> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-mintlify-3a82795f.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# HTTP(S) dictionary source

> Configure an HTTP or HTTPS endpoint as a dictionary source in ClickHouse.

Working with an HTTP(S) server depends on [how the dictionary is stored in memory](/reference/statements/create/dictionary/layouts/overview). If the dictionary is stored using `cache` and `complex_key_cache`, ClickHouse requests the necessary keys by sending a request via the `POST` method.

Example of settings:

<Tabs>
  <Tab title="DDL">
    ```sql theme={null}
    SOURCE(HTTP(
        url 'http://[::1]/os.tsv'
        format 'TabSeparated'
        credentials(user 'user' password 'password')
        headers(header(name 'API-KEY' value 'key'))
    ))
    ```
  </Tab>

  <Tab title="Configuration file">
    ```xml theme={null}
    <source>
        <http>
            <url>http://[::1]/os.tsv</url>
            <format>TabSeparated</format>
            <credentials>
                <user>user</user>
                <password>password</password>
            </credentials>
            <headers>
                <header>
                    <name>API-KEY</name>
                    <value>key</value>
                </header>
            </headers>
        </http>
    </source>
    ```
  </Tab>
</Tabs>

<br />

In order for ClickHouse to access an HTTPS resource, you must [configure openSSL](/reference/settings/server-settings/settings#openssl) in the server configuration.

Setting fields:

| Setting       | Description                                                                                |
| ------------- | ------------------------------------------------------------------------------------------ |
| `url`         | The source URL.                                                                            |
| `format`      | The file format. All the formats described in [Formats](/reference/formats) are supported. |
| `credentials` | Basic HTTP authentication. Optional.                                                       |
| `user`        | Username required for the authentication.                                                  |
| `password`    | Password required for the authentication.                                                  |
| `headers`     | All custom HTTP headers entries used for the HTTP request. Optional.                       |
| `header`      | Single HTTP header entry.                                                                  |
| `name`        | Identifier name used for the header send on the request.                                   |
| `value`       | Value set for a specific identifier name.                                                  |

When creating a dictionary using the DDL command (`CREATE DICTIONARY ...`) remote hosts for HTTP dictionaries are checked against the contents of `remote_url_allow_hosts` section from config to prevent database users to access arbitrary HTTP server.