diff --git a/.dockerignore b/.dockerignore
index e37db74..cca5f06 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -5,3 +5,4 @@ dist
 .gitignore
 *.log
 README.md
+swagger.yaml
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index aa0926a..f83b229 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@ node_modules/
 dist/
 .env
 *.log
+swagger.yaml
\ No newline at end of file
diff --git a/src/db/PostgresClient.ts b/src/db/PostgresClient.ts
index a26b2c3..4f73b21 100644
--- a/src/db/PostgresClient.ts
+++ b/src/db/PostgresClient.ts
@@ -1,13 +1,14 @@
-import pg from "pg";
-import type { DatabaseSecret } from "../secrets/VaultClient.js";
+import pg from 'pg';
+import type {DatabaseSecret} from '../secrets/VaultClient.js';
 
 const { Pool } = pg;
 
 export type PaymentStatus =
-  | "pending"
-  | "usdt_delivered"
-  | "web3_hash_error"
-  | "web3_balance_problem"
+  | 'pending'
+  | 'web3_processing'
+  | 'usdt_delivered'
+  | 'web3_hash_error'
+  | 'web3_balance_problem'
   | string;
 
 export interface PaymentRecord {
@@ -15,6 +16,11 @@ export interface PaymentRecord {
   web3_transaction_hash: string | null;
 }
 
+export interface PaymentClaimResult {
+  claimed: boolean;
+  payment: PaymentRecord | null;
+}
+
 export class PostgresClient {
   private readonly pool: pg.Pool;
 
@@ -32,12 +38,12 @@ export class PostgresClient {
   }
 
   async ping(): Promise<void> {
-    await this.pool.query("SELECT 1");
+    await this.pool.query('SELECT 1');
   }
 
   async getOrderUsdtAmount(orderId: string): Promise<string | null> {
     const result = await this.pool.query<{ usdt_amount: string }>(
-      "SELECT usdt_amount::text AS usdt_amount FROM orders WHERE id = $1",
+      'SELECT usdt_amount::text AS usdt_amount FROM orders WHERE id = $1',
       [orderId]
     );
     return result.rows[0]?.usdt_amount ?? null;
@@ -45,7 +51,7 @@ export class PostgresClient {
 
   async getUserEthWalletAddress(userId: string): Promise<string | null> {
     const result = await this.pool.query<{ address: string }>(
-      "SELECT address FROM wallets WHERE user_id = $1 AND chain = 'ETH' LIMIT 1",
+      `SELECT address FROM wallets WHERE user_id = $1 AND chain = 'ETH' LIMIT 1`,
       [userId]
     );
     return result.rows[0]?.address ?? null;
@@ -53,15 +59,44 @@ export class PostgresClient {
 
   async getPaymentByOrderId(orderId: string): Promise<PaymentRecord | null> {
     const result = await this.pool.query<PaymentRecord>(
-      "SELECT status, web3_transaction_hash FROM payments WHERE order_id = $1",
+      'SELECT status, web3_transaction_hash FROM payments WHERE order_id = $1',
       [orderId]
     );
     return result.rows[0] ?? null;
   }
 
+  async claimPaymentForTransfer(orderId: string): Promise<PaymentClaimResult> {
+    const claimed = await this.pool.query<PaymentRecord>(
+      `UPDATE payments
+         SET status = 'web3_processing',
+             updated_at = now()
+       WHERE order_id = $1
+         AND web3_transaction_hash IS NULL
+         AND status NOT IN ('web3_processing', 'usdt_delivered', 'web3_hash_error', 'web3_balance_problem')
+       RETURNING status, web3_transaction_hash`,
+      [orderId]
+    );
+
+    if (claimed.rows[0]) {
+      return {
+        claimed: true,
+        payment: claimed.rows[0]
+      };
+    }
+
+    return {
+      claimed: false,
+      payment: await this.getPaymentByOrderId(orderId)
+    };
+  }
+
   async setPaymentTxHash(orderId: string, txHash: string): Promise<void> {
     await this.pool.query(
-      "UPDATE payments SET web3_transaction_hash = $2, updated_at = now() WHERE order_id = $1",
+      `UPDATE payments
+         SET web3_transaction_hash = $2,
+             updated_at = now()
+       WHERE order_id = $1
+         AND status = 'web3_processing'`,
       [orderId, txHash]
     );
   }
@@ -73,14 +108,19 @@ export class PostgresClient {
              web3_transaction_hash = $2,
              paid_at = now(),
              updated_at = now()
-       WHERE order_id = $1`,
+       WHERE order_id = $1
+         AND status = 'web3_processing'`,
       [orderId, txHash]
     );
   }
 
   async markPaymentHashError(orderId: string): Promise<void> {
     await this.pool.query(
-      "UPDATE payments SET status = 'web3_hash_error', updated_at = now() WHERE order_id = $1",
+      `UPDATE payments
+         SET status = 'web3_hash_error',
+             updated_at = now()
+       WHERE order_id = $1
+         AND status = 'web3_processing'`,
       [orderId]
     );
   }
@@ -91,7 +131,8 @@ export class PostgresClient {
          SET status = 'web3_balance_problem',
              web3_transaction_hash = $2,
              updated_at = now()
-       WHERE order_id = $1`,
+       WHERE order_id = $1
+         AND status = 'web3_processing'`,
       [orderId, txHash]
     );
   }
diff --git a/src/services/TransferOrchestrator.ts b/src/services/TransferOrchestrator.ts
index a680bca..0c670ce 100644
--- a/src/services/TransferOrchestrator.ts
+++ b/src/services/TransferOrchestrator.ts
@@ -28,23 +28,15 @@ export class TransferOrchestrator {
   }
 
   async handle(message: CryptoTransferRequest, log: Logger): Promise<void> {
-    const existing = await this.db.getPaymentByOrderId(message.order_id);
+    const claim = await this.db.claimPaymentForTransfer(message.order_id);
+    const existing = claim.payment;
     if (!existing) {
       log.error({ event: 'payment.missing' }, 'no payment row for order_id, ack');
       return;
     }
 
-    if (existing.status === 'usdt_delivered') {
-      log.info({ event: 'payment.already_delivered' }, 'already delivered, publishing completion');
-      await this.publishCompleted(message, log);
-      return;
-    }
-
-    if (existing.status === 'web3_hash_error' || existing.status === 'web3_balance_problem') {
-      log.warn(
-        { event: 'payment.terminal_state', status: existing.status },
-        'skip - payment already in terminal failure state'
-      );
+    if (!claim.claimed) {
+      await this.handleAlreadyClaimed(message, existing, log);
       return;
     }
 
@@ -198,6 +190,39 @@ export class TransferOrchestrator {
       'published crypto.transfer.completed'
     );
   }
+
+  private async handleAlreadyClaimed(
+    message: CryptoTransferRequest,
+    existing: { status: string; web3_transaction_hash: string | null },
+    log: Logger
+  ): Promise<void> {
+    if (existing.status === 'usdt_delivered') {
+      log.info({ event: 'payment.already_delivered' }, 'already delivered, publishing completion');
+      await this.publishCompleted(message, log);
+      return;
+    }
+
+    if (existing.status === 'web3_processing') {
+      log.warn(
+        { event: 'payment.already_processing', tx_hash: existing.web3_transaction_hash },
+        'skip - payment is already claimed by another worker'
+      );
+      return;
+    }
+
+    if (existing.status === 'web3_hash_error' || existing.status === 'web3_balance_problem') {
+      log.warn(
+        { event: 'payment.terminal_state', status: existing.status },
+        'skip - payment already in terminal failure state'
+      );
+      return;
+    }
+
+    log.warn(
+      { event: 'payment.not_claimed', status: existing.status, tx_hash: existing.web3_transaction_hash },
+      'skip - payment was not claimed for transfer'
+    );
+  }
 }