> ## Documentation Index
> Fetch the complete documentation index at: https://docs.polygon.technology/llms.txt
> Use this file to discover all available pages before exploring further.

# Transaction lifecycle

> How a transaction moves through OMS from creation to completion, including statuses, sub-statuses, and webhook events.

Every transaction in OMS moves through a predictable set of statuses. The top-level `status` is designed for programmatic branching. The optional `subStatus` provides operational detail without complicating your core logic.

## Direction

Every transaction carries a `sourceToDestination` field: a composite of the source and destination instrument categories.

| Value                 | What it does                                                     |
| --------------------- | ---------------------------------------------------------------- |
| `cryptoToCrypto`      | USDC moves from one wallet to another, or to an external address |
| `cryptoToFiatAccount` | USDC out of a wallet, fiat delivered to a bank account           |
| `cryptoToCash`        | USDC out of a wallet, delivered as a cash pickup                 |
| `fiatAccountToCrypto` | Fiat in from a bank account, USDC delivered to a wallet          |
| `cashToCrypto`        | Cash in from a retail deposit, USDC delivered to a wallet        |

OMS infers the direction from the source and destination instruments. You do not set it explicitly.

## Status model

```
processing                      (initial state; the quote is already accepted)
    │
    ├──► completed              (standard flows)
    │
    ├──► awaitingAction         (non-terminal; blocked on developer, upstream, or compliance action)
    │        └──► processing    (once the hold clears)
    │
    └──► failed
```

The four top-level statuses are `processing`, `awaitingAction`, `completed`, and `failed`. A transaction begins at `processing` the moment it is created from a quote. `awaitingAction` is a non-terminal hold state; the `hold` object explains the reason and carries a deadline, and the transaction returns to `processing` once cleared.

The `hold` object is discriminated by its `type` field:

| `hold.type`              | Meaning                                                                                                                                                                                                                        |
| ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `senderAttribution`      | A deposit address received crypto from a sender not linked to a counterparty. Carries the inbound `txHash` and `matchableExternalAccountCriteria`; registering a matching `walletExternal` external account releases the hold. |
| `depositAddressFrozen`   | The deposit address is frozen.                                                                                                                                                                                                 |
| `depositAddressInactive` | The deposit address's destination external account became unusable. The `cause` object identifies the external account, its status, and the reason it became invalid.                                                          |

Each hold carries `since`, an optional `deadline`, and `resolvedAt` once cleared.

**Branch on `status` only.** The optional `subStatus` is a status-scoped string carrying operational detail namespaced by its parent status (for example `processing.fundsPulled`, `processing.cashPickupReady`, or `completed.cashPickupCollected`). Cash off-ramp lifecycle events surface here rather than as top-level statuses, and payout execution does too: `processing.awaitingCryptoOut`, `processing.cryptoOut`, `processing.awaitingFiatOut`, and `processing.fiatOut` track the crypto and fiat out-legs of a payout. Use `subStatus` for display and logging, not for control flow.

## Webhook events

OMS fires a webhook on every meaningful state change. Each delivery carries the full transaction object, so your handler reads the `status` (and, if needed, `subStatus`) directly off the payload. Polling `GET /transactions/{id}` is rarely necessary once webhooks are configured.

Subscribe to events through the Webhooks endpoints or the OMS Dashboard. A subscription is an endpoint URL plus the list of event types you want:

```
POST /webhooks
{
  "url": "https://your-app.example.com/oms/webhooks",
  "events": []
}
```

An empty `events` array (or `["*"]`) subscribes to every event type. The Webhooks endpoints support full CRUD (`GET`/`PATCH`/`DELETE /webhooks/{id}`), and the create response returns a signing secret once, which you use to verify the `Webhook-Signature` header on incoming deliveries.

Transaction events are namespaced by transfer type: `transaction.fiatToCrypto.*`, `transaction.cryptoToFiat.*`, and `transaction.cryptoToCrypto.*`, each with `processing`, `completed`, `failed`, and refund variants (plus `cashPickupReady` and `codeExpired` on the cash payout path). See the [webhook events catalog](/api-reference/webhook-events) for every event type and the delivery envelope.

## Auto-created transactions

Deposit addresses, virtual accounts, and cash-ins bypass the quote step. OMS creates the transaction internally when funds arrive and moves it directly to `processing`. The same status model and webhook events apply.

## Idempotency

All `POST` endpoints accept an `Idempotency-Key` header. Use a stable key (UUID tied to your internal order ID) to safely retry on network failure. OMS returns the same response for any subsequent request with the same key within the idempotency window.

<Tip>
  Set `Idempotency-Key` on every write request in production. It protects against double-execution without any coordination on your side.
</Tip>