diff --git a/apps/web-wallet/app/features/receive/cashu-receive-swap-hooks.ts b/apps/web-wallet/app/features/receive/cashu-receive-swap-hooks.ts
index f5c56f52e..e207b2ac5 100644
--- a/apps/web-wallet/app/features/receive/cashu-receive-swap-hooks.ts
+++ b/apps/web-wallet/app/features/receive/cashu-receive-swap-hooks.ts
@@ -12,6 +12,7 @@ import {
   useSelectItemsWithOnlineAccount,
 } from '../accounts/account-hooks';
 import type { AgicashDbCashuReceiveSwap } from '../agicash-db/database';
+import { ConcurrencyError } from '../shared/error';
 import { useUser } from '../user/user-hooks';
 import type { CashuReceiveSwap } from './cashu-receive-swap';
 import { useCashuReceiveSwapRepository } from './cashu-receive-swap-repository';
@@ -163,8 +164,13 @@ export function useProcessCashuReceiveSwapTasks() {
       const account = getCashuAccount(swap.accountId);
       await receiveSwapService.completeSwap(account, swap);
     },
-    retry: 3,
-    throwOnError: true,
+    retry: (failureCount, error) => {
+      if (error instanceof ConcurrencyError) {
+        return true;
+      }
+      return failureCount < 3;
+    },
+    throwOnError: (error) => !(error instanceof ConcurrencyError),
     onError: (error, tokenHash) => {
       console.error('Error finalizing receive swap', {
         cause: error,
diff --git a/apps/web-wallet/app/features/receive/cashu-receive-swap-service.ts b/apps/web-wallet/app/features/receive/cashu-receive-swap-service.ts
index 5fdd7d302..7b0166d0b 100644
--- a/apps/web-wallet/app/features/receive/cashu-receive-swap-service.ts
+++ b/apps/web-wallet/app/features/receive/cashu-receive-swap-service.ts
@@ -9,11 +9,13 @@ import {
   CashuErrorCodes,
   areMintUrlsEqual,
   getCashuUnit,
+  isTransientCashuSwapError,
   sumProofs,
 } from '~/lib/cashu';
 import { Money } from '~/lib/money';
 import type { CashuAccount } from '../accounts/account';
 import { tokenToMoney } from '../shared/cashu';
+import { ConcurrencyError } from '../shared/error';
 import type { CashuReceiveSwap } from './cashu-receive-swap';
 import {
   type CashuReceiveSwapRepository,
@@ -244,6 +246,11 @@ export class CashuReceiveSwapService {
         // TODO: make sure these proofs are not already in our balance and that they are not spent
         return proofs;
       }
+
+      if (isTransientCashuSwapError(error)) {
+        throw new ConcurrencyError(error.message);
+      }
+
       throw error;
     }
   }
diff --git a/apps/web-wallet/app/features/send/cashu-send-swap-hooks.ts b/apps/web-wallet/app/features/send/cashu-send-swap-hooks.ts
index 7455677a2..43bed385e 100644
--- a/apps/web-wallet/app/features/send/cashu-send-swap-hooks.ts
+++ b/apps/web-wallet/app/features/send/cashu-send-swap-hooks.ts
@@ -411,8 +411,13 @@ export function useProcessCashuSendSwapTasks() {
         account,
       });
     },
-    retry: 3,
-    throwOnError: true,
+    retry: (failureCount, error) => {
+      if (error instanceof ConcurrencyError) {
+        return true;
+      }
+      return failureCount < 3;
+    },
+    throwOnError: (error) => !(error instanceof ConcurrencyError),
     onError: (error, swapId) => {
       console.error('Error swapping for proofs to send', {
         cause: error,
diff --git a/apps/web-wallet/app/features/send/cashu-send-swap-service.ts b/apps/web-wallet/app/features/send/cashu-send-swap-service.ts
index e611f55aa..d54a84cdb 100644
--- a/apps/web-wallet/app/features/send/cashu-send-swap-service.ts
+++ b/apps/web-wallet/app/features/send/cashu-send-swap-service.ts
@@ -12,6 +12,7 @@ import {
   type ExtendedCashuWallet,
   getCashuProtocolUnit,
   getCashuUnit,
+  isTransientCashuSwapError,
   sumProofs,
 } from '~/lib/cashu';
 import { Money } from '~/lib/money';
@@ -21,7 +22,7 @@ import {
 } from '../receive/cashu-receive-swap-service';
 import { getTokenHash } from '../shared/cashu';
 import { getDefaultUnit } from '../shared/currencies';
-import { DomainError } from '../shared/error';
+import { ConcurrencyError, DomainError } from '../shared/error';
 import type { CashuSendSwap } from './cashu-send-swap';
 import {
   type CashuSendSwapRepository,
@@ -457,6 +458,10 @@ export class CashuSendSwapService {
         };
       }
 
+      if (isTransientCashuSwapError(error)) {
+        throw new ConcurrencyError(error.message);
+      }
+
       throw error;
     }
   }
diff --git a/apps/web-wallet/app/lib/cashu/error-codes.test.ts b/apps/web-wallet/app/lib/cashu/error-codes.test.ts
new file mode 100644
index 000000000..c42f37295
--- /dev/null
+++ b/apps/web-wallet/app/lib/cashu/error-codes.test.ts
@@ -0,0 +1,51 @@
+import { describe, expect, test } from 'bun:test';
+import { MintOperationError } from '@cashu/cashu-ts';
+import { CashuErrorCodes, isTransientCashuSwapError } from './error-codes';
+
+const mintError = (code: CashuErrorCodes) =>
+  new MintOperationError(code, `mint error ${code}`);
+
+describe('isTransientCashuSwapError', () => {
+  test('treats OUTPUTS_ARE_PENDING (11004) as transient', () => {
+    expect(
+      isTransientCashuSwapError(mintError(CashuErrorCodes.OUTPUTS_ARE_PENDING)),
+    ).toBe(true);
+  });
+
+  test('treats PROOFS_ARE_PENDING (11002) as transient', () => {
+    expect(
+      isTransientCashuSwapError(mintError(CashuErrorCodes.PROOFS_ARE_PENDING)),
+    ).toBe(true);
+  });
+
+  test('does not treat OUTPUT_ALREADY_SIGNED (11003) as transient', () => {
+    expect(
+      isTransientCashuSwapError(
+        mintError(CashuErrorCodes.OUTPUT_ALREADY_SIGNED),
+      ),
+    ).toBe(false);
+  });
+
+  test('does not treat TOKEN_ALREADY_SPENT (11001) as transient', () => {
+    expect(
+      isTransientCashuSwapError(mintError(CashuErrorCodes.TOKEN_ALREADY_SPENT)),
+    ).toBe(false);
+  });
+
+  test('does not treat other mint operation errors as transient', () => {
+    expect(
+      isTransientCashuSwapError(
+        mintError(CashuErrorCodes.TRANSACTION_NOT_BALANCED),
+      ),
+    ).toBe(false);
+    expect(
+      isTransientCashuSwapError(mintError(CashuErrorCodes.KEYSET_INACTIVE)),
+    ).toBe(false);
+  });
+
+  test('does not treat non-mint errors as transient', () => {
+    expect(isTransientCashuSwapError(new Error('boom'))).toBe(false);
+    expect(isTransientCashuSwapError('outputs are pending')).toBe(false);
+    expect(isTransientCashuSwapError(undefined)).toBe(false);
+  });
+});
diff --git a/apps/web-wallet/app/lib/cashu/error-codes.ts b/apps/web-wallet/app/lib/cashu/error-codes.ts
index 65fb677c8..725d4b54c 100644
--- a/apps/web-wallet/app/lib/cashu/error-codes.ts
+++ b/apps/web-wallet/app/lib/cashu/error-codes.ts
@@ -1,3 +1,5 @@
+import { MintOperationError } from '@cashu/cashu-ts';
+
 /**
  * Based on https://github.com/cashubtc/nuts/blob/main/error_codes.md
  */
@@ -216,3 +218,18 @@ export enum CashuErrorCodes {
    */
   BAT_MINT_RATE_LIMIT_EXCEEDED = 31004,
 }
+
+/**
+ * Whether the error is a transient swap error returned by the mint: the outputs or
+ * input proofs are still in flight in a parallel operation (codes 11002 and 11004).
+ * The mint settles them on its own, so the swap should be retried rather than failed.
+ * @see https://github.com/cashubtc/nuts/blob/main/error_codes.md
+ */
+export const isTransientCashuSwapError = (
+  error: unknown,
+): error is MintOperationError =>
+  error instanceof MintOperationError &&
+  [
+    CashuErrorCodes.PROOFS_ARE_PENDING,
+    CashuErrorCodes.OUTPUTS_ARE_PENDING,
+  ].includes(error.code);