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

# Understanding Code Constraints

> Learn about manufacturer- and device-specific constraints on codes.

When creating access codes, it is important to be aware of any constraints on the `code`. [Get a device](/api/devices/get) and review its `device.properties.code_constraints`. Seam represents each constraint as an object with a `constraint_type` property. Depending on the constraint type, there may also be additional properties. Note that some constraints are manufacturer- or device-specific.

The `constraint_type` property can be any of the following enum values:

<table>
  <thead>
    <tr>
      <th width="338">Constraint Type</th>
      <th>Description</th>
    </tr>
  </thead>

  <tbody>
    <tr>
      <td>
        <code>no\_zeros</code>
      </td>

      <td>
        Cannot use <code>0</code>s as digits in the PIN code.
      </td>
    </tr>

    <tr>
      <td>
        <code>cannot\_start\_with\_12</code>
      </td>

      <td>
        PIN code cannot start with the sequence of digits <code>12</code>.
      </td>
    </tr>

    <tr>
      <td>
        <code>no\_triple\_consecutive\_ints</code>
      </td>

      <td>
        No more than three digits in a row can be consecutive or the same in the
        PIN code.
      </td>
    </tr>

    <tr>
      <td>
        <code>cannot\_specify\_pin\_code</code>
      </td>

      <td>
        Cannot specify a PIN code. You must leave the code empty, and the lock
        provider generates a PIN code.
      </td>
    </tr>

    <tr>
      <td>
        <code>pin\_code\_matches\_existing\_set</code>
      </td>

      <td>
        <p>
          If you specify a PIN code, it must match an existing set of PIN codes
          used in the account.
        </p>

        <p>
          For example, the PIN code could match the code assigned to a user in
          the system.
        </p>
      </td>
    </tr>

    <tr>
      <td>
        <code>start\_date\_in\_future</code>
      </td>

      <td>For time-bound codes, the start date must be in the future.</td>
    </tr>

    <tr>
      <td>
        <code>no\_ascending\_or\_descending\_sequence</code>
      </td>

      <td>PIN code cannot consist of a sequence of consecutive digits.</td>
    </tr>

    <tr>
      <td>
        <code>at\_least\_three\_unique\_digits</code>
      </td>

      <td>PIN code must contain at least three unique digits.</td>
    </tr>

    <tr>
      <td>
        <code>no\_all\_same\_digits</code>
      </td>

      <td>
        PIN code cannot consist entirely of the same repeated digit (for
        example, <code>1111</code> is invalid).
      </td>
    </tr>

    <tr>
      <td>
        <code>unique\_first\_four\_digits</code>
      </td>

      <td>The first four digits of the PIN code must all be distinct.</td>
    </tr>

    <tr>
      <td>
        <code>cannot\_contain\_089</code>
      </td>

      <td>
        <p>
          PIN code cannot contain the digits <code>0</code>, <code>8</code>, or{' '}
          <code>9</code>.
        </p>

        <p>
          For example, this restriction could apply to a cylinder lock that only
          includes the digits <code>1</code> to <code>7</code>.
        </p>
      </td>
    </tr>

    <tr>
      <td>
        <code>cannot\_contain\_0789</code>
      </td>

      <td>
        <p>
          PIN code cannot contain the digits <code>0</code>, <code>7</code>,{' '}
          <code>8</code>, or <code>9</code>.
        </p>

        <p>
          For example, this restriction could apply to a cylinder lock that only
          includes the digits <code>1</code> to <code>6</code>.
        </p>
      </td>
    </tr>

    <tr>
      <td>
        <code>name\_length</code>
      </td>

      <td>
        <p>Name of the code has some restrictions on length.</p>

        <p>
          When the <code>constraint\_type</code> is <code>name\_length</code>, the
          constraint object has one or two additional properties called{' '}
          <code>min\_length</code> and <code>max\_length</code> to specify the
          length constraints.
        </p>
      </td>
    </tr>

    <tr>
      <td>
        <code>name\_must\_be\_unique</code>
      </td>

      <td>Name of the code must be unique within the device.</td>
    </tr>
  </tbody>
</table>

***

## Provider-Specific Requirements

In addition to code constraints, some device providers have additional requirements for creating access codes.

### Timezone Configuration

Some device providers require you to configure the device's timezone before creating time-bound access codes. This is because these devices schedule access codes using device-local time, but their APIs do not report the device's timezone.

**Providers requiring timezone configuration:**

* **Ultraloq** — Must configure timezone using `/devices/report_provider_metadata` before creating time-bound access codes. See [Configuring Ultraloq Device Timezones](/device-and-system-integration-guides/ultraloq-locks/configuring-ultraloq-device-timezones).

<Info>
  Permanent access codes (codes without `starts_at` and `ends_at`) do not
  require timezone configuration, even on providers that require it for
  time-bound codes.
</Info>

**Detecting timezone requirement:**

Check for the provider-specific timezone warning in `device.warnings`:

<CodeGroup>
  ```javascript JavaScript theme={null}
  import { Seam } from 'seam'

  const seam = new Seam()

  const device = await seam.devices.get({
    device_id: 'your-device-id',
  })

  // Check for timezone warnings
  const timezoneWarnings = device.warnings.filter((w) =>
    w.warning_code.toLowerCase().includes('time_zone'),
  )

  if (timezoneWarnings.length > 0) {
    console.log('⚠️ Timezone configuration required for time-bound codes')
    console.log(`Warning: ${timezoneWarnings[0].message}`)
  }
  ```

  ```bash cURL theme={null}
  device=$(curl -X 'POST' \
    'https://connect.getseam.com/devices/get' \
    -H 'accept: application/json' \
    -H "Authorization: Bearer ${SEAM_API_KEY}" \
    -H 'Content-Type: application/json' \
    -d "{
      \"device_id\": \"your-device-id\"
    }")

  # Check for timezone warnings
  echo $device | jq '.device.warnings[] | select(.warning_code | test("time_zone"; "i"))'
  ```

  ```python Python theme={null}
  from seam import Seam

  seam = Seam()

  device = seam.devices.get(device_id="your-device-id")

  # Check for timezone warnings
  timezone_warnings = [
    w for w in device.warnings
    if "time_zone" in w.warning_code.lower()
  ]

  if timezone_warnings:
    print("⚠️ Timezone configuration required for time-bound codes")
    print(f"Warning: {timezone_warnings[0].message}")
  ```

  ```ruby Ruby theme={null}
  require "seam"

  seam = Seam.new()

  device = seam.devices.get(device_id: "your-device-id")

  # Check for timezone warnings
  timezone_warnings = device.warnings.select do |w|
    w.warning_code.downcase.include?("time_zone")
  end

  if timezone_warnings.any?
    puts "⚠️ Timezone configuration required for time-bound codes"
    puts "Warning: #{timezone_warnings[0].message}"
  end
  ```

  ```php PHP theme={null}
  <?php
  require 'vendor/autoload.php';

  use Seam\SeamClient;

  $seam = new SeamClient();

  $device = $seam->devices->get(device_id: "your-device-id");

  // Check for timezone warnings
  $timezoneWarnings = array_filter($device->warnings, function($w) {
    return stripos($w->warning_code, "time_zone") !== false;
  });

  if (count($timezoneWarnings) > 0) {
    echo "⚠️ Timezone configuration required for time-bound codes\n";
    echo "Warning: " . array_values($timezoneWarnings)[0]->message . "\n";
  }
  ```

  ```csharp C# theme={null}
  using Seam.Client;
  using System.Linq;

  var seam = new SeamClient();

  var device = seam.Devices.Get(deviceId: "your-device-id");

  // Check for timezone warnings
  var timezoneWarnings = device.Warnings
    .Where(w => w.WarningCode.ToLower().Contains("time_zone"))
    .ToList();

  if (timezoneWarnings.Any())
  {
    Console.WriteLine("⚠️ Timezone configuration required for time-bound codes");
    Console.WriteLine($"Warning: {timezoneWarnings[0].Message}");
  }
  ```

  ```java Java theme={null}
  import com.seam.api.Seam;
  import com.seam.api.types.Device;
  import java.util.stream.Collectors;

  Seam seam = Seam.builder().build();

  Device device = seam.devices().get(
    DevicesGetRequest.builder()
      .deviceId("your-device-id")
      .build()
  );

  // Check for timezone warnings
  var timezoneWarnings = device.getWarnings().stream()
    .filter(w -> w.getWarningCode().toLowerCase().contains("time_zone"))
    .collect(Collectors.toList());

  if (!timezoneWarnings.isEmpty()) {
    System.out.println("⚠️ Timezone configuration required for time-bound codes");
    System.out.println("Warning: " + timezoneWarnings.get(0).getMessage());
  }
  ```
</CodeGroup>

For devices requiring timezone configuration, attempting to create a time-bound access code without first setting the timezone will result in a validation error.