diff --git a/serde/Cargo.toml b/serde/Cargo.toml
index c1374189..b8da592e 100644
--- a/serde/Cargo.toml
+++ b/serde/Cargo.toml
@@ -3,7 +3,7 @@ name = "serde"
 version = "1.0.140" # remember to update html_root_url and serde_derive dependency
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
-categories = ["encoding"]
+categories = ["encoding", "no-std"]
 description = "A generic serialization/deserialization framework"
 documentation = "https://docs.serde.rs/serde/"
 homepage = "https://serde.rs"
diff --git a/serde_derive/Cargo.toml b/serde_derive/Cargo.toml
index 06e0557f..fd8417a1 100644
--- a/serde_derive/Cargo.toml
+++ b/serde_derive/Cargo.toml
@@ -2,6 +2,7 @@
 name = "serde_derive"
 version = "1.0.140" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
+categories = ["no-std"]
 description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"
 documentation = "https://serde.rs/derive.html"
 homepage = "https://serde.rs"
diff --git a/serde_test/Cargo.toml b/serde_test/Cargo.toml
index 0c93f260..be8085a9 100644
--- a/serde_test/Cargo.toml
+++ b/serde_test/Cargo.toml
@@ -3,6 +3,7 @@ name = "serde_test"
 version = "1.0.140" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
+categories = ["development-tools::testing"]
 description = "Token De/Serializer for testing De/Serialize implementations"
 documentation = "https://docs.serde.rs/serde_test/"
 homepage = "https://serde.rs"