diff --git a/idna/Cargo.toml b/idna/Cargo.toml
index a495de299..d8c75785a 100644
--- a/idna/Cargo.toml
+++ b/idna/Cargo.toml
@@ -32,7 +32,7 @@ tester = "0.9"
 serde_json = { version = "1.0" }
 
 [dependencies]
-unicode-bidi = { version = "0.3.10", default-features = false, features = ["hardcoded-data"] }
+unicode-bidi = { version = "0.3.10", default-features = false, features = ["hardcoded-data", "alloc"] }
 unicode-normalization = { version = "0.1.22", default-features = false }
 
 [[bench]]