diff --git a/url/Cargo.toml b/url/Cargo.toml
index 7ba83a15b..f634f6dad 100644
--- a/url/Cargo.toml
+++ b/url/Cargo.toml
@@ -35,6 +35,8 @@ serde = {version = "1.0", optional = true, features = ["derive"]}
 
 [features]
 default = []
+# Produce smaller binaries by omitting Unicode domain support
+disable_idna = []
 # UNSTABLE FEATURES (requires Rust nightly)
 # Enable to use the #[debugger_visualizer] attribute.
 debugger_visualizer = []
diff --git a/url/src/host.rs b/url/src/host.rs
index 9931c2f87..10a93d459 100644
--- a/url/src/host.rs
+++ b/url/src/host.rs
@@ -162,9 +162,22 @@ impl Host<String> {
     }
 
     /// convert domain with idna
+    #[cfg(not(feature = "disable_idna"))]
     fn domain_to_ascii(domain: &str) -> Result<String, ParseError> {
         idna::domain_to_ascii(domain).map_err(Into::into)
     }
+
+    /// checks domain is ascii
+    #[cfg(feature = "disable_idna")]
+    fn domain_to_ascii(domain: &str) -> Result<String, ParseError> {
+        // without idna feature, we can't verify that xn-- domains correctness
+        let domain = domain.to_lowercase();
+        if domain.is_ascii() && domain.split('.').all(|s| !s.starts_with("xn--")) {
+            Ok(domain)
+        } else {
+            Err(ParseError::InvalidDomainCharacter)
+        }
+    }
 }
 
 impl<S: AsRef<str>> fmt::Display for Host<S> {
diff --git a/url/src/lib.rs b/url/src/lib.rs
index 023a89a28..c07d1fe37 100644
--- a/url/src/lib.rs
+++ b/url/src/lib.rs
@@ -899,8 +899,11 @@ impl Url {
     /// assert_eq!(url.authority(), "user:password@example.com");
     /// let url = Url::parse("irc://àlex.рф.example.com:6667/foo")?;
     /// assert_eq!(url.authority(), "%C3%A0lex.%D1%80%D1%84.example.com:6667");
+    /// # #[cfg(not(feature = "disable_idna"))]
+    /// # {
     /// let url = Url::parse("http://àlex.рф.example.com:80/foo")?;
     /// assert_eq!(url.authority(), "xn--lex-8ka.xn--p1ai.example.com");
+    /// # }
     /// # Ok(())
     /// # }
     /// # run().unwrap();
diff --git a/url/src/origin.rs b/url/src/origin.rs
index 81193f510..4e221b04a 100644
--- a/url/src/origin.rs
+++ b/url/src/origin.rs
@@ -86,6 +86,7 @@ impl Origin {
     }
 
     /// <https://html.spec.whatwg.org/multipage/#unicode-serialisation-of-an-origin>
+    #[cfg(not(feature = "disable_idna"))]
     pub fn unicode_serialization(&self) -> String {
         match *self {
             Origin::Opaque(_) => "null".to_owned(),
diff --git a/url/src/parser.rs b/url/src/parser.rs
index c32090e20..eecce5b86 100644
--- a/url/src/parser.rs
+++ b/url/src/parser.rs
@@ -87,6 +87,7 @@ simple_enum_error! {
     Overflow => "URLs more than 4 GB are not supported",
 }
 
+#[cfg(not(feature = "disable_idna"))]
 impl From<::idna::Errors> for ParseError {
     fn from(_: ::idna::Errors) -> ParseError {
         ParseError::IdnaError
diff --git a/url/src/quirks.rs b/url/src/quirks.rs
index 0674ebb62..045ec4ec6 100644
--- a/url/src/quirks.rs
+++ b/url/src/quirks.rs
@@ -58,6 +58,7 @@ pub fn internal_components(url: &Url) -> InternalComponents {
 }
 
 /// https://url.spec.whatwg.org/#dom-url-domaintoascii
+#[cfg(not(feature = "disable_idna"))]
 pub fn domain_to_ascii(domain: &str) -> String {
     match Host::parse(domain) {
         Ok(Host::Domain(domain)) => domain,
diff --git a/url/tests/data.rs b/url/tests/data.rs
index dc4660b9b..c6a8221cc 100644
--- a/url/tests/data.rs
+++ b/url/tests/data.rs
@@ -39,7 +39,17 @@ fn urltestdata() {
             .expect("missing base key")
             .maybe_string();
         let input = entry.take_string("input");
-        let failure = entry.take_key("failure").is_some();
+        let failure = {
+            #[cfg(not(feature = "disable_idna"))]
+            {
+                entry.take_key("failure").is_some()
+            }
+
+            #[cfg(feature = "disable_idna")]
+            {
+                entry.take_key("is_idna").is_some() || entry.take_key("failure").is_some()
+            }
+        };
 
         let res = if let Some(base) = maybe_base {
             let base = match Url::parse(&base) {
diff --git a/url/tests/unit.rs b/url/tests/unit.rs
index 8957aaf32..bdbcbef1b 100644
--- a/url/tests/unit.rs
+++ b/url/tests/unit.rs
@@ -351,6 +351,7 @@ fn host_serialization() {
 }
 
 #[test]
+#[cfg(not(feature = "disable_idna"))]
 fn test_idna() {
     assert!("http://goșu.ro".parse::<Url>().is_ok());
     assert_eq!(
@@ -586,6 +587,7 @@ fn test_origin_opaque() {
 }
 
 #[test]
+#[cfg(not(feature = "disable_idna"))]
 fn test_origin_unicode_serialization() {
     let data = [
         ("http://😅.com", "http://😅.com"),
@@ -758,6 +760,7 @@ fn test_set_href() {
 }
 
 #[test]
+#[cfg(not(feature = "disable_idna"))]
 fn test_domain_encoding_quirks() {
     use url::quirks::{domain_to_ascii, domain_to_unicode};
 
@@ -811,8 +814,11 @@ fn test_windows_unc_path() {
     let url = Url::from_file_path(Path::new(r"\\host\share\path\file.txt")).unwrap();
     assert_eq!(url.as_str(), "file://host/share/path/file.txt");
 
-    let url = Url::from_file_path(Path::new(r"\\höst\share\path\file.txt")).unwrap();
-    assert_eq!(url.as_str(), "file://xn--hst-sna/share/path/file.txt");
+    #[cfg(not(feature = "disable_idna"))]
+    {
+        let url = Url::from_file_path(Path::new(r"\\höst\share\path\file.txt")).unwrap();
+        assert_eq!(url.as_str(), "file://xn--hst-sna/share/path/file.txt");
+    }
 
     let url = Url::from_file_path(Path::new(r"\\192.168.0.1\share\path\file.txt")).unwrap();
     assert_eq!(url.host(), Some(Host::Ipv4(Ipv4Addr::new(192, 168, 0, 1))));
@@ -1256,9 +1262,13 @@ fn test_authority() {
         url.authority(),
         "%C3%A0lex:%C3%A0lex@%C3%A0lex.%D1%80%D1%84.example.com:6667"
     );
-    let url = Url::parse("https://àlex:àlex@àlex.рф.example.com:443/foo").unwrap();
-    assert_eq!(
-        url.authority(),
-        "%C3%A0lex:%C3%A0lex@xn--lex-8ka.xn--p1ai.example.com"
-    );
+
+    #[cfg(not(feature = "disable_idna"))]
+    {
+        let url = Url::parse("https://àlex:àlex@àlex.рф.example.com:443/foo").unwrap();
+        assert_eq!(
+            url.authority(),
+            "%C3%A0lex:%C3%A0lex@xn--lex-8ka.xn--p1ai.example.com"
+        );
+    }
 }
diff --git a/url/tests/urltestdata.json b/url/tests/urltestdata.json
index 53d036886..e38302607 100644
--- a/url/tests/urltestdata.json
+++ b/url/tests/urltestdata.json
@@ -3617,7 +3617,8 @@
     "port": "",
     "pathname": "/",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   "Leading and trailing C0 control or space",
   {
@@ -3649,7 +3650,8 @@
     "port": "",
     "pathname": "/",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   "Invalid unicode characters should fail... U+FDD0 is disallowed; %ef%b7%90 is U+FDD0",
   {
@@ -3735,7 +3737,8 @@
     "port": "",
     "pathname": "/",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   "URL spec forbids the following. https://www.w3.org/Bugs/Public/show_bug.cgi?id=24257",
   {
@@ -3773,7 +3776,8 @@
     "port": "",
     "pathname": "/",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   {
     "input": "https://faß.ExAmPlE/",
@@ -3788,7 +3792,8 @@
     "port": "",
     "pathname": "/",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   {
     "input": "sc://faß.ExAmPlE/",
@@ -3889,7 +3894,8 @@
     "port": "",
     "pathname": "/",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   "Domains with empty labels",
   {
@@ -5325,7 +5331,8 @@
     "port": "",
     "pathname": "/",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   {
     "input": "https://%e2%98%83",
@@ -5340,7 +5347,8 @@
     "port": "",
     "pathname": "/",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   "# tests from jsdom/whatwg-url designed for code coverage",
   {
@@ -8172,7 +8180,8 @@
     "port": "",
     "pathname": "/p",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   {
     "input": "file://a%C2%ADb/p",
@@ -8186,7 +8195,8 @@
     "port": "",
     "pathname": "/p",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   "IDNA hostnames which get mapped to 'localhost'",
   {
@@ -8201,7 +8211,8 @@
     "port": "",
     "pathname": "/usr/bin",
     "search": "",
-    "hash": ""
+    "hash": "",
+    "is_idna": true
   },
   "Empty host after the domain to ASCII",
   {