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

> ## Agent Instructions
> HEVN accounts are non-custodial in both products. Self-serve (the General tab): the person who owns the email holds the only key and signs for themselves. Whitelabel (the Whitelabel and REST API tabs): the integrator's customer creates and owns their account through Sign in with HEVN, a HEVN-hosted popup on the integrator's site; the integrator's backend holds a developer key, operates linked accounts and books their payouts, and the account holder approves every payout in that popup. The developer key signs only for the integrator's own wallet; it never signs a client's money.
> Use HEVN's terms exactly. A rail is a bank route a client can request. A virtual account (bnk_) is an opened rail. Account details are what a payer needs in order to wire money, and arrive in a field named requisites. A client is a customer's own account linked to the integrator through Sign in with HEVN (POST /dapi/v1/connect/sessions, then POST /dapi/v1/clients/link); there is no API call that creates one. The business behind it is the integrator's customer. A contact is a saved destination; a beneficiary is the party at the far end of a fiat payout. Every departure of money is a payout, to a bank account or to a wallet alike.
> Never name a banking partner. Say 'a licensed banking partner'.
> There are no published fee rates, spreads or minimums. Prices come from a quote on a specific payment; direct pricing questions to HEVN rather than inventing numbers.
> The whitelabel API is at /dapi/v1 and takes a developer-key session plus an X-Hevn-Account header. Developer keys have an IP allowlist and no scopes. Remote transfers are at /api/v1/remote_spend_limit and take a remote transfer key (rsl_) in X-Api-Key, bounded by an onchain spend permission the account holder grants. They are different credentials and neither works on the other surface. The HEVN CLI is discontinued.

# Payins

> Quote incoming fiat, hand the payer instructions, and watch it settle onto the client's wallet.

Money arrives four ways: a quoted deposit you priced, a quoted on-chain transfer you priced, an unsolicited wire to account details that are already live, or crypto sent straight to the wallet. All four end as one income row on the client's ledger.

| Shape | What you call | What the payer needs |
| - | - | - |
| **Quoted deposit** | `POST /dapi/v1/payins` with `rail`, then `POST /dapi/v1/payins/{payinId}/instructions` | The instructions that quote returns, payment reference included |
| **Quoted on-chain transfer** | `POST /dapi/v1/payins` with `originChainId`, then the same instructions call | The `address`, `chainId` and `memo` the instructions return |
| **Unsolicited wire** | Nothing — the account details stay live | The `requisites` on the client's active rail from `GET /dapi/v1/banks` |
| **Crypto** | Nothing | The client's `baseSmartWallet` address |

Quote a payin when you need the rate and the fee pinned before the payer pays, and when you want their transfer attributed to one order. Take an unquoted path when the client publishes its own details and reconciles afterwards.

```mermaid theme={null}
flowchart LR
    Q["POST /dapi/v1/payins<br/>price the deposit"] --> I["POST /dapi/v1/payins/pi_2b7/instructions<br/>what the payer needs"]
    I --> W["Payer wires"]
    W --> C["Partner converts"]
    C --> B["Client's wallet credited<br/>+ income row"]
    W -.->|"sandbox"| S["POST /dapi/v1/sandbox/payins/pi_2b7/complete"]
    S --> C
```

Send `X-Hevn-Account: cl_…` with your own access token to act for one client. On a resource route
like `GET /banks` the header is optional: omit it and the call acts on your integrator account
instead. The singular `/client*` routes **require** it — the header is the only thing that names the
account — and `/clients*`, `/connect/sessions` and `/escrow*` refuse it.

```bash cURL theme={null}
curl "$HEVN_API/banks" \
  -H "Authorization: Bearer $HEVN_ACCESS_TOKEN" \
  -H "X-Hevn-Account: $HEVN_CLIENT_ID"
```

```python Python theme={null}
northwind = hevn.acting_as(CLIENT_ID)
rails = northwind.get("/banks")
```

```javascript Node theme={null}
const northwind = hevn.actingAs(clientId);
const rails = await northwind.get("/banks");
```

```go Go theme={null}
northwind := api.ActingAs(clientID)
rails, err := northwind.Get("/banks")
```

The whole table — where the header is optional, where it is required and where it is refused — is
in [Sessions](https://docs.gethevn.com/whitelabel/sessions.md#acting-as-a-client).

## Quote a deposit

The client needs an **active rail** in the currency the payer sends — see [Virtual accounts](https://docs.gethevn.com/whitelabel/virtual-accounts.md).

**1. Price the deposit**

```bash cURL theme={null}
curl -s -X POST "$HEVN_API/payins" \
  -H "Authorization: Bearer $HEVN_ACCESS_TOKEN" \
  -H "X-Hevn-Account: $HEVN_CLIENT_ID" \
  -H "Content-Type: application/json" \
  -d '{"amount":"2000.00","currency":"EUR","rail":"sepa","destinationAccount":"EURC"}'
```

```python Python theme={null}
payin = northwind.post("/payins", {
    "amount": "2000.00",
    "currency": "EUR",
    "rail": "sepa",
    "destinationAccount": "EURC",
})
```

```javascript Node theme={null}
const payin = await northwind.post("/payins", {
  amount: "2000.00",
  currency: "EUR",
  rail: "sepa",
  destinationAccount: "EURC",
});
```

```go Go theme={null}
payin, err := northwind.Post("/payins", hevn.Body{
	"amount":          "2000.00",
	"currency":        "EUR",
	"rail":            "sepa",
	"destinationAccount": "EURC",
})
```

```json Response — 201, Location: /dapi/v1/payins/pi_2b7… theme={null}
{ "id": "pi_2b7…", "status": "pending", "rail": "sepa",
  "quote": { "amount": "2000.00", "currency": "EUR",
             "settlementAmount": "1989.50", "destinationAccount": "EURC",
             "feeAmount": "10.50", "feeCurrency": "EUR", "rate": "1.0000" },
  "expiresAt": "2026-09-17T10:06:11Z", "createdAt": "2026-09-17T10:04:11Z" }
```

Four decisions:

* **`amount` or `amountTo`, exactly one.** `amount` is what the payer sends in `currency`; `amountTo` is what should land on the wallet, and HEVN grosses the payer's side up to reach it.
* **`rail` or `originChainId`, exactly one.** `rail` prices money arriving over a payment method; `originChainId` prices money arriving on a chain. Sending both, or neither, is refused.
* **`rail` here is a payment *method*** — `sepa`, `ach`, `swift`, `fedwire`, `pix`, … — not the product you requested with `POST /dapi/v1/banks`. The two are different vocabularies; [Rails](https://docs.gethevn.com/whitelabel/reference/rails.md) lists both.
* **`destinationAccount`** is the account the payin is delivered into, `USDC` (the default) or `EURC`. It has to be an account one of the client's matching rails settles into; when it is not, the call refuses with the pairs that work (see below). Money arriving over a rail always lands on the wallet, so `FDIC_USD` and `FDIC_EUR` are refused here with `422 account_not_supported`.

The price holds until `expiresAt`. Read it; do not cache a quote.

**2. Open it and read the instructions**

```bash cURL theme={null}
curl -s -X POST "$HEVN_API/payins/pi_2b7…/instructions" \
  -H "Authorization: Bearer $HEVN_ACCESS_TOKEN" \
  -H "X-Hevn-Account: $HEVN_CLIENT_ID" \
  -H "Content-Type: application/json" -d '{}'
```

```python Python theme={null}
instructions = northwind.post(f"/payins/{payin['id']}/instructions", {})
```

```javascript Node theme={null}
const instructions = await northwind.post(`/payins/${payin.id}/instructions`, {});
```

```go Go theme={null}
instructions, err := northwind.Post("/payins/"+payin.Str("id")+"/instructions", hevn.Body{})
```

```json Response — 200 theme={null}
{ "payinId": "pi_2b7…", "kind": "bank_transfer",
  "amount": "2000.00", "currency": "EUR",
  "paymentReference": "HEVN-7QF3K2", "singleUse": true,
  "requisites": { "fields": { "iban": "MT84…", "bic": "BANKMTMT" },
                  "holder": { "type": "business", "businessName": "Northwind Trading Ltd" },
                  "bankName": "Bank A", "state": "active" } }
```

Hand `requisites` to the payer verbatim, **`paymentReference` included** — on a pooled account it is the only thing that attributes the money to this payin.

`kind` says where the payer acts: `bank_transfer` (use `requisites`), `qr_code` (`qrPayload`), `hosted_page` (`url`), `manual`, or `onchain` (`address`, `chainId` and `memo`).

`singleUse` says whether the account details may receive another payment. Build as if it were always `true`: the instructions belong to this payin, and they are used up once money is sent to them. Never save them, and never show them for a second payment. A partner can answer `false` for a standing account, but the amount, the reference and `expiresAt` still belong to this one payin. The account details meant for repeat payments are the ones on an active rail — see [Unsolicited wires](#unsolicited-wires-to-the-clients-account-details).

Opening the same payin again returns the same instructions — that is the safe retry, not a way to create a second payin. Once the price stops holding it answers `410 payin_expired`; quote again.

**3. Watch it settle**

`GET /dapi/v1/payins/{payinId}` carries the payin through its whole life. Settlement is driven by the partner's own reports, so poll it rather than waiting on a response.

```python Python theme={null}
import random, time


def poll_until(read, done, *, deadline=120.0, first=1.0, cap=8.0):
    """Call read() until done(value) is true. Returns the last value or raises TimeoutError."""
    started, delay = time.monotonic(), first
    while True:
        value = read()
        if done(value):
            return value
        if time.monotonic() - started > deadline:
            raise TimeoutError(f"still {value.get('status')} after {deadline:.0f}s")
        time.sleep(delay + random.uniform(0, delay / 2))
        delay = min(delay * 2, cap)
```

```javascript Node theme={null}
export async function pollUntil(read, done, { deadline = 120_000, first = 1_000, cap = 8_000 } = {}) {
  const until = Date.now() + deadline;
  let delay = first;
  for (;;) {
    const value = await read();
    if (done(value)) return value;
    if (Date.now() > until) throw new Error(`still ${value.status} after ${deadline}ms`);
    await new Promise((wake) => setTimeout(wake, delay + Math.random() * (delay / 2)));
    delay = Math.min(delay * 2, cap);
  }
}
```

```go Go theme={null}
func PollUntil[T any](read func() (T, error), done func(T) bool, deadline time.Duration) (T, error) {
	until, delay := time.Now().Add(deadline), time.Second
	for {
		value, err := read()
		if err != nil {
			return value, err
		}
		if done(value) {
			return value, nil
		}
		if time.Now().After(until) {
			return value, fmt.Errorf("hevn: still pending after %s", deadline)
		}
		time.Sleep(delay + time.Duration(rand.Int63n(int64(delay/2))))
		if delay < 8*time.Second {
			delay *= 2
		}
	}
}
```

| `status` | Meaning |
| - | - |
| `pending` | Priced. Nothing has arrived. |
| `awaitingFunds` | Open, instructions issued, waiting for the payer. |
| `processing` | The partner has the money and is converting it. |
| `inReview` | Held pending an information request about the payment. |
| `completed` | Settled. The tokens are on the client's wallet. |
| `failed`, `canceled` | It will not arrive. Quote again. |
| `refunded` | Returned to the payer. |

## How long a payin lives

A payin has two windows, and `expiresAt` reports whichever one applies.

| Stage | Window | When it closes |
| - | - | - |
| Quoted, not opened | About two minutes | Opening answers `410 payin_expired`. Quote again. |
| Opened, waiting for the payer | Usually a few hours | Money that arrives later can be returned to the payer. |

If nobody pays, nothing happens: the payin expires and nothing is charged. An unpaid payin never appears in `GET /dapi/v1/transactions`, and there is no route that lists payins. Store `payinId` when you quote; a payin whose id you lost is one you can no longer reach.

Once money arrives, a `pending` income row appears on the ledger. It ends as `success`, `refunded`, or `rfi` when the partner asks about the payment ([Balances and transactions](https://docs.gethevn.com/whitelabel/balances-and-transactions.md)).

## When the payer gets it wrong

Quoted instructions are matched on what the payer sends, so a mistake costs time. Money is not lost as long as the currency is right and the reference (or `memo`) is there.

| Mistake | What happens |
| - | - |
| Bank transfer, right currency and reference, different amount | Usually the amount actually sent is credited. Some partners return it to the payer instead. |
| Bank transfer, wrong currency or missing reference | The money may not be attributable. Recovering it goes through HEVN support and can take a long time. |
| On-chain, different amount | Returned to the sender, usually within a few hours. |
| On-chain, wrong chain or wrong token | Stuck. Recovering it is possible, but slow and handled case by case with HEVN. |

That is why quoted bank payins suit payers who copy the instructions exactly. When a person types account details by hand, the standing account details of an active rail are the safer path.

## Quote an on-chain transfer

`originChainId` in place of `rail` prices money arriving on a chain instead of through a bank. The body is otherwise the same call:

```json theme={null}
{ "amount": "2000.00", "currency": "USDC", "originChainId": "arb", "destinationAccount": "USDC" }
```

`PayinView` then carries `originChainId` — the network the payer funds from — and `destinationChainId`, the network the payin settles on. Open it with the same `POST /dapi/v1/payins/{payinId}/instructions`, and the instructions answer `kind: "onchain"` with the three fields a sender needs:

```json Response — 200 theme={null}
{ "payinId": "pi_5d3…", "kind": "onchain",
  "amount": "2000.00", "currency": "USDC", "singleUse": true,
  "address": "0x9b41…", "chainId": "arb", "memo": null }
```

`memo` is the destination tag some networks route on. When it is present it is as load-bearing as a `paymentReference` — a transfer that omits it cannot be attributed. `ChainCode` is the same vocabulary a wallet contact uses; `base`, `arb`, `sol` and the rest are listed on the [rail reference](https://docs.gethevn.com/whitelabel/reference/rails.md).

This is the quoted arm of crypto-in. The unquoted arm — send straight to the wallet, no call at all — is further down.

## What a virtual account converts at

`GET /dapi/v1/banks/{product}/rate` answers `{currency, rate, fixedFee, fixedFeeCurrency}` — the indicative price of a deposit over that product's rail. On a product the client has not requested, only `currency` comes back. Use it to show a rate in your own UI before the payer commits to an amount. It is indicative: `POST /dapi/v1/payins` returns the number you are held to.

## When the payer has to be named

Some rails require the payer's own account so the receiving bank can check the sender. `POST /dapi/v1/payins/{payinId}/instructions` takes it:

```json theme={null}
{ "payer": { "method": "sepa",
             "requisites": { "method": "sepa", "currency": "EUR",
                             "fields": { "iban": "DE89370400440532013000", "bic": "COBADEFFXXX" },
                             "holder": { "type": "business", "businessName": "Payer GmbH" } } } }
```

`payer.requisites.method` has to equal `payer.method`. When a rail needs the payer and you omit it, the call answers `400 invalid_request` and names the fields it wants in `message` — that refusal carries no `details`. `details.options[].payerRequired` on a refused quote is the part you can branch on, and it tells you in advance which pairs demand a payer.

## When a pair cannot be paid

A currency and method the client cannot be paid in answers `422 payin_not_available`, and `details.options` carries every pair that **can** — each with `rail`, `currency`, `available`, `minAmount`, `maxAmount`, `feeBps`, `fixedFee`, `payerRequired` and `destinationAccounts`. Read the options rather than pre-flighting: the refusal is the capability catalogue.

`410 payin_expired` and `404 payin_not_found` are the other two you will meet; both carry `details.payinId`. [Errors](https://docs.gethevn.com/whitelabel/reference/errors.md#rails-and-payins) has the rest.

## Unsolicited wires to the client's account details

An active rail's account details stay live between payments. Anyone can wire to them with no quote and no API call from you.

1. Read `requisites` for the active rail from `GET /dapi/v1/banks`.
2. Give the payer the fields it carries, plus `paymentReference` when one is set.
3. The deposit lands as an income row on `GET /dapi/v1/transactions`, carrying `remitter` where the partner reports the sender, `paymentReference`, and the receiving account details.

> [!NOTE]
>
> Some partners report no sender at all. When `remitter` is absent on a settled deposit, the sender cannot be recovered from the API — treat it as unknown rather than retrying.

## Crypto straight to the wallet

The client's smart wallet is an ordinary address on Base. Read it from `GET /dapi/v1/client/balance` — with the client id in `X-Hevn-Account` — as `baseSmartWallet` and publish it; anything sent there is the client's. Nothing is quoted on this path, and there is no payin record: use the quoted on-chain arm above when you need a price or an attributed transfer.

> [!WARNING]
>
> Only **USDC and EURC on Base** are tracked. Other tokens, and the same tokens on other chains, sit at the address without ever becoming a balance or a transaction.

## In the sandbox

The partner is emulated, so a quoted payin waits forever until you complete it yourself. One call does what the payer would have done:

```bash cURL theme={null}
curl -s -X POST "$HEVN_API/sandbox/payins/pi_2b7f14c0a9/complete" \
  -H "Authorization: Bearer $HEVN_ACCESS_TOKEN" \
  -H "X-Hevn-Account: $HEVN_CLIENT_ID" \
  -H "Content-Type: application/json" \
  -d '{"remitter":"Payer GmbH"}'
```

```python Python theme={null}
settled = northwind.post(f"/sandbox/payins/{payin['id']}/complete", {"remitter": "Payer GmbH"})
```

```javascript Node theme={null}
const settled = await northwind.post(`/sandbox/payins/${payin.id}/complete`,
  { remitter: "Payer GmbH" });
```

```go Go theme={null}
settled, err := northwind.Post("/sandbox/payins/"+payin.Str("id")+"/complete",
	hevn.Body{"remitter": "Payer GmbH"})
```

`POST /dapi/v1/sandbox/deposits` covers the other two unquoted shapes: with `bankId` it emulates an unsolicited wire to that rail, without one it credits the smart wallet with tokens. Both are in [Sandbox](https://docs.gethevn.com/whitelabel/sandbox.md#mint-money).

> [!NOTE]
>
> The sandbox is the same API against one emulated partner on Base Sepolia. It runs on shared testnet money, so it is capped: **at most 1 per payout, escrow or payin**, a faucet that sends **at most 5, only to a wallet holding less than 1**, and **60 money calls per account per hour**. Full table in [Limits](https://docs.gethevn.com/whitelabel/reference/limits.md#sandbox).

> [card] [Next: Payouts](https://docs.gethevn.com/whitelabel/payouts.md)
>
> Money out: price and book a bank payout in one call, sign it in the next.


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