# `engine:`

In the code example below a full fledged example of a YAML setup from a dummy engine is shown. Most of the options have a default value or even are optional.

Hint

A few more options are possible, but they are pretty specific to some engines (Engine Implementations).

    - name: example engine
      engine: example
      shortcut: demo
      base_url: 'https://{language}.example.com/'
      send_accept_language_header: false
      categories: general
      timeout: 3.0
      api_key: 'apikey'
      disabled: false
      language: en_US
      tokens: [ 'my-secret-token' ]
      weight: 1
      display_error_messages: true
      about:
         website: https://example.com
         wikidata_id: Q306656
         official_api_documentation: https://example.com/api-doc
         use_official_api: true
         require_api_key: true
         results: HTML

      # overwrite values from section 'outgoing:'
      enable_http2: false
      retries: 1
      max_connections: 100
      max_keepalive_connections: 10
      keepalive_expiry: 5.0
      using_tor_proxy: false
      proxies:
        http:
          - http://proxy1:8080
          - http://proxy2:8080
        https:
          - http://proxy1:8080
          - http://proxy2:8080
          - socks5://user:password@proxy3:1080
          - socks5h://user:password@proxy4:1080

      # other network settings
      enable_http: false
      retry_on_http_error: true # or 403 or [404, 429]

`name` :

  Name that will be used across SearXNG to define this engine. In settings, on the result page…

`engine` :

  Name of the python file used to handle requests and responses to and from this search engine.

`shortcut` :

  Code used to execute bang requests (in this case using `!bi`)

`base_url` optional

  Part of the URL that should be stable across every request. Can be useful to use multiple sites using only one engine, or updating the site URL without touching at the code.

`send_accept_language_header` :

  Several engines that support languages (or regions) deal with the HTTP header `Accept-Language` to build a response that fits to the locale. When this option is activated, the language (locale) that is selected by the user is used to build and send a `Accept-Language` header in the request to the origin search engine.

`categories` optional

  Specifies to which categories the engine should be added. Engines can be assigned to multiple categories.

  Categories can be shown as tabs (categories_as_tabs:) in the UI. A search in a tab (in the UI) will query all engines that are active in this tab. In the preferences page (`/preferences`) – under engines – users can select what engine should be active when querying in this tab.

  Alternatively, !bang can be used to search all engines in a category, regardless of whether they are active or not, or whether they are in a tab of the UI or not. For example, `!dictionaries` can be used to query all search engines in that category (group).

`timeout` optional

  Timeout of the search with the current search engine. Overwrites `request_timeout` from outgoing:. Be careful, it will modify the global timeout of SearXNG.

`api_key` optional

  In a few cases, using an API needs the use of a secret key. How to obtain them is described in the file.

`disabled` optional

  To disable by default the engine, but not deleting it. It will allow the user to manually activate it in the settings.

`inactive`: optional

  Remove the engine from the settings (disabled & removed).

`language` optional

  If you want to use another language for a specific engine, you can define it by using the ISO code of language (and region), like `fr`, `en-US`, `de-DE`.

`tokens` optional

  A list of secret tokens to make this engine private, more details see Private Engines (tokens).

`weight` default `1`

  Weighting of the results of this engine.

`display_error_messages` default `true`

  When an engine returns an error, the message is displayed on the user interface.

`network` optional

  Use the network configuration from another engine. In addition, there are two default networks:

  - `ipv4` set `local_addresses` to `0.0.0.0` (use only IPv4 local addresses)

  - `ipv6` set `local_addresses` to `::` (use only IPv6 local addresses)

`enable_http` optional

  Enable HTTP for this engine (by default only HTTPS is enabled).

`retry_on_http_error` optional

  Retry request on some HTTP status code.

  Example:

  - `true` : on HTTP status code between 400 and 599.

  - `403` : on HTTP status code 403.

  - `[403, 429]`: on HTTP status code 403 and 429.

`proxies` :

  Overwrites proxy settings from outgoing:.

`using_tor_proxy` :

  Using tor proxy (`true`) or not (`false`) for this engine. The default is taken from `using_tor_proxy` of the outgoing:.

`max_keepalive_connection#s` :
  Pool limit configuration, overwrites value `pool_maxsize` from

    outgoing: for this engine.

`max_connections` :

  Pool limit configuration, overwrites value `pool_connections` from outgoing: for this engine.

`keepalive_expiry` :

  Pool limit configuration, overwrites value `keepalive_expiry` from outgoing: for this engine.

## Private Engines (`tokens`)

Administrators might find themselves wanting to limit access to some of the enabled engines on their instances. It might be because they do not want to expose some private information through Offline Engines. Or they would rather share engines only with their trusted friends or colleagues.

To solve this issue the concept of private engines exists.

A new option was added to engines named tokens. It expects a list of strings. If the user making a request presents one of the tokens of an engine, they can access information about the engine and make search requests.

Example configuration to restrict access to the Arch Linux Wiki engine:

    - name: arch linux wiki
      engine: archlinux
      shortcut: al
      tokens: [ 'my-secret-token' ]

Unless a user has configured the right token, the engine is going to be hidden from them. It is not going to be included in the list of engines on the Preferences page and in the output of /config REST API call.

Tokens can be added to one’s configuration on the Preferences page under “Engine tokens”. The input expects a comma separated list of strings.

The distribution of the tokens from the administrator to the users is not carved in stone. As providing access to such engines implies that the admin knows and trusts the user, we do not see necessary to come up with a strict process. Instead, we would like to add guidelines to the documentation of the feature.

## Example: Multilingual Search

SearXNG does not support true multilingual search. You have to use the language prefix in your search query when searching in a different language.

But there is a workaround: By adding a new search engine with a different language, SearXNG will search in your default and other language.

Example configuration in settings.yml for a German and English speaker:

    search:
        default_lang : "de"
        ...

    engines:
      - name : google english
        engine : google
        language : en
        ...

When searching, the default google engine will return German results and “google english” will return English results.