diff --git a/crates/switchyard-translation/src/helpers.rs b/crates/switchyard-translation/src/helpers.rs
index f1fc7c32..3be925cf 100644
--- a/crates/switchyard-translation/src/helpers.rs
+++ b/crates/switchyard-translation/src/helpers.rs
@@ -582,6 +582,17 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn decode_stream_accepts_sse_data_without_optional_space() -> Result<(), LlmClientError> {
+        let sse = b"data:{\"choices\":[{\"delta\":{\"content\":\"Hello\"}}]}\n\n\
+             data:[DONE]\n\n"
+            .to_vec();
+        let bytes = stream::once(async move { Ok::<Vec<u8>, LlmClientError>(sse) });
+        let chunks = decode_all(bytes, WireFormat::OpenAiChat)?;
+        assert_eq!(text_of(&chunks), "Hello");
+        Ok(())
+    }
+
     #[test]
     fn stream_helpers_replay_same_format_provider_fields() -> Result<(), BoxError> {
         let provider_event = json!({
diff --git a/crates/switchyard-translation/src/sse.rs b/crates/switchyard-translation/src/sse.rs
index dce5a361..08b8045a 100644
--- a/crates/switchyard-translation/src/sse.rs
+++ b/crates/switchyard-translation/src/sse.rs
@@ -36,7 +36,10 @@ pub(crate) fn parse_json_sse_frame(
     let data = frame
         .lines()
         .filter(|line| !line.is_empty() && !line.starts_with(':'))
-        .filter_map(|line| line.strip_prefix("data: ").map(|l| l.to_string()))
+        .filter_map(|line| {
+            line.strip_prefix("data:")
+                .map(|value| value.strip_prefix(' ').unwrap_or(value).to_string())
+        })
         .fold(String::new(), |mut a, b| {
             a.reserve(b.len() + 1);
             a.push_str(&b);