diff --git a/src/couch-design/validate-doc-update.ts b/src/couch-design/validate-doc-update.ts
new file mode 100644
index 0000000..5af7ffa
--- /dev/null
+++ b/src/couch-design/validate-doc-update.ts
@@ -0,0 +1,21 @@
+import IAccount from '@/models/IAccount'
+import ITransaction from '@/models/ITransaction'
+import IExchange from '@/models/IExchange'
+
+type Doc = IAccount | ITransaction | IExchange
+
+interface IUserContext {
+  db: string
+  name: string | null
+  roles: string[]
+}
+
+export default {
+  validate_doc_update(newDoc: Doc, oldDoc: Doc, userCtx: IUserContext) {
+    if (newDoc.doctype === 'account' && oldDoc.doctype === 'account') {
+      if (newDoc.userIds.indexOf(userCtx.name || '') < 0) {
+        throw { forbidden: 'You do not have rights to update this account' }
+      }
+    }
+  }
+}
diff --git a/src/models/IAccount.ts b/src/models/IAccount.ts
index c25d8f6..4d35e82 100644
--- a/src/models/IAccount.ts
+++ b/src/models/IAccount.ts
@@ -3,6 +3,7 @@ import IUser from '@/models/IUser'
 import ICurrency from '@/models/ICurrency'
 
 export default interface IAccount extends IModel {
+  doctype: 'account'
   name: string
   color: string | null
   slug?: string
diff --git a/src/models/IExchange.ts b/src/models/IExchange.ts
index c9ea731..a428288 100644
--- a/src/models/IExchange.ts
+++ b/src/models/IExchange.ts
@@ -1,6 +1,7 @@
 import IModel from '@/models/IModel'
 
 export default interface IExchange extends IModel {
+  doctype: 'exchange'
   base: string
   date: string
   timestamp?: string
diff --git a/src/models/IModel.ts b/src/models/IModel.ts
index 6819f9a..8ccc0a9 100644
--- a/src/models/IModel.ts
+++ b/src/models/IModel.ts
@@ -3,5 +3,4 @@ export default interface IModel {
   _rev?: string
   _deleted?: boolean
   _conflicts?: string[]
-  doctype?: string
 }
diff --git a/src/models/ITransaction.ts b/src/models/ITransaction.ts
index 629624f..c2311de 100644
--- a/src/models/ITransaction.ts
+++ b/src/models/ITransaction.ts
@@ -7,6 +7,7 @@ import ISplit from '@/models/ISplit'
 import ILocation from './ILocation'
 
 export default interface ITransaction extends IModel {
+  doctype: 'transaction'
   name: string
   accountId: string
   date: Date
diff --git a/src/services/ExchangeService.ts b/src/services/ExchangeService.ts
index 9ad942c..40b294e 100644
--- a/src/services/ExchangeService.ts
+++ b/src/services/ExchangeService.ts
@@ -35,6 +35,7 @@ class ExchangeService {
         if (!needFetch) {
           exchange = {
             base,
+            doctype: 'exchange',
             date: formattedDate,
             rates: {
               [base]: 1