# Creating and Encoding Card-based Credentials

<figure><img src="https://2727122207-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FxnN2A67918om1UthYWsF%2Fuploads%2Fgit-blob-53db2a9e8f61049a6ca7659a0fb78d4d2fb4ed26%2Fencode-card.png?alt=media" alt=""><figcaption></figcaption></figure>

Some access control systems require encoding a plastic card with the data necessary to enable access. This process involves creating a credential with the required access permissions and then using a card encoder to write the credential onto the card.

This process consists of the following basic steps:

1. Set up an [access system user](https://docs.seam.co/latest/capability-guides/access-systems/user-management) and create a [credential](https://docs.seam.co/latest/capability-guides/managing-credentials#create-a-card-based-credential) with the `access_method` set to `card`.\
   See the [system integration guide](https://docs.seam.co/latest/device-and-system-integration-guides#access-control-systems) for your access system provider to learn specific requirements, such as configuring entrances and access schedules.\
   See [Set Up an Access System User and Card Credential](#id-1.-set-up-an-access-syseuser-and-card-credential).
2. Use the `/acs/encoders/list` endpoint to retrieve a list of available encoders. Then, choose the encoder that you want to use to write the credential onto the card.\
   See [Retrieve Encoders](#id-2.-retrieve-encoders).
3. Use the `/acs/encoders/encode_credential` endpoint to encode the credential onto the card, using the encoder that you have chosen.\
   See [Encode the Card](#id-3.-encode-the-card).
4. Confirm that the card was encoded successfully using polling or a [webhook](https://docs.seam.co/latest/developer-tools/webhooks).\
   See [Confirm Successful Encoding](#id-4.-confirm-successful-encoding). Also, see a list of [common encoding errors](#common-encoding-errors).

Once you have written a credential to a card, you cannot reuse the credential for another card. That is, you must create a separate credential for each card. However, you can reuse a card by re-encoding the card with a new credential.

***

## 1. **Set Up an Access System User and Card Credential**

This example shows how to create an access system user and card-based credential. Note that the `is_issued` property of the resulting credential is `false`, which means that the credential is ready to be written to a card and has not yet been used to encode a card.

{% hint style="info" %}
Depending on your specific access control system, creating an access system user or credential may require additional parameters. For details, see the [system integration guide](https://docs.seam.co/latest/device-and-system-integration-guides#access-control-systems) for your access system.
{% endhint %}

{% tabs %}
{% tab title="JavaScript" %}
**Code:**

```javascript
// Step 1:
// Create the new access system user.
const acsUser = await seam.acs.users.create({
  acs_system_id: "11111111-1111-1111-1111-111111111111",
  full_name: "Jane Doe",
  email_address: "jane@example.com"
});

// Step 2:
// Create a card-based credential for each entrance for the access system user.
const credential = await seam.acs.credentials.create({
  acs_user_id: acsUser.acs_user_id,
  access_method: "card",
  allowed_acs_entrance_ids: [
    // List the IDs of the entrances to which
    // you want to grant access.
    room101.seam_acs_entrance_id
  ],
  starts_at: "2024-12-01T15:00:00.000Z",
  ends_at: "2024-12-04T12:00:00.000Z"
});
```

**Output:**

```json
{
  acs_credential_id: '66666666-6666-6666-6666-666666666666',
  acs_user_id: '33333333-3333-3333-3333-333333333333',
  access_method: 'card',
  starts_at: '2024-12-01T15:00:00.000Z',
  ends_at: '2024-12-04T12:00:00.000Z',
  is_issued: false,
  ...
}
```

{% endtab %}

{% tab title="cURL" %}
**Code:**

```bash
# Step 1:
# Create the new access system user.
acs_user=$(curl -X 'POST' \
  'https://connect.getseam.com/acs/users/create' \
  -H 'accept: application/json' \
  -H "Authorization: Bearer ${SEAM_API_KEY}" \
  -H 'Content-Type: application/json' \
  -d "{
  \"acs_system_id\": \"11111111-1111-1111-1111-111111111111\",
  \"full_name\": \"Jane Doe\",
  \"email_address\": \"jane@example.com\"
}")

# Step 2:
# Create a card-based credential for each entrance for the access system user.
# In allowed_entrance_ids, list the IDs of the entrances to
# which you want to grant access.
credential=$(curl -X 'POST' \
  'https://connect.getseam.com/acs/credentials/create' \
  -H 'accept: application/json' \
  -H "Authorization: Bearer ${SEAM_API_KEY}" \
  -H 'Content-Type: application/json' \
  -d "{
  \"acs_user_id\": \"$(jq -r '.acs_user.acs_user_id' <<< ${acs_user})\",
  \"access_method\": \"card\",
  \"allowed_acs_entrance_ids\": [
    \"${entrance_id}\"
  ],
  \"starts_at\": \"2024-12-01T15:00:00.000Z\",
  \"ends_at\": \"2024-12-04T12:00:00.000Z\"
}")
```

**Output:**

```json
{
  "acs_credential":
    {
      "acs_credential_id": "66666666-6666-6666-6666-666666666666",
      "acs_user_id": "33333333-3333-3333-3333-333333333333",
      "access_method": "card",
      "starts_at": "2024-12-01T15:00:00.000Z",
      "ends_at": "2024-12-04T12:00:00.000Z",
      "is_issued": false,
      ...
    },
  "ok":true
}
```

{% endtab %}

{% tab title="Python" %}
**Code:**

```python
# Step 1:
# Create the new access system user.
acs_user = seam.acs.users.create(
  acs_system_id = "11111111-1111-1111-1111-111111111111",
  full_name = "Jane Doe",
  email_address = "jane@example.com"
)

# Step 2:
# Create a card-based credential for each entrance for the access system user.
credential = seam.acs.credentials.create(
  acs_user_id = acs_user.acs_user_id,
  access_method = "card",
  # List the IDs of the entrances to which
  # you want to grant access.
  allowed_acs_entrance_ids = [
    room_101.seam_acs_entrance_id
  ],
  starts_at = "2024-12-01T15:00:00.000Z",
  ends_at = "2024-12-04T12:00:00.000Z"
)
```

**Output:**

```
AcsCredential(
  acs_credential_id='66666666-6666-6666-6666-666666666666',
  acs_user_id='33333333-3333-3333-3333-333333333333',
  access_method='card',
  starts_at='2024-12-01T15:00:00.000Z',
  ends_at='2024-12-04T12:00:00.000Z',
  is_issued=False
  ...
)
```

{% endtab %}

{% tab title="Ruby" %}
**Code:**

```ruby
# Step 1:
# Create the new access system user.
acs_user = seam.acs.users.create(
  acs_system_id: "11111111-1111-1111-1111-111111111111",
  full_name: "Jane Doe",
  email_address: "jane@example.com"
)

# Step 2:
# Create a card-based credential for each entrance for the access system user.
credential = seam.acs.credentials.create(
  acs_user_id: acs_user.acs_user_id,
  access_method: "card",
  # List the IDs of the entrances to which
  # you want to grant access.
  allowed_acs_entrance_ids: [
    room_101.seam_acs_entrance_id
  ],
  starts_at: "2024-12-01T15:00:00.000Z",
  ends_at: "2024-12-04T12:00:00.000Z"
)
```

**Output:**

```
<Seam::Resources::AcsCredential:0x00410
  acs_credential_id="66666666-6666-6666-6666-666666666666"
  acs_user_id="33333333-3333-3333-3333-333333333333"
  access_method="card"
  starts_at="2024-12-01T15:00:00.000Z"
  ends_at="2024-12-04T12:00:00.000Z"
  is_issued=false
  ...
>
```

{% endtab %}

{% tab title="PHP" %}
**Code:**

```php
// Step 1:
// Create the new access system user.
$acs_user = $seam->acs->users->create(
  acs_system_id: "11111111-1111-1111-1111-111111111111",
  full_name: "Jane Doe",
  email_address: "jane@example.com"
);

// Step 2:
// Create a card-based credential for each entrance for the access system user.
$credential = $seam->acs->credentials->create(
  acs_user_id: $acs_user->acs_user_id,
  access_method: "card",
  allowed_acs_entrance_ids: [
    // List the IDs of the entrances to which
    // you want to grant access.
    $room_101->seam_acs_entrance_id
  ],
  starts_at: "2024-12-01T15:00:00.000Z",
  ends_at: "2024-12-04T12:00:00.000Z"
);
```

**Output:**

```json
{
  "acs_credential_id": "66666666-6666-6666-6666-666666666666",
  "acs_user_id": "33333333-3333-3333-3333-333333333333",
  "access_method": "card",
  "starts_at": "2024-12-01T15:00:00.000Z",
  "ends_at": "2024-12-04T12:00:00.000Z",
  "is_issued": false,
  ...
}
```

{% endtab %}

{% tab title="C#" %}
**Code:**

```csharp
// Step 1:
// Create the new access system user.
AcsUser acsUser = seam.UsersAcs.Create(
  acsSystemId: "11111111-1111-1111-1111-111111111111",
  fullName: "Jane Doe",
  emailAddress: "jane@example.com"
);

// Step 2:
// Create a card-based credential for each entrance for the access system user.
AcsCredential credential = seam.CredentialsAcs.Create(
  acsUserId: acsUser.acsUserId,
  accessMethod: "card",
  allowedAcsEntranceIds: new List<string>
  {
    // List the IDs of the entrances to which
    // you want to grant access.
    room_101.acsEntranceId
  },
  startsAt: "2024-12-01T15:00:00.000Z",
  endsAt: "2024-12-04T12:00:00.000Z"
);
```

**Output:**

```json
{
  "acs_credential_id": "66666666-6666-6666-6666-666666666666",
  "acs_user_id": "33333333-3333-3333-3333-333333333333",
  "access_method": "card",
  "starts_at": "2024-12-01T15:00:00Z",
  "ends_at": "2024-12-04T12:00:00Z",
  "is_issued": false,
  ...
}
```

{% endtab %}
{% endtabs %}

***

## 2. Retrieve Encoders

There may be multiple encoders at a location, so it’s important to select the right one to encode the credential.

This example shows how to retrieve all encoders in a building connected to a single access system. Once you've identified the encoder you'd like to use, save the `acs_encoder_id` of the chosen encoder for the next step.

{% tabs %}
{% tab title="JavaScript" %}
**Code:**

```javascript
await seam.acs.encoders.list({
  acs_system_ids: [buildingSystemId]
});
```

**Output:**

```json
[
  {
    acs_encoder_id: '33333333-4444-5555-6666-777777777777',
    display_name: 'Front Desk',
    ...
  },
  ...
]
```

{% endtab %}

{% tab title="cURL" %}
**Code:**

```bash
curl -X 'POST' \
  'https://connect.getseam.com/acs/encoders/list' \
  -H 'accept: application/json' \
  -H "Authorization: Bearer ${SEAM_API_KEY}" \
  -H 'Content-Type: application/json' \
  -d "{
  \"acs_system_ids\": [\"${building_system_id}\"]
}"
```

**Output:**

```json
{
  "acs_encoders": [
    {
      "acs_encoder_id": "33333333-4444-5555-6666-777777777777",
      "display_name": "Front Desk",
      ...
    },
    ...
  ],
  "ok": true
}
```

{% endtab %}

{% tab title="Python" %}
**Code:**

```python
seam.acs.encoders.list(
  acs_system_ids = [building_system_id]
)
```

**Output:**

```
[
  AcsEncoder(
    acs_encoder_id='33333333-4444-5555-6666-777777777777',
    display_name='Front Desk',
    ...
  )
  ...
]
```

{% endtab %}

{% tab title="Ruby" %}
**Code:**

```ruby
seam.acs.encoders.list(
  acs_system_ids: [building_system_id]
)
```

**Output:**

```
[
  <Seam::Resources::AcsEncoder:0x00410
    acs_encoder_id="33333333-4444-5555-6666-777777777777"
    display_name="Front Desk"
    ...
  >,
  ...
]
```

{% endtab %}

{% tab title="PHP" %}
**Code:**

```php
$seam->acs->encoders->list(
  acs_system_ids: [building_system_id]
);
```

**Output:**

```json
[
  {
    "acs_encoder_id": "33333333-4444-5555-6666-777777777777",
    "display_name": "Front Desk",
    ...
  },
  ...
]
```

{% endtab %}

{% tab title="C#" %}
**Code:**

```csharp
seam.EncodersAcs.List(
  acsSystemIds: new List<string>
  {
    buildingSystemId
  }
);
```

**Output:**

```json
{
  "acs_encoder_id": "33333333-4444-5555-6666-777777777777",
  "display_name": "Front Desk",
  ...
}
...
```

{% endtab %}
{% endtabs %}

***

## 3. Encode the Card

Use `/acs/encoders/encode_credential` to start the card writing procedure that stores the credential data on the plastic key card.

{% tabs %}
{% tab title="JavaScript" %}
**Code:**

```javascript
const encodingActionAttempt = await seam.acs.encoders.encodeCredential({
  acs_credential_id: credential.acs_credential_id,
  acs_encoder_id: encoder.acs_encoder_id
});
```

**Output:**

```json
{
  status: 'pending',
  action_attempt_id: '11111111-2222-3333-4444-555555555555",
  action_type: 'ENCODE_CREDENTIAL',
  result: null,
  error: null
}
```

{% endtab %}

{% tab title="cURL" %}
**Code:**

```bash
encoding_action_attempt=$(curl -X 'POST' \
  'https://connect.getseam.com/acs/encoders/encode_credential' \
  -H 'accept: application/json' \
  -H "Authorization: Bearer ${SEAM_API_KEY}" \
  -H 'Content-Type: application/json' \
  -d "{
  \"acs_credential_id\": \"$(jq -r '.acs_credential.acs_credential_id' <<< ${credential})\",
  \"acs_encoder_id\": \"${acs_encoder_id}\"
}")
```

**Output:**

```json
{
  "action_attempt":
    {
      "status": "pending",
      "action_attempt_id": "11111111-2222-3333-4444-555555555555",
      "action_type": "ENCODE_CREDENTIAL",
      "result": null,
      "error": null
    },
  "ok": true
}
```

{% endtab %}

{% tab title="Python" %}
**Code:**

```python
encoding_action_attempt = seam.acs.encoders.encode_credential(
  acs_credential_id = credential.acs_credential_id,
  acs_encoder_id = encoder.acs_encoder_id
)
```

**Output:**

```
ActionAttempt(
  status='pending',
  action_attempt_id='11111111-2222-3333-4444-555555555555',
  action_type='ENCODE_CREDENTIAL',
  result=null,
  error=null
)
```

{% endtab %}

{% tab title="Ruby" %}
**Code:**

```ruby
encoding_action_attempt = seam.acs.encoders.encode_credential(
  acs_credential_id: credential.acs_credential_id,
  acs_encoder_id: encoder.acs_encoder_id
)
```

**Output:**

```
<Seam::Resources::ActionAttempt:0x00410
  status="pending"
  action_attempt_id="11111111-2222-3333-4444-555555555555"
  action_type="ENCODE_CREDENTIAL"
  result=nil
  error=nil
>
```

{% endtab %}

{% tab title="PHP" %}
**Code:**

```php
$encoding_action_attempt = $seam->acs->encoders->encode_credential(
  acs_credential_id: $credential->acs_credential_id,
  acs_encoder_id: $encoder->acs_encoder_id
);
```

**Output:**

```json
{
  "status": "pending",
  "action_attempt_id": "11111111-2222-3333-4444-555555555555",
  "action_type": "ENCODE_CREDENTIAL",
  "result": null,
  "error": null
}
```

{% endtab %}

{% tab title="C#" %}
**Code:**

```csharp
actionAttempt encodingActionAttempt = seam.EncodersAcs.EncodeCredential(
  acsCredentialId: credential.acsCredentialId,
  acsEncoderId: encoder.acsEncoderId
);
```

**Output:**

```json
{
  "status": "pending",
  "action_attempt_id": "11111111-2222-3333-4444-555555555555",
  "action_type": "ENCODE_CREDENTIAL",
  "result": null,
  "error": null
}
```

{% endtab %}
{% endtabs %}

***

## 4. Confirm Successful Encoding

Once you issue a request to encode the credential onto the card, it is important to confirm that the encoding process completes successfully. You can use polling or a [webhook](https://docs.seam.co/latest/developer-tools/webhooks).

### Confirm Successful Encoding by Polling

When you make an `/acs/encoders/encode_credential` request, Seam returns an [action attempt](https://docs.seam.co/latest/core-concepts/action-attempts). To confirm that the card encoding was successful, you can poll this action attempt, until its `status` becomes `success`.

{% tabs %}
{% tab title="JavaScript" %}
**Code:**

```javascript
await seam.actionAttempts.get({
  action_attempt_id: encodingActionAttempt.action_attempt_id
});
```

**Output:**

```json
{
  status: 'success',
  action_attempt_id: '11111111-2222-3333-4444-555555555555",
  action_type: 'ENCODE_CREDENTIAL',
  result: {
    acs_credential_id: "66666666-6666-6666-6666-666666666666',
    card_number: '1234abc',
    is_issued: true,
    issued_at: '2024-10-23T19:46:06.113Z',
    ...
  },
  error: null
}
```

{% endtab %}

{% tab title="cURL" %}
**Code:**

```bash
curl -X 'POST' \
  'https://connect.getseam.com/action_attempts/get' \
  -H 'accept: application/json' \
  -H "Authorization: Bearer ${SEAM_API_KEY}" \
  -H 'Content-Type: application/json' \
  -d "{
  \"action_attempt_id\": \"$(jq -r '.action_attempt.action_attempt_id' <<< ${encoding_action_attempt})\"
}"
```

**Output:**

```json
{
  "action_attempt":
    {
      "status": "success",
      "action_attempt_id": "11111111-2222-3333-4444-555555555555",
      "action_type": "ENCODE_CREDENTIAL",
      "result": {
        "acs_credential_id": "66666666-6666-6666-6666-666666666666",
        "card_number": "1234abc",
        "is_issued": true,
        "issued_at": "2024-10-23T19:46:06.113Z",
        ...
      },
      "error": null
    },
  "ok": true
}
```

{% endtab %}

{% tab title="Python" %}
**Code:**

```python
seam.action_attempts.get(
  action_attempt_id = encoding_action_attempt.action_attempt_id
)
```

**Output:**

```
ActionAttempt(
  status='success',
  action_attempt_id='11111111-2222-3333-4444-555555555555',
  action_type='ENCODE_CREDENTIAL',
  result={
    acs_credential_id='66666666-6666-6666-6666-666666666666',
    card_number='1234abc',
    is_issued=True,
    issued_at='2024-10-23T19:46:06.113Z',
    ...
  },
  error=null
)
```

{% endtab %}

{% tab title="Ruby" %}
**Code:**

```ruby
seam.action_attempts.get(
  action_attempt_id: encoding_action_attempt.action_attempt_id
)
```

**Output:**

```
<Seam::Resources::ActionAttempt:0x00410
  status="success"
  action_attempt_id="11111111-2222-3333-4444-555555555555"
  action_type="ENCODE_CREDENTIAL"
  result={
    acs_credential_id="66666666-6666-6666-6666-666666666666"
    card_number="1234abc"
    is_issued=true,
    issued_at="2024-10-23T19:46:06.113Z"
    ...
  }
  error=nil
>
```

{% endtab %}

{% tab title="PHP" %}
**Code:**

```php
$seam->action_attempts->get(
  action_attempt_id: $encoding_action_attempt->action_attempt_id
);
```

**Output:**

```json
{
  "status": "success",
  "action_attempt_id": "11111111-2222-3333-4444-555555555555",
  "action_type": "ENCODE_CREDENTIAL",
  "result": {
    "acs_credential_id": "66666666-6666-6666-6666-666666666666",
    "card_number": "1234abc",
    "is_issued": true,
    "issued_at": "2024-10-23T19:46:06.113Z",
    ...
  },
  "error": null
}
```

{% endtab %}

{% tab title="C#" %}
**Code:**

```csharp
seam.ActionAttempts.Get(
  actionAttemptId: encodingActionAttempt.actionAttemptId
);
```

**Output:**

```json
{
  "status": "success",
  "action_attempt_id": "11111111-2222-3333-4444-555555555555",
  "action_type": "ENCODE_CREDENTIAL",
  "result": {
    "acs_credential_id": "66666666-6666-6666-6666-666666666666",
    "card_number": "1234abc",
    "is_issued": true,
    "issued_at": "2024-10-23T19:46:06.113Z",
    ...
  },
  "error": null
}
```

{% endtab %}
{% endtabs %}

#### View Credential Properties

It is also useful to note that Seam assigns values to various card-related properties on the credential when the encoder has finished encoding the card. For example, `acs_credential.is_issued` becomes `true`, and `acs_credential.card_number` and `acs_credential.issued_at` receive values. You can retrieve the credential to view these properties.

{% tabs %}
{% tab title="JavaScript" %}
**Code:**

```javascript
await seam.acs.credentials.get({
  acs_credential_id: credential.acs_credential_id
});
```

**Output:**

```json
{
  acs_credential_id: '66666666-6666-6666-6666-666666666666',
  acs_user_id: '33333333-3333-3333-3333-333333333333',
  access_method: 'card',
  starts_at: '2024-12-01T15:00:00.000Z',
  ends_at: '2024-12-04T12:00:00.000Z',
  is_issued: true,
  card_number: '1234abc',
  issued_at: '2024-10-23T19:46:06.113Z',
  ...
}
```

{% endtab %}

{% tab title="cURL" %}
**Code:**

```bash
curl -X 'POST' \
  'https://connect.getseam.com/acs/credentials/get' \
  -H 'accept: application/json' \
  -H "Authorization: Bearer ${SEAM_API_KEY}" \
  -H 'Content-Type: application/json' \
  -d "{
  \"acs_credential_id\": \"$(jq -r '.acs_credential.acs_credential_id' <<< ${credential})\"
}"
```

**Output:**

```json
{
  "acs_credential":
    {
      "acs_credential_id": "66666666-6666-6666-6666-666666666666",
      "acs_user_id": "33333333-3333-3333-3333-333333333333",
      "access_method": "card",
      "starts_at": "2024-12-01T15:00:00.000Z",
      "ends_at": "2024-12-04T12:00:00.000Z",
      "is_issued": true,
      "card_number": "1234abc",
      "issued_at": "2024-10-23T19:46:06.113Z",
      ...
    },
  "ok":true
}
```

{% endtab %}

{% tab title="Python" %}
**Code:**

```python
seam.acs.credentials.get(
  acs_credential_id = credential.acs_credential_id
)
```

**Output:**

```
AcsCredential(
  acs_credential_id='66666666-6666-6666-6666-666666666666',
  acs_user_id='33333333-3333-3333-3333-333333333333',
  access_method='card',
  starts_at='2024-12-01T15:00:00.000Z',
  ends_at='2024-12-04T12:00:00.000Z',
  is_issued=True,
  card_number='1234abc',
  issued_at='2024-10-23T19:46:06.113Z',
  ...
)
```

{% endtab %}

{% tab title="Ruby" %}
**Code:**

```ruby
seam.acs.credentials.get(
  acs_credential_id: credential.acs_credential_id
)
```

**Output:**

```
<Seam::Resources::AcsCredential:0x00410
  acs_credential_id="66666666-6666-6666-6666-666666666666"
  acs_user_id="33333333-3333-3333-3333-333333333333"
  access_method="card"
  starts_at="2024-12-01T15:00:00.000Z"
  ends_at="2024-12-04T12:00:00.000Z"
  is_issued=true
  card_number="1234abc"
  issued_at="2024-10-23T19:46:06.113Z"
  ...
>
```

{% endtab %}

{% tab title="PHP" %}
**Code:**

```php
$seam->acs->credentials->get(
  acs_credential_id: $credential->acs_credential_id
);
```

**Output:**

```json
{
  "acs_credential_id": "66666666-6666-6666-6666-666666666666",
  "acs_user_id": "33333333-3333-3333-3333-333333333333",
  "access_method": "card",
  "starts_at": "2024-12-01T15:00:00.000Z",
  "ends_at": "2024-12-04T12:00:00.000Z",
  "is_issued": true,
  "card_number": "1234abc",
  "issued_at": "2024-10-23T19:46:06.113Z",
  ...
}
```

{% endtab %}

{% tab title="C#" %}
**Code:**

```csharp
seam.CredentialsAcs.Get(
  acsCredentialId: credential.acsCredentialId
);
```

**Output:**

```json
{
  "acs_credential_id": "66666666-6666-6666-6666-666666666666",
  "acs_user_id": "33333333-3333-3333-3333-333333333333",
  "access_method": "card",
  "starts_at": "2024-12-01T15:00:00.000Z",
  "ends_at": "2024-12-04T12:00:00.000Z",
  "is_issued": true,
  "card_number": "1234abc",
  "issued_at": "2024-10-23T19:46:06.113Z",
  ...
}
```

{% endtab %}
{% endtabs %}

***

### Confirm Successful Encoding by Using a Webhook

To confirm successful encoding, you can use a [webhook](https://docs.seam.co/latest/developer-tools/webhooks) to listen for an `acs_credential.issued` event that contains the `acs_credential_id` in the payload. If you are re-encoding a card, listen for `acs_credential.reissued` instead of `acs_credential.issued`.

```json
{
  "event_id": "22222222-3333-4444-5555-666666666666",
  "event_description": "An ACS credential was issued.",
  "event_type": "acs_credential.issued",
  "workspace_id": "00000000-0000-0000-0000-000000000000",
  "created_at": "2024-10-23T19:47:35.375Z",
  "occurred_at": "2024-10-23T19:47:35.356Z",
  "acs_system_id": "11111111-1111-1111-1111-111111111111",
  "acs_credential_id": "66666666-6666-6666-6666-666666666666",
  "connected_account_id": "11111111-1111-1111-1111-222222222222"
}
```

***

## Common Encoding Errors

<table><thead><tr><th width="309">Error</th><th>Description</th></tr></thead><tbody><tr><td><code>no_card_on_encoder</code></td><td>No card was placed on the encoder.</td></tr><tr><td><code>incompatible_card_format</code></td><td>A card with an incompatible card format was placed on the encoder.</td></tr><tr><td><code>uncategorized_error</code></td><td>Any other encoding error.</td></tr></tbody></table>


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.seam.co/latest/capability-guides/access-systems/working-with-card-encoders-and-scanners/creating-and-encoding-card-based-credentials.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.