if (from === index) {
+      resetDragState()
+      return
+    }
+
+    const list = fields.value.slice()
+    if (from < 0 || index < 0 || from >= list.length || index >= list.length) {
+      resetDragState()
+      return
+    }
+
+    const [moved] = list.splice(from, 1)
+    if (!moved) {
+      resetDragState()
+      return
+    }
+    list.splice(index, 0, moved)
+    fields.value = applyOrderIndex(list)
+    resetDragState()
+  }
+
+  const onDragEnd = () => {
+    resetDragState()
+  }
+
+  const reorderClass = (index: number): string => {
+    if (dragState.draggingIndex === index) {
+      return 'border-dashed border-primary bg-primary/5'
+    }
+    if (
+      dragState.draggingIndex !== null
+      && dragState.dropTargetIndex === index
+      && dragState.draggingIndex !== index
+    ) {
+      return 'border-primary border-dashed bg-primary/10'
+    }
+    return ''
+  }
+
+  // --- Save ---
+
+  const saveDefinitions = async () => {
+    if (saving.value) return
+
+    // Validate: remove empty-name fields before saving
+    const emptyNameFields = fields.value.filter(f => !f.name.trim() && !f.serverId)
+    if (emptyNameFields.length > 0) {
+      fields.value = applyOrderIndex(fields.value.filter(f => f.name.trim() || f.serverId))
+    }
+
+    saving.value = true
+
+    try {
+      const snapshot = initialSnapshot.value
+      const currentServerIds = new Set(
+        fields.value.filter(f => f.serverId).map(f => f.serverId!),
+      )
+
+      // DELETE removed fields
+      const deletedIds = [...snapshot.keys()].filter(id => !currentServerIds.has(id))
+      for (const id of deletedIds) {
+        const result = await apiCall(`/custom_fields/${id}`, { method: 'DELETE' })
+        if (!result.success) {
+          showError('Erreur lors de la suppression d\'un champ personnalisé')
+          await deps.onSaved()
+          return
+        }
+      }
+
+      let hasNewFields = false
+
+      for (const field of fields.value) {
+        const name = field.name.trim()
+        if (!name) continue
+
+        const options = field.type === 'select' ? parseOptions(field.optionsText) : []
+
+        if (!field.serverId) {
+          // POST new field
+          hasNewFields = true
+          const body: Record<string, unknown> = {
+            name,
+            type: field.type,
+            required: field.required,
+            options,
+            orderIndex: field.orderIndex,
+            machine: `/api/machines/${deps.machineId}`,
+          }
+
+          const result = await apiCall('/custom_fields', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/ld+json' },
+            body: JSON.stringify(body),
+          })
+          if (!result.success) {
+            showError('Erreur lors de la création d\'un champ personnalisé')
+            await deps.onSaved()
+            return
+          }
+        } else {
+          // PATCH modified field
+          const original = snapshot.get(field.serverId)
+          const originalOptions = Array.isArray(original?.options)
+            ? original.options.join('\n')
+            : ''
+          const currentOptions = field.type === 'select' ? field.optionsText : ''
+
+          const changed
+            = original?.name !== name
+            || original?.type !== field.type
+            || original?.required !== field.required
+            || normalizeLineEndings(originalOptions) !== normalizeLineEndings(currentOptions)
+            || original?.orderIndex !== field.orderIndex
+
+          if (changed) {
+            const body: Record<string, unknown> = {
+              name,
+              type: field.type,
+              required: field.required,
+              options,
+              orderIndex: field.orderIndex,
+            }
+
+            const result = await apiCall(`/custom_fields/${field.serverId}`, {
+              method: 'PATCH',
+              headers: { 'Content-Type': 'application/merge-patch+json' },
+              body: JSON.stringify(body),
+            })
+            if (!result.success) {
+              showError('Erreur lors de la mise à jour d\'un champ personnalisé')
+              await deps.onSaved()
+              return
+            }
+          }
+        }
+      }
+
+      // Initialize missing custom field values if new fields were created
+      if (hasNewFields) {
+        await apiCall(`/machines/${deps.machineId}/add-custom-fields`, {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/ld+json' },
+          body: JSON.stringify({}),
+        })
+      }
+
+      showSuccess('Champs personnalisés sauvegardés avec succès')
+      await deps.onSaved()
+    } catch {
+      showError('Erreur inattendue lors de la sauvegarde des champs personnalisés')
+      await deps.onSaved()
+    } finally {
+      saving.value = false
+    }
+  }
+
+  // --- Reinit ---
+
+  const reinit = (newDefs: InitialDef[]) => {
+    fields.value = hydrateFields(newDefs)
+    initialSnapshot.value = buildSnapshot(newDefs)
+  }
+
+  return {
+    fields,
+    saving,
+    dragState,
+    addField,
+    removeField,
+    onDragStart,
+    onDragEnter,
+    onDrop,
+    onDragEnd,
+    reorderClass,
+    saveDefinitions,
+    reinit,
+  }
+}
diff --git a/app/pages/machine/[id].vue b/app/pages/machine/[id].vue
index 11790cd..b00f6c7 100644
--- a/app/pages/machine/[id].vue
+++ b/app/pages/machine/[id].vue
@@ -57,12 +57,15 @@
         :has-machine-constructeur="d.hasMachineConstructeur.value"
         :visible-custom-fields="d.visibleMachineCustomFields.value"
         :get-machine-field-id="d.getMachineFieldId"
+        :machine-id="machineId"
+        :machine-custom-field-defs="d.machine.value?.customFields ?? []"
         @update:machine-name="d.machineName.value = $event"
         @update:machine-reference="d.machineReference.value = $event"
         @update:constructeur-ids="d.handleMachineConstructeurChange"
         @blur-field="d.updateMachineInfo"
         @set-custom-field-value="d.setMachineCustomFieldValue"
         @update-custom-field="d.updateMachineCustomField"
+        @custom-fields-saved="d.loadMachineData()"
       />
 
       <!-- Documents -->