diff --git a/src/nixcp.rs b/src/nixcp.rs
index a215923..f5b3dce 100644
--- a/src/nixcp.rs
+++ b/src/nixcp.rs
@@ -19,7 +19,7 @@ use url::Url;
 use crate::{Cli, path_info::PathInfo, uploader::Uploader};
 
 pub struct NixCp {
-    upstream_caches: Arc<Vec<Url>>,
+    upstream_caches: Vec<Url>,
     store_paths: Arc<RwLock<Vec<PathInfo>>>,
     s3_client: s3::Client,
     signing_key: SigningKey<ed25519_dalek::SigningKey>,
@@ -28,6 +28,8 @@ pub struct NixCp {
     signature_hit_count: AtomicUsize,
     // paths that we skipped cause we found it on an upstream
     upstream_hit_count: AtomicUsize,
+    // paths that we skipped cause they are already on our cache
+    already_exists_count: AtomicUsize,
 }
 
 impl NixCp {
@@ -58,13 +60,14 @@ impl NixCp {
 
         let s3_client = s3::Client::new(&s3_config.load().await);
         Ok(Self {
-            upstream_caches: Arc::new(upstreams),
+            upstream_caches: upstreams,
             store_paths: Arc::new(RwLock::new(Vec::new())),
             s3_client,
             signing_key,
             bucket: cli.bucket.clone(),
             signature_hit_count: AtomicUsize::new(0),
             upstream_hit_count: AtomicUsize::new(0),
+            already_exists_count: AtomicUsize::new(0),
         })
     }
 
@@ -86,7 +89,6 @@ impl NixCp {
 
     pub async fn run(&'static self) -> Result<()> {
         let (tx, rx) = mpsc::channel(10);
-        let tx = Arc::new(tx);
         let filter = tokio::spawn(self.filter_from_upstream(tx));
         let upload = tokio::spawn(self.upload(rx));
         filter.await?;
@@ -95,7 +97,7 @@ impl NixCp {
     }
 
     /// filter paths that are on upstream and send to `tx`
-    async fn filter_from_upstream(&'static self, tx: Arc<mpsc::Sender<PathInfo>>) {
+    async fn filter_from_upstream(&'static self, tx: mpsc::Sender<PathInfo>) {
         let permits = Arc::new(Semaphore::new(10));
         let mut handles = Vec::with_capacity(10);
         let store_paths = self.store_paths.read().await.clone();
@@ -109,12 +111,22 @@ impl NixCp {
             handles.push({
                 let permits = permits.clone();
                 let tx = tx.clone();
-                let upstream_caches = self.upstream_caches.clone();
                 tokio::spawn(async move {
                     let _permit = permits.acquire().await.unwrap();
 
-                    if !path.check_upstream_hit(upstream_caches.as_slice()).await {
-                        tx.send(path).await.unwrap();
+                    if !path
+                        .check_upstream_hit(self.upstream_caches.as_slice())
+                        .await
+                    {
+                        if path
+                            .check_if_already_exists(&self.s3_client, self.bucket.clone())
+                            .await
+                        {
+                            trace!("skip {} (already exists)", path.absolute_path());
+                            self.already_exists_count.fetch_add(1, Ordering::Relaxed);
+                        } else {
+                            tx.send(path).await.unwrap();
+                        }
                     } else {
                         trace!("skip {} (upstream hit)", path.absolute_path());
                         self.upstream_hit_count.fetch_add(1, Ordering::Relaxed);
@@ -169,6 +181,10 @@ impl NixCp {
                     "skipped because of upstream hit: {}",
                     self.upstream_hit_count.load(Ordering::Relaxed)
                 );
+                println!(
+                    "skipped because already exist: {}",
+                    self.already_exists_count.load(Ordering::Relaxed)
+                );
                 break;
             }
         }
diff --git a/src/path_info.rs b/src/path_info.rs
index 57e0a5b..2bf05ea 100644
--- a/src/path_info.rs
+++ b/src/path_info.rs
@@ -1,6 +1,7 @@
 use std::collections::HashSet;
 
 use anyhow::{Context, Error, Result};
+use aws_sdk_s3 as s3;
 use nix_compat::store_path::StorePath;
 use nix_compat::{nixbase32, nixhash::CAHash};
 use regex::Regex;
@@ -99,8 +100,9 @@ impl PathInfo {
     pub async fn check_upstream_hit(&self, upstreams: &[Url]) -> bool {
         for upstream in upstreams {
             let upstream = upstream
-                .join(format!("{}/.narinfo", self.digest()).as_str())
+                .join(format!("{}.narinfo", self.digest()).as_str())
                 .expect("adding <hash>.narinfo should make a valid url");
+            debug!("querying {}", upstream);
             let res_status = reqwest::Client::new()
                 .head(upstream.as_str())
                 .send()
@@ -121,6 +123,16 @@ impl PathInfo {
     pub fn digest(&self) -> String {
         nixbase32::encode(self.path.digest())
     }
+
+    pub async fn check_if_already_exists(&self, s3_client: &s3::Client, bucket: String) -> bool {
+        !s3_client
+            .head_object()
+            .bucket(bucket)
+            .key(format!("{}.narinfo", self.digest()))
+            .send()
+            .await
+            .is_err()
+    }
 }
 
 /*