diff --git a/Cargo.toml b/Cargo.toml
index 8cbd02eac..a3e354616 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -69,6 +69,7 @@ __rustls = ["hyper-rustls", "tokio-rustls", "rustls", "__tls"]
 __internal_proxy_sys_no_cache = []
 
 [dependencies]
+base64 = "0.13"
 http = "0.2"
 url = "2.2"
 bytes = "0.5"
@@ -79,7 +80,6 @@ mime_guess = "2.0"
 serde_json = { version = "1.0", optional = true }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
-base64 = "0.13"
 encoding_rs = "0.8"
 futures-core = { version = "0.3.0", default-features = false }
 futures-util = { version = "0.3.0", default-features = false }
diff --git a/src/wasm/request.rs b/src/wasm/request.rs
index df7808345..6ca7f32ea 100644
--- a/src/wasm/request.rs
+++ b/src/wasm/request.rs
@@ -1,6 +1,8 @@
 use std::convert::TryFrom;
 use std::fmt;
+use std::io::Write;
 
+use base64::write::EncoderWriter as Base64Encoder;
 use http::{request::Parts, Method, Request as HttpRequest};
 use url::Url;
 #[cfg(feature = "json")]
@@ -172,6 +174,25 @@ impl RequestBuilder {
         self
     }
 
+    /// Enable HTTP basic authentication.
+    pub fn basic_auth<U, P>(self, username: U, password: Option<P>) -> RequestBuilder
+        where
+            U: fmt::Display,
+            P: fmt::Display,
+    {
+        let mut header_value = b"Basic ".to_vec();
+        {
+            let mut encoder = Base64Encoder::new(&mut header_value, base64::STANDARD);
+            // The unwraps here are fine because Vec::write* is infallible.
+            write!(encoder, "{}:", username).unwrap();
+            if let Some(password) = password {
+                write!(encoder, "{}", password).unwrap();
+            }
+        }
+
+        self.header(crate::header::AUTHORIZATION, header_value)
+    }
+
     /// Enable HTTP bearer authentication.
     pub fn bearer_auth<T>(self, token: T) -> RequestBuilder
     where