Synapto Flow Overview

BETA: Synapto Flow is subject to change without notice.

Synapto Flow lets platforms manage accounts, track balances, and move money between them. Use Flow to build multi-party payment experiences — onboard sub-accounts, distribute funds from charges, and pay out to bank accounts.

Flow builds on top of Synapto's payment collection capabilities. Charges collected through payment intents, checkout sessions, or invoices generate balance, which Flow lets you track, split, and pay out.

Core concepts

Accounts

A platform creates embedded accounts under its own account. Embedded accounts hold balance and receive funds via transfers — they don't process card payments directly.

See Accounts for the full guide.

Balances

Every account with the balance capability has a balance broken down into positions:

• Available — funds that can be transferred or paid out
• Pending — expected funds not yet available (e.g. charges awaiting settlement)
• Reserved — funds locked for a pending outflow (e.g. a payout in progress)

Individual transactions are recorded as balance lines, each with a state (PENDING, RESERVED, or SETTLED) and a type (CHARGE, TRANSFER, PAYOUT, or REFUND).

Settlement

Funds from a charge are not immediately available. Here is the full lifecycle from payment to settlement:

1. Payment intent created — state is REQUIRES_PAYMENT_METHOD. No balance impact yet.
2. Payment confirmed and charge succeeds — payment intent state moves to SUCCEEDED, charge state is SUCCEEDED. A PENDING balance line (type CHARGE) is created. Funds appear in the pending balance position.
3. Funds settle — the balance line moves from PENDING to SETTLED. Funds move from the pending position to available and can now be transferred or paid out.

The payment intent and charge states do not change at settlement — they remain SUCCEEDED from step 2 onwards. Settlement is tracked entirely through balance line states. See Custodial Balances for details.

See Balances for the full guide.

External bank accounts

Before paying out, an account must register an external bank account — the destination for payouts. Supported schemes are UK domestic (sort code + account number), IBAN, and US domestic (routing number + account number).

See External Bank Accounts for the full guide.

Payouts

A payout moves funds from an account's available balance to a registered external bank account. Payouts require approval in the Dashboard before they are submitted.

See Payouts for the full guide.

Transfers

A transfer moves funds between a parent account and one of its child accounts. Transfers settle immediately and are recorded as balance lines on both accounts.

See Transfers for the full guide.

Typical integration flow

1. Create an embedded account for each entity that needs to hold balance (e.g. a seller on your marketplace)
2. Collect payments using payment intents or checkout sessions on the parent account, with transfers configured to split funds to child accounts
3. Track balances as charges settle and transfers complete
4. Register external bank accounts for each account that needs to pay out
5. Create payouts to move available balance to bank accounts

Webhook events

Flow publishes events for transfers, payouts, charges, invoices, and settlement. See Flow Webhook Events for the full list.

Next steps

• Accounts — creating and managing embedded and standalone accounts
• Balances — tracking balance positions and lines for embedded accounts
• Custodial Balances — custodial balance and suspense for standalone accounts
• External Bank Accounts — registering payout destinations
• Payouts — paying out to bank accounts
• Transfers — moving funds between accounts
• Charge Splits — splitting payment proceeds to child accounts
• Flow Webhook Events — event types for Flow resources
• API Reference — full endpoint documentation