diff --git a/common/proto/accounting.proto b/common/proto/accounting.proto
index 2671953..c61f0d8 100644
--- a/common/proto/accounting.proto
+++ b/common/proto/accounting.proto
@@ -8,6 +8,10 @@ service Accounting {
   // all supplied lines atomically when journal_id identifies an existing one.
   rpc PostJournal(PostJournalRequest) returns (Journal);
 
+  // Permanently lock a balanced journal. This is an explicit action; becoming
+  // balanced never locks a journal automatically.
+  rpc LockJournal(LockJournalRequest) returns (Journal);
+
   // Return journal lines and credits-minus-debits informational balance.
   rpc GetJournal(GetJournalRequest) returns (Journal);
 
@@ -58,6 +62,11 @@ message JournalLineInput {
   string description = 4;
 }
 
+message LockJournalRequest {
+  string profile_name = 1;
+  int64 journal_id = 2;
+}
+
 message GetJournalRequest {
   string profile_name = 1;
   int64 journal_id = 2;
@@ -149,4 +158,7 @@ message Journal {
   string total_credit = 8;
   // Informational difference calculated as credits minus debits.
   string balance = 9;
+  bool locked = 10;
+  string locked_at = 11;
+  string locked_by_user_id = 12;
 }
diff --git a/common/src/proto/descriptor.bin b/common/src/proto/descriptor.bin
index 57d2f0b..8346d4a 100644
Binary files a/common/src/proto/descriptor.bin and b/common/src/proto/descriptor.bin differ
diff --git a/common/src/proto/komp_ac.accounting.rs b/common/src/proto/komp_ac.accounting.rs
index 00f9434..2b83439 100644
--- a/common/src/proto/komp_ac.accounting.rs
+++ b/common/src/proto/komp_ac.accounting.rs
@@ -31,6 +31,13 @@ pub struct JournalLineInput {
     pub description: ::prost::alloc::string::String,
 }
 #[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
+pub struct LockJournalRequest {
+    #[prost(string, tag = "1")]
+    pub profile_name: ::prost::alloc::string::String,
+    #[prost(int64, tag = "2")]
+    pub journal_id: i64,
+}
+#[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
 pub struct GetJournalRequest {
     #[prost(string, tag = "1")]
     pub profile_name: ::prost::alloc::string::String,
@@ -167,6 +174,12 @@ pub struct Journal {
     /// Informational difference calculated as credits minus debits.
     #[prost(string, tag = "9")]
     pub balance: ::prost::alloc::string::String,
+    #[prost(bool, tag = "10")]
+    pub locked: bool,
+    #[prost(string, tag = "11")]
+    pub locked_at: ::prost::alloc::string::String,
+    #[prost(string, tag = "12")]
+    pub locked_by_user_id: ::prost::alloc::string::String,
 }
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, ::prost::Enumeration)]
 #[repr(i32)]
@@ -313,6 +326,29 @@ pub mod accounting_client {
                 .insert(GrpcMethod::new("komp_ac.accounting.Accounting", "PostJournal"));
             self.inner.unary(req, path, codec).await
         }
+        /// Permanently lock a balanced journal. This is an explicit action; becoming
+        /// balanced never locks a journal automatically.
+        pub async fn lock_journal(
+            &mut self,
+            request: impl tonic::IntoRequest<super::LockJournalRequest>,
+        ) -> std::result::Result<tonic::Response<super::Journal>, tonic::Status> {
+            self.inner
+                .ready()
+                .await
+                .map_err(|e| {
+                    tonic::Status::unknown(
+                        format!("Service was not ready: {}", e.into()),
+                    )
+                })?;
+            let codec = tonic_prost::ProstCodec::default();
+            let path = http::uri::PathAndQuery::from_static(
+                "/komp_ac.accounting.Accounting/LockJournal",
+            );
+            let mut req = request.into_request();
+            req.extensions_mut()
+                .insert(GrpcMethod::new("komp_ac.accounting.Accounting", "LockJournal"));
+            self.inner.unary(req, path, codec).await
+        }
         /// Return journal lines and credits-minus-debits informational balance.
         pub async fn get_journal(
             &mut self,
@@ -443,6 +479,12 @@ pub mod accounting_server {
             &self,
             request: tonic::Request<super::PostJournalRequest>,
         ) -> std::result::Result<tonic::Response<super::Journal>, tonic::Status>;
+        /// Permanently lock a balanced journal. This is an explicit action; becoming
+        /// balanced never locks a journal automatically.
+        async fn lock_journal(
+            &self,
+            request: tonic::Request<super::LockJournalRequest>,
+        ) -> std::result::Result<tonic::Response<super::Journal>, tonic::Status>;
         /// Return journal lines and credits-minus-debits informational balance.
         async fn get_journal(
             &self,
@@ -593,6 +635,51 @@ pub mod accounting_server {
                     };
                     Box::pin(fut)
                 }
+                "/komp_ac.accounting.Accounting/LockJournal" => {
+                    #[allow(non_camel_case_types)]
+                    struct LockJournalSvc<T: Accounting>(pub Arc<T>);
+                    impl<
+                        T: Accounting,
+                    > tonic::server::UnaryService<super::LockJournalRequest>
+                    for LockJournalSvc<T> {
+                        type Response = super::Journal;
+                        type Future = BoxFuture<
+                            tonic::Response<Self::Response>,
+                            tonic::Status,
+                        >;
+                        fn call(
+                            &mut self,
+                            request: tonic::Request<super::LockJournalRequest>,
+                        ) -> Self::Future {
+                            let inner = Arc::clone(&self.0);
+                            let fut = async move {
+                                <T as Accounting>::lock_journal(&inner, request).await
+                            };
+                            Box::pin(fut)
+                        }
+                    }
+                    let accept_compression_encodings = self.accept_compression_encodings;
+                    let send_compression_encodings = self.send_compression_encodings;
+                    let max_decoding_message_size = self.max_decoding_message_size;
+                    let max_encoding_message_size = self.max_encoding_message_size;
+                    let inner = self.inner.clone();
+                    let fut = async move {
+                        let method = LockJournalSvc(inner);
+                        let codec = tonic_prost::ProstCodec::default();
+                        let mut grpc = tonic::server::Grpc::new(codec)
+                            .apply_compression_config(
+                                accept_compression_encodings,
+                                send_compression_encodings,
+                            )
+                            .apply_max_message_size_config(
+                                max_decoding_message_size,
+                                max_encoding_message_size,
+                            );
+                        let res = grpc.unary(method, req).await;
+                        Ok(res)
+                    };
+                    Box::pin(fut)
+                }
                 "/komp_ac.accounting.Accounting/GetJournal" => {
                     #[allow(non_camel_case_types)]
                     struct GetJournalSvc<T: Accounting>(pub Arc<T>);
diff --git a/server b/server
index 3d145bf..58f10e0 160000
--- a/server
+++ b/server
@@ -1 +1 @@
-Subproject commit 3d145bfc4b79c9e96fc25bff21c645d869ef7f3f
+Subproject commit 58f10e086a4c6b245748d0a031fce4c2c98daa9b
diff --git a/tui-pages b/tui-pages
index 5ff36b0..e0f2ccb 160000
--- a/tui-pages
+++ b/tui-pages
@@ -1 +1 @@
-Subproject commit 5ff36b0aea5d3b7fb5918da8d51997e6f1d4429a
+Subproject commit e0f2ccb3be92d3baaff532bbfbd217b936ea3fc1