diff --git a/crates/ragfs/src/plugins/queuefs/backend.rs b/crates/ragfs/src/plugins/queuefs/backend.rs
index 72e13b9d6..8ee7302db 100644
--- a/crates/ragfs/src/plugins/queuefs/backend.rs
+++ b/crates/ragfs/src/plugins/queuefs/backend.rs
@@ -6,7 +6,7 @@
 use crate::core::errors::{Error, Result};
 use chrono::{DateTime, Utc};
 use rusqlite::{params, types::ValueRef, Connection, Row};
-use serde::{Deserialize, Serialize};
+use serde::{Deserialize, Deserializer, Serialize};
 use std::collections::{HashMap, VecDeque};
 use std::sync::Mutex;
 use std::time::{Duration, UNIX_EPOCH};
@@ -39,7 +39,8 @@ impl Message {
 #[derive(Debug, Clone, Serialize, Deserialize)]
 struct StoredMessage {
     id: String,
-    data: String,
+    #[serde(deserialize_with = "deserialize_stored_message_data")]
+    data: Vec<u8>,
     #[serde(default)]
     timestamp: Option<serde_json::Value>,
 }
@@ -48,7 +49,7 @@ impl StoredMessage {
     fn from_message(msg: &Message) -> Self {
         Self {
             id: msg.id.clone(),
-            data: String::from_utf8_lossy(&msg.data).to_string(),
+            data: msg.data.clone(),
             // Prefer unix seconds for compatibility with older queue.db producers.
             timestamp: Some(serde_json::Value::Number(unix_secs(msg.timestamp).into())),
         }
@@ -57,12 +58,41 @@ impl StoredMessage {
     fn into_message(self) -> Message {
         Message {
             id: self.id,
-            data: self.data.into_bytes(),
+            data: self.data,
             timestamp: parse_stored_timestamp(self.timestamp),
         }
     }
 }
 
+fn deserialize_stored_message_data<'de, D>(
+    deserializer: D,
+) -> std::result::Result<Vec<u8>, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    let value = serde_json::Value::deserialize(deserializer)?;
+    match value {
+        // Legacy queue.db rows stored message bytes as a JSON string.
+        serde_json::Value::String(data) => Ok(data.into_bytes()),
+        // New rows keep arbitrary message bytes lossless as a JSON byte array.
+        serde_json::Value::Array(bytes) => bytes
+            .into_iter()
+            .map(|byte| {
+                byte.as_u64()
+                    .and_then(|value| u8::try_from(value).ok())
+                    .ok_or_else(|| {
+                        serde::de::Error::custom(
+                            "stored queue message data byte must be an integer in 0..=255",
+                        )
+                    })
+            })
+            .collect(),
+        other => Err(serde::de::Error::custom(format!(
+            "stored queue message data must be a string or byte array, got {other}"
+        ))),
+    }
+}
+
 fn parse_stored_timestamp(raw: Option<serde_json::Value>) -> SystemTime {
     match raw {
         Some(serde_json::Value::String(ts)) => DateTime::parse_from_rfc3339(&ts)
@@ -846,6 +876,25 @@ mod tests {
         assert_eq!(second.data, b"message 2");
     }
 
+    #[test]
+    fn test_sqlite_backend_preserves_non_utf8_payload_bytes() {
+        let dir = tempdir().unwrap();
+        let db_path = dir.path().join("queue.db");
+        let mut backend =
+            SQLiteQueueBackend::open(db_path.to_str().unwrap(), SQLiteQueueOptions::default())
+                .unwrap();
+
+        backend.create_queue("test").unwrap();
+        let payload = vec![0xff, 0x00, 0x80, b'a'];
+        backend.enqueue("test", Message::new(payload.clone())).unwrap();
+
+        let peeked = backend.peek("test").unwrap().unwrap();
+        assert_eq!(peeked.data, payload);
+
+        let dequeued = backend.dequeue("test").unwrap().unwrap();
+        assert_eq!(dequeued.data, payload);
+    }
+
     #[test]
     fn test_sqlite_backend_recover_stale() {
         let dir = tempdir().unwrap();