diff --git a/ui/frontend/reducers/output/format.ts b/ui/frontend/reducers/output/format.ts
index e03a550d8..d16f92e5d 100644
--- a/ui/frontend/reducers/output/format.ts
+++ b/ui/frontend/reducers/output/format.ts
@@ -18,8 +18,9 @@ interface State {
 }
 
 interface FormatRequestBody {
-  code: string;
+  channel: string;
   edition: string;
+  code: string;
 }
 
 const FormatResponseBody = z.object({
diff --git a/ui/frontend/selectors/index.ts b/ui/frontend/selectors/index.ts
index c63cd02cb..3e9a20492 100644
--- a/ui/frontend/selectors/index.ts
+++ b/ui/frontend/selectors/index.ts
@@ -99,10 +99,27 @@ const LABELS: { [index in PrimaryActionCore]: string } = {
 
 export const getExecutionLabel = createSelector(primaryActionSelector, primaryAction => LABELS[primaryAction]);
 
+const channelSelector = (state: State) => state.configuration.channel;
+
+const selectedChannelVersionsSelector = createSelector(
+  channelSelector,
+  (state: State) => state.versions,
+  (channel, versions) => {
+    switch (channel) {
+      case Channel.Stable:
+        return versions.stable;
+      case Channel.Beta:
+        return versions.beta;
+      case Channel.Nightly:
+        return versions.nightly;
+    }
+  },
+)
+
 const getStable = (state: State) => state.versions.stable?.rustc;
 const getBeta = (state: State) => state.versions.beta?.rustc;
 const getNightly = (state: State) => state.versions.nightly?.rustc;
-const getRustfmt = (state: State) => state.versions.nightly?.rustfmt;
+const getRustfmt = createSelector(selectedChannelVersionsSelector, (versions) => versions?.rustfmt);
 const getClippy = (state: State) => state.versions.nightly?.clippy;
 const getMiri = (state: State) => state.versions?.nightly?.miri;
 
@@ -123,8 +140,6 @@ export const miriVersionDetailsText = createSelector(getMiri, versionDetails);
 
 const editionSelector = (state: State) => state.configuration.edition;
 
-const channelSelector = (state: State) => state.configuration.channel;
-
 export const isNightlyChannel = createSelector(
   channelSelector,
   (channel) => channel === Channel.Nightly,
@@ -311,9 +326,10 @@ export const clippyRequestSelector = createSelector(
 );
 
 export const formatRequestSelector = createSelector(
-  codeSelector,
+  channelSelector,
   editionSelector,
-  (code, edition) => ({ code, edition }),
+  codeSelector,
+  (channel, edition, code) => ({ channel, edition, code }),
 );
 
 const focus = (state: State) => state.output.meta.focus;
diff --git a/ui/src/main.rs b/ui/src/main.rs
index 184765b3a..f00a97d8d 100644
--- a/ui/src/main.rs
+++ b/ui/src/main.rs
@@ -355,9 +355,11 @@ struct ExecuteResponse {
 
 #[derive(Debug, Clone, Deserialize)]
 struct FormatRequest {
-    code: String,
+    #[serde(default)]
+    channel: Option<String>,
     #[serde(default)]
     edition: String,
+    code: String,
 }
 
 #[derive(Debug, Clone, Serialize)]
diff --git a/ui/src/server_axum.rs b/ui/src/server_axum.rs
index 1341a4570..d01e7a9eb 100644
--- a/ui/src/server_axum.rs
+++ b/ui/src/server_axum.rs
@@ -1052,10 +1052,19 @@ pub(crate) mod api_orchestrator_integration_impls {
         type Error = ParseFormatRequestError;
 
         fn try_from(other: crate::FormatRequest) -> std::result::Result<Self, Self::Error> {
-            let crate::FormatRequest { code, edition } = other;
+            let crate::FormatRequest {
+                channel,
+                edition,
+                code,
+            } = other;
+
+            let channel = match channel {
+                Some(c) => parse_channel(&c)?,
+                None => Channel::Nightly,
+            };
 
             Ok(FormatRequest {
-                channel: Channel::Nightly,     // TODO: use what user has submitted
+                channel,
                 crate_type: CrateType::Binary, // TODO: use what user has submitted
                 edition: parse_edition(&edition)?,
                 code,
@@ -1065,6 +1074,9 @@ pub(crate) mod api_orchestrator_integration_impls {
 
     #[derive(Debug, Snafu)]
     pub(crate) enum ParseFormatRequestError {
+        #[snafu(context(false))]
+        Channel { source: ParseChannelError },
+
         #[snafu(context(false))]
         Edition { source: ParseEditionError },
     }