# Start Transaction

You can use this call to start an existing Bancontact transaction using the CM.com Online Payments API.

## Prerequisite

Get an `access_token` and use it as 'Bearer' token in your request. Find more details [here](authorization-3).

## Request

```text
POST https://api.pay.cm.com/api/v1/paymentmethods/bancontact/v1/transactions/{transactionId}/start
```

```json Full Request
{
  "browserInformation": {
    "shopperIp": "0.0.0.0",
    "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
    "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.102 Safari/537.36 Edge/18.18363"
  },
  "encryptedCardDetails": {
    "data": "string"
  }
}
```

## Parameters

| Parameter            | Type                                                           | Description                  | Constraints |
| :------------------- | :------------------------------------------------------------- | :--------------------------- | :---------- |
| browserInformation   | [browserInformation](schemas-4#browserInformation)  Object     | Browser information details. |             |
| encryptedCardDetails | [encryptedCardDetails](schemas-4#encryptedCardDetails)  Object | Encrypted card details.      |             |

## Response

```json
{
  "id": "8db1e7fa-ba8a-4189-92fd-67a20217443d",
  "action": {
    "redirect": {
      "url": "https://issuer.tld/ideal/start?trxid=213981209381209390821&random=wreq0dq90vgq0ew923123"
    }
  }
}
```

## Parameters

| Parameter | Type                                                      | Description                                                                                                                                        | Constraints |
| :-------- | :-------------------------------------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------- | :---------- |
| id        | String(36)                                                | Unique identifier.                                                                                                                                 |             |
| action    | [action(redirect)](schemas-4#action\(redirect\))   Object | The next action to be performed by you for this transaction. This includes a URL where you should `redirect` your customer to perform the payment. |             |

## Response codes

| HTTP status | Description                                                                                                                                                                                                                                      |
| :---------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 201         | Transaction was started.                                                                                                                                                                                                                         |
| 4XX         | Client error response (See message for details). This response is given when the User input was incorrect or something illegal was attempted (eg. using a service without having that service configured for the user, or not being authorized). |
| 5XX         | Server error response (See message for details).                                                                                                                                                                                                 |