diff --git a/{{cookiecutter.app_name}}/buf.lock b/{{cookiecutter.app_name}}/buf.lock
index e839663..0ab94f1 100644
--- a/{{cookiecutter.app_name}}/buf.lock
+++ b/{{cookiecutter.app_name}}/buf.lock
@@ -1,18 +1,18 @@
 # Generated by buf. DO NOT EDIT.
 version: v2
 deps:
-  - name: buf.build/envoyproxy/protoc-gen-validate
-    commit: daf171c6cdb54629b5f51e345a79e4dd
-    digest: b5:c745e1521879f43740230b1df673d0729f55704efefdcfc489d4a0a2d40c92a26cacfeab62813403040a8b180142d53b398c7ca784a065e43823605ee49681de
+  - name: buf.build/bufbuild/protovalidate
+    commit: 80ab13bee0bf4272b6161a72bf7034e0
+    digest: b5:1aa6a965be5d02d64e1d81954fa2e78ef9d1e33a0c30f92bc2626039006a94deb3a5b05f14ed8893f5c3ffce444ac008f7e968188ad225c4c29c813aa5f2daa1
   - name: buf.build/googleapis/googleapis
-    commit: 546238c53f7340c6a2a6099fb863bc1b
-    digest: b5:e017bbf31a3f912e2b969c03c3aa711f466cfe104f510865d1a8ede1be490240aabd4cca5865459a0f15222747284395f98afc094b0fd086e8917a5a7bdd9db0
+    commit: 536964a08a534d51b8f30f2d6751f1f9
+    digest: b5:3e05d27e797b00c345fadd3c15cf0e16c4cc693036a55059721e66d6ce22a96264a4897658c9243bb0874fa9ca96e437589eb512189d2754604a626c632f6030
   - name: buf.build/grpc-ecosystem/grpc-gateway
-    commit: 4c5ba75caaf84e928b7137ae5c18c26a
-    digest: b5:c113e62fb3b29289af785866cae062b55ec8ae19ab3f08f3004098928fbca657730a06810b2012951294326b95669547194fa84476b9e9b688d4f8bf77a0691d
+    commit: 6467306b4f624747aaf6266762ee7a1c
+    digest: b5:c2caa61467d992749812c909f93c07e9a667da33c758a7c1973d63136c23b3cafcc079985b12cdf54a10049ed3297418f1eda42cdffdcf34113792dcc3a990af
   - name: buf.build/grpc-ecosystem/protoc-gen-swagger
     commit: 177bd018c960492d831aee5e88594dec
     digest: b5:62717e8b4ece73a14db1968e48f814f890431dacdde35f631d2e9412a1522a13eaa9d208875e809a9c772bc52d56a04128a1befd6445163826984f0856797f83
   - name: buf.build/grpc/grpc
-    commit: 9327911dce6e4b51a37ad5e93578c833
-    digest: b5:4778e2461d27be4f17d557ee958ba034281151f838c1608c7c367c8e81d20def24466cd7173a5e9cef66db26dda9bb25f66bc32aa7b26957640fc2a98b7db02a
+    commit: 1730f7242d0f45138a638b7612d46586
+    digest: b5:2998161006b920a3e2cadf8855e008a7a5f4922a5ac699695db3e08beac0f3bee5429a71223b645bc5145b9725309768dcd36937be4b886b947994c45320d795
diff --git a/{{cookiecutter.app_name}}/buf.yaml b/{{cookiecutter.app_name}}/buf.yaml
index 29c812a..3abc336 100644
--- a/{{cookiecutter.app_name}}/buf.yaml
+++ b/{{cookiecutter.app_name}}/buf.yaml
@@ -22,7 +22,7 @@ modules:
     lint:
       disallow_comment_ignores: true
 deps:
-  - buf.build/envoyproxy/protoc-gen-validate
+  - buf.build/bufbuild/protovalidate
   - buf.build/googleapis/googleapis
   - buf.build/grpc/grpc
   - buf.build/grpc-ecosystem/protoc-gen-swagger
diff --git a/{{cookiecutter.app_name}}/proto/{{cookiecutter.app_name|lower}}.proto b/{{cookiecutter.app_name}}/proto/{{cookiecutter.app_name|lower}}.proto
index 5dbbf70..2d3a7e5 100644
--- a/{{cookiecutter.app_name}}/proto/{{cookiecutter.app_name|lower}}.proto
+++ b/{{cookiecutter.app_name}}/proto/{{cookiecutter.app_name|lower}}.proto
@@ -4,6 +4,7 @@ package {{cookiecutter.grpc_package}};
 
 option go_package = "{{cookiecutter.source_path}}/{{cookiecutter.app_name}}/proto;{{cookiecutter.app_name|lower|replace('.', '_')}}";
 
+import "buf/validate/validate.proto";
 import "google/api/annotations.proto";
 import "protoc-gen-openapiv2/options/annotations.proto";
 import "google/api/httpbody.proto";
@@ -23,7 +24,9 @@ option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_swagger) = {
 };
 
 message EchoRequest{
-  string msg = 1;
+  // msg must be at least 1 character — validated automatically by the
+  // protovalidate interceptor. Sending an empty string returns InvalidArgument.
+  string msg = 1 [(buf.validate.field).string.min_len = 1];
 }
 message EchoResponse{
   string msg = 1;