> For the complete documentation index, see [llms.txt](https://docs.wproofreader.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.wproofreader.com/v6.12.0/api-reference/detect-language-api.md).
# Detect language API
`detect_language` takes a text and returns a list of the most likely languages.
It is built on top of the open-source [Compact Language Detector 2 (CLD2)](https://github.com/CLD2Owners/cld2) library.
**Command name:** `detect_language`\
**Success status:** `200 OK`
### On this page
* [Common parameters](#common-parameters)
* [Parameters](#parameters)
* [Behavior notes](#behavior-notes)
* [Response schema](#response-schema)
* [Request examples](#request-examples)
* [Errors](#errors)
**Related**: [Overview](/v6.12.0/api-reference/overview.md), [Supported languages](/v6.12.0/features/supported-languages.md), [Why WProofreader auto detect language doesn't work for small piece of texts?](/v6.12.0/faq/technical/languages/why-wproofreader-auto-detect-language-doesnt-work-for-small-piece-of-texts.md)
### Common parameters
`cmd` selects the command to run.
| Name | Type | Required | Description |
| ----- | ------ | -------- | -------------------------- |
| `cmd` | string | Yes | Must be `detect_language`. |
These parameters work with any `cmd`.
| Name | Type | Required | Description |
| ----------- | ------ | ---------- | ----------------------------------------------------------------- |
| `serviceid` | string | Cloud only | Cloud API key. Required for Cloud requests. Not used on-premises. |
| `format` | string | No | Response format. Supported: `json` (default), `xml`. |
| `callback` | string | No | JSONP wrapper function name. Use only with `format=json`. |
See [Overview](/v6.12.0/api-reference/overview.md#common-parameters) for details.
### Parameters
These are parameters specific to `cmd=detect_language`.
{% hint style="warning" %}
`detect_language` does **not** support `short_answer`.
{% endhint %}
| Name | Type | Required | Description |
| -------- | ------ | -------- | ---------------------------------------------------------------------- |
| `text` | string | Yes | Text to detect the language for. |
| `locale` | string | No | Localization for `LangName`. Accepted formats: `es`, `es-ES`, `es_ES`. |
### Behavior notes
* `locale` affects only `LangName`. It does not affect detection.
* If the language cannot be detected, you still get `200 OK`.
* The response contains a single item with `LangShortCode=Unknown`.
* For better accuracy on long texts, split content into sentences.
* Run `detect_language` per sentence.
* At least 3 words in text is needed to detected the language. See the information [here](/v6.12.0/faq/technical/languages/why-wproofreader-auto-detect-language-doesnt-work-for-small-piece-of-texts.md).
### Response schema
The response contains language candidates.
Use `format` to switch between JSON and XML.
{% tabs %}
{% tab title="JSON" %}
```json
[
{
"LangShortCode": "en_US",
"LangName": "English (US)",
"Proportion": 0.98
}
]
```
{% endtab %}
{% tab title="XML" %}
```xml
en_US
English (US)
0.98
```
{% endtab %}
{% endtabs %}
* `LangShortCode` (string)\
Detected language code. See [Supported languages](/v6.12.0/features/supported-languages.md). Can also be `Unknown`.
* `LangName` (string)\
Human-readable language name. Localized using `locale` when provided.
* `Proportion` (number)\
Confidence / proportion of this language in the text. Higher means “more likely”.
### Request examples
#### Example: single language detected
Request:
{% tabs %}
{% tab title="GET" %}
```http
GET https://endpoint/api?cmd=detect_language&text=this%20sampl%20text%20demonstrates%20the%20work%20of%20the%20Web%20API%20service.
```
{% endtab %}
{% tab title="POST" %}
```http
POST https://endpoint/api
Content-Type: application/json
{
"cmd": "detect_language",
"text": "this sampl text demonstrates the work of the Web API service."
}
```
{% endtab %}
{% endtabs %}
Response (`200 OK`):
{% tabs %}
{% tab title="JSON" %}
```json
[
{
"LangShortCode": "en_US",
"LangName": "English (US)",
"Proportion": 0.98
}
]
```
{% endtab %}
{% tab title="XML" %}
```xml
en_US
English (US)
0.98
```
{% endtab %}
{% endtabs %}
#### Example: localized language name (`locale=es-ES`)
Request:
{% tabs %}
{% tab title="GET" %}
```http
GET https://endpoint/api?cmd=detect_language&locale=es-ES&text=this%20sampl%20text%20demonstrates%20the%20work%20of%20the%20Web%20API%20service.
```
{% endtab %}
{% tab title="POST" %}
```http
POST https://endpoint/api
Content-Type: application/json
{
"cmd": "detect_language",
"locale": "es-ES",
"text": "this sampl text demonstrates the work of the Web API service."
}
```
{% endtab %}
{% endtabs %}
Response (`200 OK`):
{% tabs %}
{% tab title="JSON" %}
```json
[
{
"LangShortCode": "en_US",
"LangName": "Inglés (Estados Unidos)",
"Proportion": 0.98
}
]
```
{% endtab %}
{% tab title="XML" %}
```xml
en_US
Inglés (Estados Unidos)
0.98
```
{% endtab %}
{% endtabs %}
#### Example: no language detected
Request:
{% tabs %}
{% tab title="GET" %}
```http
GET https://endpoint/api?cmd=detect_language&text=asdfghjkl
```
{% endtab %}
{% tab title="POST" %}
```http
POST https://endpoint/api
Content-Type: application/json
{
"cmd": "detect_language",
"text": "asdfghjkl"
}
```
{% endtab %}
{% endtabs %}
Response (`200 OK`):
{% tabs %}
{% tab title="JSON (default)" %}
```json
[
{
"LangShortCode": "Unknown",
"LangName": "Unknown",
"Proportion": 0.0
}
]
```
{% endtab %}
{% tab title="XML" %}
```xml
Unknown
Unknown
0
```
{% endtab %}
{% endtabs %}
### Errors
This command has no command-specific `4xx` errors.
When language detection fails, the response is still `200 OK` with `LangShortCode=Unknown`.
Common API errors (for example an invalid `serviceid`) use the shared error format from [Overview](/v6.12.0/api-reference/overview.md#errors).