# Finish a bank login

`POST /customers/{id}/bank-link/exchange` · Skerry · Custody

Finish a bank login: send the `public_token` the bank login page returned, with the `link_token` it was started with. The link token must be one started for this customer, and is finished once (409 `bank_link_finished`, or `bank_link_expired` after its expiry). The answer is `{ data: [payee] }`, the payees the connection added, each announced as `payee.created`. Covered by mandates as `payee.create`; if it is held, send the same request again with `Skerry-Approval` once a person has approved it. Neither token is stored.

- Scope: payees:write
- Moves money: no
- Idempotency: optional
- Untrusted: data.name, data.name_check

## Parameters

- `id` (path, required), string
- `Idempotency-Key` (header), string: A repeat with the same key and body returns the first answer instead of acting twice.

## Request body

`application/json`

```json
{
  "type": "object"
}
```

## Responses

- `200`: Success.
- `202`: requires_approval — Not an error: the operation is held for a person. The body names the approval.
- `400`: price_below_minimum — The price is below the smallest single payment for a method (`detail.method`, `detail.minimum`), or has a part of a cent. Set `credit_only`, raise the price, or drop the method.
- `401`: dpop_invalid — The token is bound to a key and the DPoP proof was missing, wrong for this request, or already used.
- `402`: payment_failed — The payer's bank or card refused. `detail.reason` says why in plain terms.
- `403`: agent_payment_over_max — The merchant asks for more than `max_amount`. Nothing was signed. `detail.asked_minor` is the lowest price asked, in US cents.
- `404`: not_found — No such object in this project — including one that belongs to somebody else.
- `409`: token_not_issued — A delegated payment token could not be issued ready to use, for instance because the payer would have to act. Nothing was sent to the merchant.
- `429`: too_many_waiters — This key already has as many requests waiting (`?wait=`) as it may. Let one finish, or read without wait.
- `500`: internal_error — Ours. Quote the `request_id` and we can find the call.
- `502`: platform_error — A provider failed. Safe to retry with the same Idempotency-Key.
- `503`: oauth_unavailable — The authorisation server's keys could not be read, so tokens cannot be checked. API keys still work.

## Example

```sh
curl -X POST 'https://api.skerry.xyz/customers/{id}/bank-link/exchange' \
  -H 'Authorization: Bearer $KEY' \
  -H 'Content-Type: application/json' \
  -d '"{ link_token, public_token }"'
```