ACH vs Wire Transfer — When to Use Which?

For non-US developers, the US domestic transfer system can be confusing. From an API perspective, there are fundamental differences between ACH (Automated Clearing House) and Wire transfers.

Technical & Operational Comparison

Feature

ACH Transfer

Wire Transfer

Settlement Time

1-3 business days (Same-Day ACH is available but depends on cut-offs).

Real-time (usually settles within minutes or hours on the same day).

Reversibility

Reversible within 60 days (e.g., for fraud or incorrect amounts).

Final and non-reversible (except for extremely rare bank technical errors).

Limits & Fees

Usually free. Ideal for mass payouts and payroll.

Carries a fee (around $15-$30). Ideal for large or urgent transactions.

Cut-off Time

Batch dependent (often around 1 PM EST).

Typically before 3 PM EST for same-day processing.

API Payload Comparison

When making a request to POST /api/v1/account/{account_id}/transactions, the main difference is the paymentMethod parameter.

ACH Payload Example:

{
  "recipientId": "rec_123456789",
  "amount": 500.00,
  "paymentMethod": "ach",
  "idempotencyKey": "ach-inv-001"
}

Wire Payload Example:

{
  "recipientId": "rec_987654321",
  "amount": 50000.00,
  "paymentMethod": "wire",
  "idempotencyKey": "wire-inv-001"
}

Tip

Do not use Wire for micro-transactions, as the fees will eat into your margins. Always use an idempotencyKey to prevent duplicate transactions during network timeouts.

See Also