diff --git a/crates/ruma-api-macros/src/api/request/outgoing.rs b/crates/ruma-api-macros/src/api/request/outgoing.rs
index f629b68a..380906b3 100644
--- a/crates/ruma-api-macros/src/api/request/outgoing.rs
+++ b/crates/ruma-api-macros/src/api/request/outgoing.rs
@@ -226,11 +226,9 @@ impl Request {
                             "application/json",
                         );
 
-                    let mut req_headers = req_builder
-                        .headers_mut()
-                        .expect("`http::RequestBuilder` is in unusable state");
-
-                    #header_kvs
+                    if let Some(mut req_headers) = req_builder.headers_mut() {
+                        #header_kvs
+                    }
 
                     let http_request = req_builder.body(#request_body)?;
 
diff --git a/crates/ruma-api/CHANGELOG.md b/crates/ruma-api/CHANGELOG.md
index 7d0b6286..b598b4e8 100644
--- a/crates/ruma-api/CHANGELOG.md
+++ b/crates/ruma-api/CHANGELOG.md
@@ -21,6 +21,10 @@ Improvements:
 * Add a new `MatrixError` type to the `error` module that consists of a HTTP status code and JSON
   `body` and is the new default error type for `ruma_api!`
 
+Bug fixes:
+
+* Prevent panic when building requests with an invalid URI  
+
 # 0.16.1
 
 Bug fixes:
diff --git a/crates/ruma-api/tests/conversions.rs b/crates/ruma-api/tests/conversions.rs
index fc21e0e2..2f9e03e6 100644
--- a/crates/ruma-api/tests/conversions.rs
+++ b/crates/ruma-api/tests/conversions.rs
@@ -62,6 +62,21 @@ fn request_serde() {
     assert_eq!(req.user, req2.user);
 }
 
+#[test]
+fn invalid_uri_should_not_panic() {
+    let req = Request {
+        hello: "hi".to_owned(),
+        world: "test".to_owned(),
+        q1: "query_param_special_chars %/&@!".to_owned(),
+        q2: 55,
+        bar: "barVal".to_owned(),
+        user: user_id!("@bazme:ruma.io"),
+    };
+
+    let result = req.clone().try_into_http_request::<Vec<u8>>("invalid uri", SendAccessToken::None);
+    assert!(result.is_err());
+}
+
 #[test]
 fn request_with_user_id_serde() {
     let req = Request {