diff --git a/core/services/s3/src/backend.rs b/core/services/s3/src/backend.rs
index f6002d5a2857..ab6c2dd73b31 100644
--- a/core/services/s3/src/backend.rs
+++ b/core/services/s3/src/backend.rs
@@ -721,10 +721,8 @@ impl S3Builder {
     }
 }
 
-impl Builder for S3Builder {
-    type Config = S3Config;
-
-    fn build(self) -> Result<impl Service> {
+impl S3Builder {
+    fn build_backend(self) -> Result<S3Backend> {
         debug!("backend build started: {:?}", &self);
 
         let S3Builder {
@@ -1032,6 +1030,14 @@ impl Builder for S3Builder {
     }
 }
 
+impl Builder for S3Builder {
+    type Config = S3Config;
+
+    fn build(self) -> Result<impl Service> {
+        self.build_backend()
+    }
+}
+
 /// Backend for s3 services.
 #[derive(Debug, Clone)]
 pub struct S3Backend {
@@ -1359,4 +1365,33 @@ mod tests {
             "application/json"
         );
     }
+
+    #[test]
+    fn test_s3_copy_object_request_sets_content_length_zero() -> Result<()> {
+        let backend = S3Builder::default()
+            .bucket("test")
+            .region("us-east-1")
+            .skip_signature()
+            .disable_config_load()
+            .disable_ec2_metadata()
+            .build_backend()?;
+
+        let req = backend
+            .core
+            .s3_copy_object_request("from.txt", "to.txt", &OpCopy::default())?;
+
+        assert_eq!(req.method(), http::Method::PUT);
+        assert!(req.uri().to_string().ends_with("/test/to.txt"));
+        assert_eq!(
+            req.headers().get(http::header::CONTENT_LENGTH).unwrap(),
+            "0"
+        );
+        assert_eq!(
+            req.headers().get(constants::X_AMZ_COPY_SOURCE).unwrap(),
+            "test/from.txt"
+        );
+        assert!(req.body().is_empty());
+
+        Ok(())
+    }
 }
diff --git a/core/services/s3/src/core.rs b/core/services/s3/src/core.rs
index a66d204eebf8..65673f6a58d6 100644
--- a/core/services/s3/src/core.rs
+++ b/core/services/s3/src/core.rs
@@ -690,13 +690,12 @@ impl S3Core {
         self.send(ctx, req).await
     }
 
-    pub async fn s3_copy_object(
+    pub fn s3_copy_object_request(
         &self,
-        ctx: &OperationContext,
         from: &str,
         to: &str,
         args: &OpCopy,
-    ) -> Result<Response<Buffer>> {
+    ) -> Result<Request<Buffer>> {
         let from = build_abs_path(&self.root, from);
         let to = build_abs_path(&self.root, to);
 
@@ -769,10 +768,24 @@ impl S3Core {
             // Inject operation to the request.
             .extension(Operation::Copy)
             .extension(ServiceOperation("CopyObject"))
+            // AWS S3 doesn't care, but some other S3-compat providers
+            // require a mandatory `content-length` header to work
+            .header(CONTENT_LENGTH, 0)
             .header(constants::X_AMZ_COPY_SOURCE, &source)
             .body(Buffer::new())
             .map_err(new_request_build_error)?;
 
+        Ok(req)
+    }
+
+    pub async fn s3_copy_object(
+        &self,
+        ctx: &OperationContext,
+        from: &str,
+        to: &str,
+        args: &OpCopy,
+    ) -> Result<Response<Buffer>> {
+        let req = self.s3_copy_object_request(from, to, args)?;
         self.send(ctx, req).await
     }