<!-- Source: https://blnkfinance.com/glossary/payment-rail -->

[Glossary](https://blnkfinance.com/glossary) Payment rail

# What is a payment rail?

Payment rail

A payment rail is the network that moves money between banks or wallets. ACH, RTP, FedNow, and wire are rails. A ledger is not a rail. The rail settles the bank money. The ledger records who owes whom while that happens.

## How does a payment rail work?

A sender’s bank puts an instruction on the network. The network clears it with the receiver’s bank. Hours or days later, the banks settle. Your product sits in the middle: it takes the customer’s request, talks to a bank or PSP, and waits for the rail to finish.

## Payment rail vs ledger

The rail moves central-bank or commercial-bank money. The ledger is your book of record. If you treat the rail as the source of truth, every retry and every partial file becomes a dispute. If you treat the ledger as the book, the rail is an event you record and reconcile.

## Which rail should you use?

Pick the rail for speed, cost, and whether the payment can be reversed. ACH is cheap and slow. Same-day ACH is still ACH. RTP and FedNow are instant and usually final. Wires are high-value and expensive. Cards are a different network with their own chargebacks.

| Rail | Speed | Typical use |
| --- | --- | --- |
| ACH | Hours to days | Payroll, bill pay, bank transfers |
| RTP | Seconds | Account-to-account, request for pay |
| FedNow | Seconds | Instant US bank payments |
| Wire | Minutes to hours | Large, one-off transfers |

## How it works with Blnk

Blnk records the movement. Your bank or PSP still sends it on ACH, RTP, FedNow, or wire.

You post from a named source to a named destination when the customer sends or receives. For a deposit, the source is `@WorldUSD_ACH` and the destination is the customer wallet. Keep the amount inflight until the rail settles, then commit. If the rail fails or returns, void it.

We use `@WorldUSD_ACH` because it is a system balance that belongs to the organization. Blnk calls these [internal balances](https://docs.blnkfinance.com/balances/internal-balances).

Record a deposit in four steps:

1.  1
    
    Name the source and destination
    
    The source is the balance that loses the amount. The destination is the balance that gains it. For this deposit, debit `@WorldUSD_ACH` and credit the customer wallet.
    
2.  2
    
    Record the transfer inflight
    
    Create the transaction with `inflight: true`. Settled balances stay unchanged until you commit or void.
    
    <!-- record-deposit.ts -->
    ```
    await blnk.Transactions.create({
      precise_amount: 25000,
      precision: 100,
      reference: 'pay_in_20260816_001',
      currency: 'USD',
      source: '@WorldUSD_ACH',
      destination: 'customer_wallet_id',
      description: 'Deposit via ACH',
      inflight: true,
      meta_data: {
        rail: 'ach',
        processor: 'modern_treasury',
        external_id: 'pt_9c2e1a74',
        customer_id: 'cus_8f21a4',
      },
    });
    ```
    
3.  3
    
    Commit the settlement or void a failure
    
    Commit when the rail settles. Void the post if the rail fails or returns. See [update inflight](https://docs.blnkfinance.com/transactions/inflight/updating-inflight).
    
    <!-- Commit -->
    ```
    await blnk.Transactions.updateStatus(
      'txn_c4e70eb8-e4d6-4e04-a2e2-92a43b969e0c',
      { status: 'commit' },
    );
    ```
    
    <!-- Void -->
    ```
    await blnk.Transactions.updateStatus(
      'txn_c4e70eb8-e4d6-4e04-a2e2-92a43b969e0c',
      { status: 'void' },
    );
    ```
    
4.  4
    
    Match the bank or PSP file
    
    Upload the bank or PSP file in [reconciliation](https://docs.blnkfinance.com/reconciliations/overview) and match each line so one ledger covers every rail.
    

Related terms

-   [ACH](https://blnkfinance.com/glossary/ach)
-   [RTP](https://blnkfinance.com/glossary/rtp)
-   [FedNow](https://blnkfinance.com/glossary/fednow)
-   [Wire](https://blnkfinance.com/glossary/wire)
-   [Settlement](https://blnkfinance.com/glossary/settlement)