diff --git a/main.rb b/main.rb
index 61922fa..014e164 100644
--- a/main.rb
+++ b/main.rb
@@ -83,11 +83,27 @@ post '/video' do
   { status: 'ok' }.to_json
 end
 
+post '/check' do
+  content_type 'application/json'
+
+  ids = JSON.parse(request.body.read)
+
+  videos = Video
+    .left_outer_joins(:downloads)
+    .where(randname: ids)
+    .pluck(:randname, :sha256, :size)
+    .map { |v| %w[randname sha256 size].zip(v).to_h }
+
+  { videos: videos }.to_json
+end
+
+
 get '/config.json' do
   content_type 'application/json'
   {
     videos_url: "https://sapo.pxto.pt/videos.json",
     upload_url: "https://sapo.pxto.pt/video",
+    check_url: "https://sapo.pxto.pt/check",
     max_amount: 100_000,
   }.to_json
 end
diff --git a/saca-sapos b/saca-sapos
index cfd18b9..440ed0a 100755
--- a/saca-sapos
+++ b/saca-sapos
@@ -80,6 +80,20 @@ download() {
   fi
 }
 
+unknown() {
+  CONFIG="$(get_config)"
+  SAPO_CHECK_VIDEOS_URL="$(echo "$CONFIG" | jq -r .check_url)"
+
+  find videos/ -name "*.mp4" |
+    sed -e 's|videos/\(.*\).mp4|\1|g' |
+    xargs -n1000 |
+    sed -e 's/ /","/g' -e 's/^/["/' -e 's/$/"]/' |
+    while read body; do
+      echo "$body" | curl --silent --json "@-" "$SAPO_CHECK_VIDEOS_URL"
+    done |
+    jq -rc '.videos[]|select(.sha256==null)|("videos/" + .randname + ".mp4")'
+}
+
 case "$1" in
   "download")
     indexer "$2" "$3"
@@ -87,6 +101,9 @@ case "$1" in
   "single")
     download "$2"
     ;;
+  "unknown")
+    unknown
+    ;;
   "stats")
     BYTES="$(du -b videos/ | awk '{print $1}')"
     NUM="$(ls -1 videos/ | wc -l)"