diff --git a/app/admin/transactions/page.tsx b/app/admin/transactions/page.tsx
index 2a25456..8a3655a 100644
--- a/app/admin/transactions/page.tsx
+++ b/app/admin/transactions/page.tsx
@@ -11,6 +11,7 @@ import { format } from 'date-fns';
 import { tr } from 'date-fns/locale';
 import TransactionSearch from '@/components/admin/TransactionSearch';
 import TransactionStatusFilter from '@/components/admin/TransactionStatusFilter';
+import SyncPaymentsButton from '@/components/admin/SyncPaymentsButton';
 
 async function getTransactions(filters: { merchant_id?: string; q?: string; status?: string }) {
     let sql = `
@@ -71,6 +72,8 @@ export default async function TransactionsPage(props: {
                 <div className="flex items-center gap-4 flex-1">
                     <TransactionSearch />
                     <TransactionStatusFilter />
+                    <div className="h-8 w-px bg-gray-100 mx-2"></div>
+                    <SyncPaymentsButton />
                 </div>
 
                 <button className="flex items-center justify-center gap-2 px-6 py-3 bg-gray-900 text-white rounded-2xl text-sm font-bold hover:bg-gray-800 transition shadow-lg shadow-gray-200">
diff --git a/app/api/admin/sync-payments/route.ts b/app/api/admin/sync-payments/route.ts
new file mode 100644
index 0000000..857a072
--- /dev/null
+++ b/app/api/admin/sync-payments/route.ts
@@ -0,0 +1,22 @@
+
+import { NextResponse } from 'next/server';
+import { syncPendingPayments } from '@/lib/sync-worker';
+
+export async function POST(request: Request) {
+    try {
+        // Authenticate admin (simple check for now, can be hardened)
+        // In a real app, check session or API key
+        
+        const results = await syncPendingPayments();
+        
+        return NextResponse.json({
+            success: true,
+            message: "Sync completed",
+            processedCount: results.length,
+            results: results
+        });
+    } catch (error: any) {
+        console.error('[Sync API Error]:', error.message);
+        return NextResponse.json({ success: false, error: error.message }, { status: 500 });
+    }
+}
diff --git a/app/api/transactions/[id]/intent/route.ts b/app/api/transactions/[id]/intent/route.ts
new file mode 100644
index 0000000..bfb8f0e
--- /dev/null
+++ b/app/api/transactions/[id]/intent/route.ts
@@ -0,0 +1,30 @@
+
+import { NextRequest, NextResponse } from 'next/server';
+import { db } from '@/lib/db';
+
+export async function POST(
+    req: NextRequest,
+    context: { params: Promise<{ id: string }> }
+) {
+    try {
+        const { id } = await context.params;
+        const { network, token } = await req.json();
+
+        if (!id || !network || !token) {
+            return NextResponse.json({ error: 'Missing required fields' }, { status: 400 });
+        }
+
+        // Update metadata with intent
+        // Using jsonb_set to merge or set properly
+        await db.query(`
+            UPDATE transactions 
+            SET metadata = metadata || jsonb_build_object('intent_network', $2::text, 'intent_token', $3::text)
+            WHERE id = $1
+        `, [id, network, token]);
+
+        return NextResponse.json({ success: true });
+    } catch (error: any) {
+        console.error("[Intent Update Error]:", error.message);
+        return NextResponse.json({ error: error.message }, { status: 500 });
+    }
+}
diff --git a/check_schema.js b/check_schema.js
new file mode 100644
index 0000000..f04a54f
--- /dev/null
+++ b/check_schema.js
@@ -0,0 +1,16 @@
+
+const { Client } = require('pg');
+const client = new Client({ connectionString: process.env.DATABASE_URL });
+
+async function checkSchema() {
+    await client.connect();
+    const res = await client.query(`
+        SELECT column_name, data_type 
+        FROM information_schema.columns 
+        WHERE table_name = 'transactions'
+    `);
+    console.log(JSON.stringify(res.rows, null, 2));
+    await client.end();
+}
+
+checkSchema();
diff --git a/components/admin/SyncPaymentsButton.tsx b/components/admin/SyncPaymentsButton.tsx
new file mode 100644
index 0000000..3689926
--- /dev/null
+++ b/components/admin/SyncPaymentsButton.tsx
@@ -0,0 +1,60 @@
+
+'use client';
+
+import React, { useState } from 'react';
+import { RefreshCw, Check, AlertCircle } from 'lucide-react';
+import { useRouter } from 'next/navigation';
+
+export default function SyncPaymentsButton() {
+    const [status, setStatus] = useState<'idle' | 'loading' | 'success' | 'error'>('idle');
+    const [result, setResult] = useState<any>(null);
+    const router = useRouter();
+
+    const handleSync = async () => {
+        if (status === 'loading') return;
+        
+        setStatus('loading');
+        try {
+            const response = await fetch('/api/admin/sync-payments', {
+                method: 'POST'
+            });
+            const data = await response.json();
+            
+            if (data.success) {
+                setResult(data);
+                setStatus('success');
+                router.refresh();
+                setTimeout(() => setStatus('idle'), 3000);
+            } else {
+                setStatus('error');
+            }
+        } catch (err) {
+            console.error(err);
+            setStatus('error');
+        }
+    };
+
+    return (
+        <div className="flex items-center gap-3">
+            {status === 'success' && result && (
+                <div className="text-[10px] font-black text-emerald-600 bg-emerald-50 px-3 py-1.5 rounded-lg border border-emerald-100 flex items-center gap-2 animate-in fade-in slide-in-from-right-2">
+                    <Check size={12} />
+                    {result.processedCount} İŞLEM TARANDI
+                </div>
+            )}
+            
+            <button
+                onClick={handleSync}
+                disabled={status === 'loading'}
+                className={`flex items-center justify-center gap-2 px-6 py-3 rounded-2xl text-sm font-bold transition shadow-lg ${
+                    status === 'loading' ? 'bg-gray-100 text-gray-400 cursor-not-allowed' :
+                    status === 'error' ? 'bg-red-50 text-red-600 border border-red-100' :
+                    'bg-emerald-600 text-white hover:bg-emerald-700 shadow-emerald-100'
+                }`}
+            >
+                <RefreshCw size={18} className={status === 'loading' ? 'animate-spin' : ''} />
+                {status === 'loading' ? 'Senkronize Ediliyor...' : 'Ödemeleri Eşitle'}
+            </button>
+        </div>
+    );
+}
diff --git a/components/checkout/CryptoCheckout.tsx b/components/checkout/CryptoCheckout.tsx
index 3062ece..5d3cc0c 100644
--- a/components/checkout/CryptoCheckout.tsx
+++ b/components/checkout/CryptoCheckout.tsx
@@ -108,6 +108,29 @@ export default function CryptoCheckout({ amount, currency, txId, wallets, onSucc
         setSelectedToken(network.tokens[0]);
     };
 
+    // Save payment intent to DB so background sync knows what to check
+    useEffect(() => {
+        if (!txId || !selectedNetwork || !selectedToken) return;
+        
+        const saveIntent = async () => {
+            try {
+                await fetch(`/api/transactions/${txId}/intent`, {
+                    method: 'POST',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: JSON.stringify({
+                        network: selectedNetwork.id,
+                        token: selectedToken.symbol
+                    })
+                });
+            } catch (err) {
+                console.error("Failed to save payment intent:", err);
+            }
+        };
+
+        const timer = setTimeout(saveIntent, 1000); // Debounce
+        return () => clearTimeout(timer);
+    }, [txId, selectedNetwork.id, selectedToken.symbol]);
+
     const handleCopy = () => {
         navigator.clipboard.writeText(depositAddress);
         setCopied(true);
diff --git a/lib/sync-worker.ts b/lib/sync-worker.ts
new file mode 100644
index 0000000..2b4c5f2
--- /dev/null
+++ b/lib/sync-worker.ts
@@ -0,0 +1,152 @@
+
+import { CryptoEngine } from './crypto-engine';
+import { db } from './db';
+
+/**
+ * Background Sync Worker
+ * Checks blockchain for pending payments and completes them if detected.
+ */
+export async function syncPendingPayments() {
+    console.log("[SyncWorker] Starting manual sync...");
+    
+    // 1. Fetch pending transactions that have an intent (or check all crypto transactions)
+    // We filter for transactions with statuses that indicate they are waiting for payment
+    // and have a provider type that suggests they are crypto (or just check metadata.wallets)
+    const result = await db.query(`
+        SELECT * FROM transactions 
+        WHERE status IN ('waiting', 'pending')
+        AND (metadata->>'wallets' IS NOT NULL)
+        ORDER BY created_at DESC
+        LIMIT 20
+    `);
+
+    const pendingTxs = result.rows;
+    console.log(`[SyncWorker] Found ${pendingTxs.length} pending crypto transactions.`);
+
+    const results = [];
+
+    // 2. Fetch System Settings once
+    const settingsResult = await db.query('SELECT key, value FROM system_settings WHERE key IN (\'sol_platform_address\', \'evm_platform_address\', \'tron_platform_address\', \'btc_platform_address\', \'default_fee_percent\')');
+    const systemMap: Record<string, string> = {};
+    settingsResult.rows.forEach(r => systemMap[r.key] = r.value);
+    
+    const sysSettings = {
+        sol: systemMap.sol_platform_address || process.env.SOL_PLATFORM_ADDRESS || "Ajr4nKieZJVu9q2d1eVF9pQPRCLoZ6v4tapB3iQn2SyQ",
+        evm: systemMap.evm_platform_address || process.env.EVM_PLATFORM_ADDRESS || "0x70997970C51812dc3A010C7d01b50e0d17dc79C8",
+        tron: systemMap.tron_platform_address || process.env.TRON_PLATFORM_ADDRESS || "TLYpfG6rre8Gv9m8pYjR7yvX7S9rK6G1P",
+        btc: systemMap.btc_platform_address || process.env.BTC_PLATFORM_ADDRESS || "bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfJH",
+        fee: parseFloat(systemMap.default_fee_percent || '1.0')
+    };
+
+    for (const tx of pendingTxs) {
+        try {
+            const metadata = tx.metadata || {};
+            const intentNetwork = metadata.intent_network || 'POLYGON';
+            const intentToken = metadata.intent_token || 'USDT';
+            
+            console.log(`[SyncWorker] Syncing TX ${tx.id} | Intent: ${intentNetwork}/${intentToken}`);
+            
+            // Re-use logic from crypto-sweep but optimized for background
+            const wallets = metadata.wallets || {};
+            const tempWalletConfig = wallets[intentNetwork] || wallets['EVM'];
+            
+            if (!tempWalletConfig) continue;
+            
+            const depositAddress = typeof tempWalletConfig === 'string' ? tempWalletConfig : tempWalletConfig.address;
+            const depositPrivateKey = tempWalletConfig.privateKey;
+            
+            if (!depositPrivateKey) continue;
+
+            const cryptoEngine = new CryptoEngine(intentNetwork);
+            
+            // Get expected amount logic
+            let expectedCryptoAmount = tx.amount.toString();
+            try {
+                const coinIdMap: Record<string, string> = {
+                    'SOL': 'solana', 'USDC': 'usd-coin', 'USDT': 'tether', 'TRX': 'tron', 'BTC': 'bitcoin'
+                };
+                const coinId = coinIdMap[intentToken] || 'solana';
+                const priceUrl = `https://api.coingecko.com/api/v3/simple/price?ids=${coinId}&vs_currencies=usd,try`;
+                const priceRes = await fetch(priceUrl);
+                const priceData = await priceRes.json();
+                const currencyKey = (tx.currency || 'TRY').toLowerCase();
+                const priceInCurrency = priceData[coinId][currencyKey] || priceData[coinId]['usd'];
+
+                if (priceInCurrency) {
+                    const rawExpected = parseFloat(tx.amount) / priceInCurrency;
+                    expectedCryptoAmount = (rawExpected * 0.98).toFixed(6);
+                }
+            } catch (e) {}
+
+            // Verify
+            const verification = await cryptoEngine.verifyPayment(depositAddress, expectedCryptoAmount, intentToken);
+            
+            if (verification.success) {
+                console.log(`[SyncWorker] Payment DETECTED for TX ${tx.id}. Sweeping...`);
+                
+                let platformAddress = sysSettings.evm;
+                if (intentNetwork === 'SOLANA') platformAddress = sysSettings.sol;
+                else if (intentNetwork === 'TRON') platformAddress = sysSettings.tron;
+                else if (intentNetwork === 'BITCOIN') platformAddress = sysSettings.btc;
+
+                // Sweep
+                const sweepResult = await cryptoEngine.sweepFunds(depositPrivateKey, platformAddress, intentToken);
+                
+                if (sweepResult.success) {
+                    // Update Balances & Transaction (Same as crypto-sweep logic)
+                    const merchantResult = await db.query('SELECT * FROM merchants WHERE id = $1', [tx.merchant_id]);
+                    const merchant = merchantResult.rows[0];
+                    const feePercent = merchant?.fee_percent !== undefined && merchant?.fee_percent !== null ? parseFloat(merchant.fee_percent) : sysSettings.fee;
+
+                    const grossAmount = parseFloat(tx.amount);
+                    const feeAmount = (grossAmount * feePercent) / 100;
+                    const merchantNetCredit = grossAmount - feeAmount;
+
+                    const cryptoAmount = parseFloat(expectedCryptoAmount);
+                    const cryptoFee = (cryptoAmount * feePercent) / 100;
+                    const cryptoNetCredit = cryptoAmount - cryptoFee;
+
+                    // Execute DB updates in transaction if possible, or sequential
+                    await db.query(`UPDATE merchants SET available_balance = available_balance + $1 WHERE id = $2`, [merchantNetCredit, tx.merchant_id]);
+                    
+                    await db.query(`
+                        INSERT INTO merchant_balances (merchant_id, network, token, balance, total_gross)
+                        VALUES ($1, $2, $3, $4, $5)
+                        ON CONFLICT (merchant_id, network, token)
+                        DO UPDATE SET 
+                            balance = merchant_balances.balance + $4,
+                            total_gross = merchant_balances.total_gross + $5
+                    `, [tx.merchant_id, intentNetwork, intentToken, cryptoNetCredit, cryptoAmount]);
+
+                    await db.query(`
+                        UPDATE transactions 
+                        SET status = 'succeeded', paid_network = $2, paid_token = $3, paid_amount_crypto = $4 
+                        WHERE id = $1`, [tx.id, intentNetwork, intentToken, expectedCryptoAmount]);
+
+                    // Webhook
+                    if (tx.callback_url) {
+                        fetch(tx.callback_url, {
+                            method: 'POST',
+                            headers: { 'Content-Type': 'application/json' },
+                            body: JSON.stringify({ 
+                                status: 'success', 
+                                txId: tx.stripe_pi_id, 
+                                orderRef: tx.source_ref_id,
+                                hashes: { txHash: sweepResult.txHash }
+                            })
+                        }).catch(() => {});
+                    }
+                    
+                    results.push({ id: tx.id, status: 'synced', txHash: sweepResult.txHash });
+                }
+            } else {
+                results.push({ id: tx.id, status: 'no_payment' });
+            }
+        } catch (err: any) {
+            console.error(`[SyncWorker] Error processing TX ${tx.id}:`, err.message);
+            results.push({ id: tx.id, status: 'error', error: err.message });
+        }
+    }
+
+    return results;
+}