diff --git a/common/api.yaml b/common/api.yaml
index 20dedbe..2ca6337 100644
--- a/common/api.yaml
+++ b/common/api.yaml
@@ -409,6 +409,59 @@ paths:
         404:
           description: The task could not be found.
 
+  /api/transfer:
+    post:
+      summary: Transfer amount between allowances
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              properties:
+                from:
+                  type: integer
+                  description: Source allowance ID
+                to:
+                  type: integer
+                  description: Destination allowance ID
+                amount:
+                  type: number
+                  format: float
+                  description: Amount to transfer
+              required:
+                - from
+                - to
+                - amount
+      responses:
+        '200':
+          description: Transfer successful
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  message:
+                    type: string
+        '400':
+          description: Invalid request
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  error:
+                    type: string
+        '404':
+          description: Allowance not found
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  error:
+                    type: string
+
 components:
   schemas:
     task: