diff --git a/native/account/log-in-panel.react.js b/native/account/log-in-panel.react.js
--- a/native/account/log-in-panel.react.js
+++ b/native/account/log-in-panel.react.js
@@ -339,7 +339,7 @@
     } catch (e) {
       const messageForException = getMessageForException(e);
       if (
-        messageForException === 'user not found' ||
+        messageForException === 'user_not_found' ||
         messageForException === 'login failed'
       ) {
         Alert.alert(
diff --git a/native/account/registration/registration-server-call.js b/native/account/registration/registration-server-call.js
--- a/native/account/registration/registration-server-call.js
+++ b/native/account/registration/registration-server-call.js
@@ -119,14 +119,14 @@
           );
         } catch (e) {
           const messageForException = getMessageForException(e);
-          if (messageForException === 'username reserved') {
+          if (messageForException === 'username_reserved') {
             Alert.alert(
               usernameReservedAlertDetails.title,
               usernameReservedAlertDetails.message,
               [{ text: 'OK', onPress: onAlertAcknowledged }],
               { cancelable: !onAlertAcknowledged },
             );
-          } else if (messageForException === 'username already exists') {
+          } else if (messageForException === 'username_already_exists') {
             Alert.alert(
               usernameTakenAlertDetails.title,
               usernameTakenAlertDetails.message,
diff --git a/services/identity/src/client_service.rs b/services/identity/src/client_service.rs
--- a/services/identity/src/client_service.rs
+++ b/services/identity/src/client_service.rs
@@ -13,7 +13,7 @@
 
 // Workspace crate imports
 use crate::config::CONFIG;
-use crate::constants::error_types;
+use crate::constants::{error_types, tonic_status_messages};
 use crate::database::{
   DBDeviceTypeInt, DatabaseClient, DeviceType, KeyPayload
 };
@@ -124,11 +124,15 @@
       .map_err(handle_db_error)?;
 
     if username_in_reserved_usernames_table {
-      return Err(tonic::Status::already_exists("username already exists"));
+      return Err(tonic::Status::already_exists(
+        tonic_status_messages::USERNAME_ALREADY_EXISTS,
+      ));
     }
 
     if RESERVED_USERNAME_SET.contains(&message.username) {
-      return Err(tonic::Status::invalid_argument("username reserved"));
+      return Err(tonic::Status::invalid_argument(
+        tonic_status_messages::USERNAME_RESERVED,
+      ));
     }
 
     if let Some(fid) = &message.farcaster_id {
@@ -173,7 +177,9 @@
     self.check_username_taken(&message.username).await?;
 
     if RESERVED_USERNAME_SET.contains(&message.username) {
-      return Err(tonic::Status::invalid_argument("username reserved"));
+      return Err(tonic::Status::invalid_argument(
+        tonic_status_messages::USERNAME_RESERVED,
+      ));
     }
 
     let username_in_reserved_usernames_table = self
@@ -317,7 +323,9 @@
           ));
         }
 
-        return Err(tonic::Status::not_found("user not found"));
+        return Err(tonic::Status::not_found(
+          tonic_status_messages::USER_NOT_FOUND,
+        ));
       };
 
     let flattened_device_key_upload =
@@ -481,7 +489,9 @@
         ));
       }
 
-      return Err(tonic::Status::not_found("user not found"));
+      return Err(tonic::Status::not_found(
+        tonic_status_messages::USER_NOT_FOUND,
+      ));
     };
 
     self
@@ -563,7 +573,7 @@
 
     if username_in_reserved_usernames_table {
       return Err(tonic::Status::already_exists(
-        "wallet address already exists",
+        tonic_status_messages::WALLET_ADDRESS_TAKEN,
       ));
     }
 
@@ -646,7 +656,7 @@
       .map_err(handle_db_error)?;
     if !wallet_address_in_reserved_usernames_table {
       return Err(tonic::Status::permission_denied(
-        "wallet address not reserved",
+        tonic_status_messages::WALLET_ADDRESS_NOT_RESERVED,
       ));
     }
 
@@ -727,7 +737,9 @@
       .get_user_identity(&user_id)
       .await
       .map_err(handle_db_error)?
-      .ok_or_else(|| tonic::Status::not_found("user not found"))?;
+      .ok_or_else(|| {
+        tonic::Status::not_found(tonic_status_messages::USER_NOT_FOUND)
+      })?;
 
     let Some(device_list) = self
       .client
@@ -799,9 +811,10 @@
       self.client.get_user_identity(&user_id),
       self.client.get_current_device_list(&user_id)
     );
-    let user_identity = identity_response
-      .map_err(handle_db_error)?
-      .ok_or_else(|| tonic::Status::not_found("user not found"))?;
+    let user_identity =
+      identity_response.map_err(handle_db_error)?.ok_or_else(|| {
+        tonic::Status::not_found(tonic_status_messages::USER_NOT_FOUND)
+      })?;
 
     let device_list = device_list_response
       .map_err(handle_db_error)?
@@ -1008,7 +1021,9 @@
       .await
       .map_err(handle_db_error)?;
     if username_taken {
-      return Err(tonic::Status::already_exists("username already exists"));
+      return Err(tonic::Status::already_exists(
+        tonic_status_messages::USERNAME_ALREADY_EXISTS,
+      ));
     }
     Ok(())
   }
@@ -1024,7 +1039,7 @@
       .map_err(handle_db_error)?;
     if wallet_address_taken {
       return Err(tonic::Status::already_exists(
-        "wallet address already exists",
+        tonic_status_messages::WALLET_ADDRESS_TAKEN,
       ));
     }
     Ok(())
@@ -1174,8 +1189,9 @@
 fn construct_flattened_device_key_upload(
   message: &impl DeviceKeyUploadActions,
 ) -> Result<FlattenedDeviceKeyUpload, tonic::Status> {
-  let key_info = KeyPayload::from_str(&message.payload()?)
-    .map_err(|_| tonic::Status::invalid_argument("malformed payload"))?;
+  let key_info = KeyPayload::from_str(&message.payload()?).map_err(|_| {
+    tonic::Status::invalid_argument(tonic_status_messages::MALFORMED_PAYLOAD)
+  })?;
 
   let flattened_device_key_upload = FlattenedDeviceKeyUpload {
     device_id_key: key_info.primary_identity_public_keys.ed25519,
diff --git a/services/identity/src/constants.rs b/services/identity/src/constants.rs
--- a/services/identity/src/constants.rs
+++ b/services/identity/src/constants.rs
@@ -219,6 +219,16 @@
 // Tonic Status Messages
 pub mod tonic_status_messages {
   pub const UNEXPECTED_MESSAGE_DATA: &str = "unexpected_message_data";
+  pub const SIGNATURE_INVALID: &str = "signature_invalid";
+  pub const MALFORMED_KEY: &str = "malformed_key";
+  pub const VERIFICATION_FAILED: &str = "verification_failed";
+  pub const MALFORMED_PAYLOAD: &str = "malformed_payload";
+  pub const INVALID_DEVICE_LIST_PAYLOAD: &str = "invalid_device_list_payload";
+  pub const USERNAME_ALREADY_EXISTS: &str = "username_already_exists";
+  pub const USERNAME_RESERVED: &str = "username_reserved";
+  pub const WALLET_ADDRESS_TAKEN: &str = "wallet_address_taken";
+  pub const WALLET_ADDRESS_NOT_RESERVED: &str = "wallet_address_not_reserved";
+  pub const USER_NOT_FOUND: &str = "user_not_found";
 }
 
 // Tunnelbroker
diff --git a/services/identity/src/device_list.rs b/services/identity/src/device_list.rs
--- a/services/identity/src/device_list.rs
+++ b/services/identity/src/device_list.rs
@@ -3,7 +3,9 @@
 use tracing::{debug, error, warn};
 
 use crate::{
-  constants::{error_types, DEVICE_LIST_TIMESTAMP_VALID_FOR},
+  constants::{
+    error_types, tonic_status_messages, DEVICE_LIST_TIMESTAMP_VALID_FOR,
+  },
   database::{DeviceListRow, DeviceListUpdate},
   error::DeviceListError,
   grpc_services::protos::auth::UpdateDeviceListRequest,
@@ -44,7 +46,9 @@
     serde_json::from_str(&self.raw_device_list.replace(r#"\""#, r#"""#))
       .map_err(|err| {
         warn!("Failed to deserialize raw device list: {}", err);
-        tonic::Status::invalid_argument("invalid device list payload")
+        tonic::Status::invalid_argument(
+          tonic_status_messages::INVALID_DEVICE_LIST_PAYLOAD,
+        )
       })
   }
 
@@ -89,7 +93,9 @@
   fn try_from(request: UpdateDeviceListRequest) -> Result<Self, Self::Error> {
     request.new_device_list.parse().map_err(|err| {
       warn!("Failed to deserialize device list update: {}", err);
-      tonic::Status::invalid_argument("invalid device list payload")
+      tonic::Status::invalid_argument(
+        tonic_status_messages::INVALID_DEVICE_LIST_PAYLOAD,
+      )
     })
   }
 }
diff --git a/services/identity/src/grpc_services/authenticated.rs b/services/identity/src/grpc_services/authenticated.rs
--- a/services/identity/src/grpc_services/authenticated.rs
+++ b/services/identity/src/grpc_services/authenticated.rs
@@ -5,7 +5,7 @@
 use crate::device_list::SignedDeviceList;
 use crate::{
   client_service::{handle_db_error, UpdateState, WorkflowInProgress},
-  constants::{error_types, request_metadata},
+  constants::{error_types, request_metadata, tonic_status_messages},
   database::DatabaseClient,
   grpc_services::shared::{get_platform_metadata, get_value},
 };
@@ -133,7 +133,9 @@
       .get_keys_for_user(user_id, true)
       .await
       .map_err(handle_db_error)?
-      .ok_or_else(|| tonic::Status::not_found("user not found"))?;
+      .ok_or_else(|| {
+        tonic::Status::not_found(tonic_status_messages::USER_NOT_FOUND)
+      })?;
 
     let transformed_devices = devices_map
       .into_iter()
@@ -158,7 +160,9 @@
       .get_keys_for_user(user_id, false)
       .await
       .map_err(handle_db_error)?
-      .ok_or_else(|| tonic::Status::not_found("user not found"))?;
+      .ok_or_else(|| {
+        tonic::Status::not_found(tonic_status_messages::USER_NOT_FOUND)
+      })?;
 
     let transformed_devices = devices_map
       .into_iter()
@@ -170,7 +174,9 @@
       .get_user_identity(user_id)
       .await
       .map_err(handle_db_error)?
-      .ok_or_else(|| tonic::Status::not_found("user not found"))?;
+      .ok_or_else(|| {
+        tonic::Status::not_found(tonic_status_messages::USER_NOT_FOUND)
+      })?;
 
     Ok(tonic::Response::new(InboundKeysForUserResponse {
       devices: transformed_devices,
@@ -190,7 +196,9 @@
       .get_user_identity(&message.user_id)
       .await
       .map_err(handle_db_error)?
-      .ok_or_else(|| tonic::Status::not_found("user not found"))?;
+      .ok_or_else(|| {
+        tonic::Status::not_found(tonic_status_messages::USER_NOT_FOUND)
+      })?;
 
     let Some(keyserver_info) = self
       .db_client
@@ -415,7 +423,9 @@
     let Some((username, password_file_bytes)) =
       maybe_username_and_password_file
     else {
-      return Err(tonic::Status::not_found("user not found"));
+      return Err(tonic::Status::not_found(
+        tonic_status_messages::USER_NOT_FOUND,
+      ));
     };
 
     let mut server_login = comm_opaque2::server::Login::new();
diff --git a/services/identity/src/grpc_utils.rs b/services/identity/src/grpc_utils.rs
--- a/services/identity/src/grpc_utils.rs
+++ b/services/identity/src/grpc_utils.rs
@@ -67,21 +67,30 @@
 ) -> Result<(), Status> {
   let signature_bytes = general_purpose::STANDARD_NO_PAD
     .decode(signature)
-    .map_err(|_| Status::invalid_argument("signature invalid"))?;
+    .map_err(|_| {
+      Status::invalid_argument(tonic_status_messages::SIGNATURE_INVALID)
+    })?;
 
-  let signature = Signature::from_bytes(&signature_bytes)
-    .map_err(|_| Status::invalid_argument("signature invalid"))?;
+  let signature = Signature::from_bytes(&signature_bytes).map_err(|_| {
+    Status::invalid_argument(tonic_status_messages::SIGNATURE_INVALID)
+  })?;
 
   let public_key_bytes = general_purpose::STANDARD_NO_PAD
     .decode(signing_public_key)
-    .map_err(|_| Status::failed_precondition("malformed key"))?;
+    .map_err(|_| {
+      Status::failed_precondition(tonic_status_messages::MALFORMED_KEY)
+    })?;
 
   let public_key: PublicKey = PublicKey::from_bytes(&public_key_bytes)
-    .map_err(|_| Status::failed_precondition("malformed key"))?;
+    .map_err(|_| {
+      Status::failed_precondition(tonic_status_messages::MALFORMED_KEY)
+    })?;
 
   public_key
     .verify(message.as_bytes(), &signature)
-    .map_err(|_| Status::permission_denied("verification failed"))?;
+    .map_err(|_| {
+      Status::permission_denied(tonic_status_messages::VERIFICATION_FAILED)
+    })?;
   Ok(())
 }
 
@@ -312,13 +321,14 @@
     }
     let signed_list: SignedDeviceList = payload.parse().map_err(|err| {
       warn!("Failed to deserialize initial device list: {}", err);
-      tonic::Status::invalid_argument("invalid device list payload")
+      tonic::Status::invalid_argument(
+        tonic_status_messages::INVALID_DEVICE_LIST_PAYLOAD,
+      )
     })?;
 
-    let key_info = self
-      .payload()?
-      .parse::<KeyPayload>()
-      .map_err(|_| tonic::Status::invalid_argument("malformed payload"))?;
+    let key_info = self.payload()?.parse::<KeyPayload>().map_err(|_| {
+      tonic::Status::invalid_argument(tonic_status_messages::MALFORMED_PAYLOAD)
+    })?;
     let primary_device_id = key_info.primary_identity_public_keys.ed25519;
 
     let update_payload = DeviceListUpdate::try_from(signed_list.clone())?;
diff --git a/web/account/siwe-login-form.react.js b/web/account/siwe-login-form.react.js
--- a/web/account/siwe-login-form.react.js
+++ b/web/account/siwe-login-form.react.js
@@ -174,7 +174,7 @@
         return await walletLogIn(walletAddress, siweMessage, siweSignature);
       } catch (e) {
         const messageForException = getMessageForException(e);
-        if (messageForException === 'user not found') {
+        if (messageForException === 'user_not_found') {
           setError('account_does_not_exist');
         } else if (
           messageForException === 'client_version_unsupported' ||
diff --git a/web/account/traditional-login-form.react.js b/web/account/traditional-login-form.react.js
--- a/web/account/traditional-login-form.react.js
+++ b/web/account/traditional-login-form.react.js
@@ -128,7 +128,7 @@
       setPassword('');
       const messageForException = getMessageForException(e);
       if (
-        messageForException === 'user not found' ||
+        messageForException === 'user_not_found' ||
         messageForException === 'login failed'
       ) {
         setErrorMessage('incorrect username or password');