# [REST API](https://zerossl.com/documentation/api "ZeroSSL Documentation") Download CA Certificate

## Download CA Certificate HTTPS GET

To download a CA certificate using the ZeroSSL API, use the `download` endpoint and pass the certificate identifier in the `{identifier}` URL parameter. The identifier can be either a numeric CA certificate ID or a SHA-1 hash.

The optional `{method}` parameter lets you choose the download format.

**API Request URL:**

```
api.zerossl.com/ca_certificates/{identifier}/download/{method}?access_key=...
```

**HTTPS GET Request Parameters:**

| Parameter | Description |
| --- | --- |
| `access_key` | **[Required]** Use this parameter to specify your API access key. |
| `{identifier}` | **[Required]** Use this parameter to specify the CA certificate identifier. Accepts either the numeric CA certificate ID or the SHA-1 hash of the certificate. |
| `{method}` | **[Optional]** Use this parameter to specify the response format for the download.<br><br>If no parameter or a non-supported value is provided, the default method is `zip`.<br><br>**Supported values:**<br>- `zip` (default)<br>- `json`<br>- `pem`<br>- `chain`<br>- `xml` |

#### API Responses based on `method` parameter:

`zip`:

If your API request is successful, the ZeroSSL API will return your CA certificate files wrapped in a ZIP-file.

`json`:

If your API request is successful, the ZeroSSL API will return your CA certificate files in JSON format. You will find an example API response below:

```
{
    "certificate_intermediate.crt": "-----BEGIN CERTIFICATE-----\n...\n-----END CERTIFICATE-----",
    "bundle_full.crt": "-----BEGIN CERTIFICATE-----\n...\n-----END CERTIFICATE-----",
}
```

**Response attributes:**

| Parameter | Description |
| --- | --- |
| `certificate_intermediate.crt` | Returns the CA certificate in PEM format. |
| `bundle_full.crt` | Returns the CA certificate bundle in PEM format. |

`pem`:

If your API request is successful, the ZeroSSL API will return the CA certificate in plain text PEM format.

`chain`:

If your API request is successful, the ZeroSSL API will return the CA certificate bundle in plain text format.

`xml`:

If your API request is successful, the ZeroSSL API will return your CA certificate resource representation in XML format. Note that key names with dots are converted to underscores (e.g. `certificate_intermediate.crt` becomes `certificate_intermediate_crt`).