diff --git a/supabase/functions/check-deposits/index.ts b/supabase/functions/check-deposits/index.ts
index 214edef..184199f 100644
--- a/supabase/functions/check-deposits/index.ts
+++ b/supabase/functions/check-deposits/index.ts
@@ -24,6 +24,20 @@ const TRC20_FEE = 3; // $3 fee for TRC20
 // API endpoints
 const TON_API = 'https://tonapi.io/v2';
 const TRON_API = 'https://api.trongrid.io';
+
+// Keyless TronGrid calls share a low public rate limit, so a missing key must
+// show up in the logs rather than go out as an empty header.
+let warnedNoTronKey = false;
+function tronHeaders(): Record<string, string> {
+  const key = Deno.env.get('TRONGRID_API_KEY');
+  if (key) return { 'TRON-PRO-API-KEY': key };
+  if (!warnedNoTronKey) {
+    console.warn('TRONGRID_API_KEY is not set; TronGrid calls are unauthenticated');
+    warnedNoTronKey = true;
+  }
+  return {};
+}
+
 const SUBSCAN_API = 'https://assethub-polkadot.api.subscan.io';
 
 // Contract addresses - raw format from TonAPI
@@ -274,7 +288,7 @@ async function checkTrc20Deposits(
     for (let i = 0; i < users.length; i += CONCURRENCY) {
       const batch = users.slice(i, i + CONCURRENCY);
       await Promise.all(
-        batch.map(async (user) => {
+        batch.map(async (user: { id: string; deposit_index: number }) => {
           try {
             const address = deriveTronAddress(hdMnemonic, user.deposit_index);
 
@@ -282,11 +296,14 @@ async function checkTrc20Deposits(
             const response = await fetch(
               `${TRON_API}/v1/accounts/${address}/transactions/trc20?limit=20&contract_address=${TRON_USDT_CONTRACT}`,
               {
-                headers: { 'TRON-PRO-API-KEY': Deno.env.get('TRONGRID_API_KEY') || '' },
+                headers: tronHeaders(),
               }
             );
 
-            if (!response.ok) return;
+            if (!response.ok) {
+              console.error(`TronGrid ${response.status} for deposit index ${user.deposit_index}`);
+              return;
+            }
 
             const data = await response.json();
             const transfers = data.data || [];
diff --git a/supabase/functions/process-deposits/index.ts b/supabase/functions/process-deposits/index.ts
index ef2db25..a4a449d 100644
--- a/supabase/functions/process-deposits/index.ts
+++ b/supabase/functions/process-deposits/index.ts
@@ -8,6 +8,20 @@ import { serve } from 'https://deno.land/std@0.177.0/http/server.ts';
 import { createClient } from 'https://esm.sh/@supabase/supabase-js@2';
 
 const TRON_API = 'https://api.trongrid.io';
+
+// Keyless TronGrid calls share a low public rate limit, so a missing key must
+// show up in the logs rather than go out as an empty header.
+let warnedNoTronKey = false;
+function tronHeaders(): Record<string, string> {
+  const key = Deno.env.get('TRONGRID_API_KEY');
+  if (key) return { 'TRON-PRO-API-KEY': key };
+  if (!warnedNoTronKey) {
+    console.warn('TRONGRID_API_KEY is not set; TronGrid calls are unauthenticated');
+    warnedNoTronKey = true;
+  }
+  return {};
+}
+
 const USDT_TRC20_CONTRACT = 'TR7NHqjeKQxGTCi8q8ZY4pL8otSzgjLj6t'; // USDT TRC20 contract
 
 interface TRC20Transfer {
@@ -78,7 +92,7 @@ serve(async (req) => {
       const response = await fetch(
         `${TRON_API}/v1/accounts/${tronAddress}/transactions/trc20?limit=50&contract_address=${USDT_TRC20_CONTRACT}`,
         {
-          headers: { 'TRON-PRO-API-KEY': Deno.env.get('TRONGRID_API_KEY') || '' },
+          headers: tronHeaders(),
         }
       );
 
@@ -125,6 +139,8 @@ serve(async (req) => {
             results.trc20.processed++;
           }
         }
+      } else {
+        results.trc20.errors.push(`TronGrid HTTP ${response.status}`);
       }
     } catch (err) {
       results.trc20.errors.push(`TRC20 error: ${err}`);