diff --git a/data/mesh.py b/data/mesh.py
index 9aaac2f..441bf60 100644
--- a/data/mesh.py
+++ b/data/mesh.py
@@ -157,6 +157,13 @@ def store_packet_dict(p: dict):
     from_id = _first(p, "fromId", "from_id", "from", default=None)
     to_id = _first(p, "toId", "to_id", "to", default=None)
 
+    if (from_id is None or str(from_id) == "") and DEBUG:
+        try:
+            raw = json.dumps(p, default=str)
+        except Exception:
+            raw = str(p)
+        print(f"[debug] packet missing from_id: {raw}")
+
     # link metrics
     snr = _first(p, "snr", "rx_snr", "rxSnr", default=None)
     rssi = _first(p, "rssi", "rx_rssi", "rxRssi", default=None)
diff --git a/web/app.rb b/web/app.rb
index 6ea3cc2..3837cd7 100644
--- a/web/app.rb
+++ b/web/app.rb
@@ -18,6 +18,7 @@ MAP_CENTER_LAT = ENV.fetch("MAP_CENTER_LAT", "52.502889").to_f
 MAP_CENTER_LON = ENV.fetch("MAP_CENTER_LON", "13.404194").to_f
 MAX_NODE_DISTANCE_KM = ENV.fetch("MAX_NODE_DISTANCE_KM", "137").to_f
 MATRIX_ROOM = ENV.fetch("MATRIX_ROOM", "#meshtastic-berlin:matrix.org")
+DEBUG = ENV["DEBUG"] == "1"
 
 def db_schema_present?
   return false unless File.exist?(DB_PATH)
@@ -91,6 +92,11 @@ def query_messages(limit)
                     SQL
   msg_fields = %w[id rx_time rx_iso from_id to_id channel portnum text msg_snr rssi hop_limit]
   rows.each do |r|
+    if DEBUG && (r["from_id"].nil? || r["from_id"].to_s.empty?)
+      raw = db.execute("SELECT * FROM messages WHERE id = ?", [r["id"]]).first
+      warn "[debug] messages row before join: #{raw.inspect}"
+      warn "[debug] row after join: #{r.inspect}"
+    end
     node = {}
     r.keys.each do |k|
       next if msg_fields.include?(k)
@@ -98,6 +104,9 @@ def query_messages(limit)
     end
     r["snr"] = r.delete("msg_snr")
     r["node"] = node unless node.empty?
+    if DEBUG && (r["from_id"].nil? || r["from_id"].to_s.empty?)
+      warn "[debug] row after processing: #{r.inspect}"
+    end
   end
   rows
 ensure