Swan — GraphQL Banking API

1
mutation InitiateSepaCreditTransfer($input: InitiateCreditTransferInput!) {
2
  initiateCreditTransfers(input: $input) {
3
    ... on InitiateCreditTransfersSuccessPayload {
4
      payment {
5
        id
6
        statusInfo { status }
7
      }
8
    }
9
    ... on ForbiddenRejection { message }
10
    ... on ValidationRejection { message fields { path message } }
11
  }
12
}

1
// Swan OAuth2 Token Exchange
2
const tokenResponse = await fetch('https://oauth.swan.io/oauth2/token', {
3
  method: 'POST',
4
  headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
5
  body: new URLSearchParams({
6
    grant_type: 'client_credentials',
7
    client_id: process.env.SWAN_CLIENT_ID!,
8
    client_secret: process.env.SWAN_CLIENT_SECRET!,
9
  }),
10
});
11
const { access_token } = await tokenResponse.json();

1
// Swan returns typed rejection unions instead of HTTP errors
2
type InitiateCreditTransfersPayload =
3
  | InitiateCreditTransfersSuccessPayload
4
  | ForbiddenRejection
5
  | ValidationRejection
6
  | InternalErrorRejection;
7
8
// YaniPay maps these to a BaaSError tagged union
9
import { Result } from '@swan-io/boxed';
10
type BaaSResult<T> = Result<T, BaaSError>;

1
import { Result } from '@swan-io/boxed';
2
import type { BaaSError } from '@/types/baas';
3
4
export async function initiateTransfer(
5
  input: TransferInput
6
): Promise<Result<Payment, BaaSError>> {
7
  const response = await swanClient.mutate(InitiateSepaCreditTransfer, { input });
8
9
  const payload = response.initiateCreditTransfers;
10
11
  if (payload.__typename === 'InitiateCreditTransfersSuccessPayload') {
12
    return Result.Ok(payload.payment);
13
  }
14
15
  // Typed rejection — no guessing
16
  return Result.Error({
17
    code: payload.__typename,
18
    message: payload.message,
19
    provider: 'swan',
20
  });
21
}

# Swan Sandbox Configuration
SWAN_ENVIRONMENT=sandbox
SWAN_API_URL=https://api.swan.io/sandbox-partner/graphql
SWAN_OAUTH_URL=https://oauth.swan.io/oauth2/token
SWAN_CLIENT_ID=your-sandbox-client-id
SWAN_CLIENT_SECRET=your-sandbox-client-secret
SWAN_PROJECT_ID=your-sandbox-project-id

1
import { describe, it, expect } from 'vitest';
2
import { swanClient } from '@/lib/baas/swan/client';
3
4
describe('Swan BaaS Integration', () => {
5
  it('should authenticate with sandbox credentials', async () => {
6
    const token = await swanClient.getAccessToken();
7
    expect(token).toBeDefined();
8
    expect(typeof token).toBe('string');
9
  });
10
11
  it('should fetch account details', async () => {
12
    const result = await swanClient.getAccount('sandbox-account-id');
13
    result.match({
14
      Ok: (account) => {
15
        expect(account.currency).toBe('EUR');
16
        expect(account.country).toBe('FRA');
17
      },
18
      Error: (error) => {
19
        throw new Error(`Unexpected error: ${error.message}`);
20
      },
21
    });
22
  });
23
24
  it('should initiate a SEPA credit transfer', async () => {
25
    const result = await swanClient.initiateTransfer({
26
      amount: { value: '10.00', currency: 'EUR' },
27
      targetIban: 'FR7630006000011234567890189',
28
      label: 'Test transfer',
29
    });
30
    expect(result.isOk()).toBe(true);
31
  });
32
});

1
query ListTransactions($accountId: ID!, $after: String) {
2
  account(accountId: $accountId) {
3
    transactions(first: 20, after: $after, filters: { status: Booked }) {
4
      edges {
5
        node {
6
          id
7
          amount { value currency }
8
          label
9
          bookedDate
10
          side
11
          statusInfo { status }
12
        }
13
        cursor
14
      }
15
      pageInfo {
16
        hasNextPage
17
        endCursor
18
      }
19
    }
20
  }
21
}