# Detect language

> POST /ai_agent/checklanguage. Identify the language of text or HTML without translating it.

Source: https://www.fluentc.ai/docs/api/detect-language/

```http
POST https://api.fluentc.ai/ai_agent/checklanguage
```

Identifies the language of `input` and reports how confident the detection is. Use it when you need to know the language before you decide what to do, for example to route a support ticket. If you only want a translation, skip this call: [Translate](https://www.fluentc.ai/docs/api/translate.md) works out the source language when you leave `source_language` out.

## Request

Headers are the same as every endpoint: `Authorization` with your key and `Content-Type: application/json`.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `input` | string | Yes | The text or HTML to analyse. |
| `input_format` | string | Yes | `text` or `html`. `json` is not accepted. |

```bash
curl -X POST https://api.fluentc.ai/ai_agent/checklanguage \
  -H "Authorization: $FLUENTC_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "input": "Bonjour, comment allez-vous?",
    "input_format": "text"
  }'
```

## Response

`200 OK`

```json
{
  "detected_language": "fr",
  "confidence": 0.99
}
```

| Field | Type | Description |
| --- | --- | --- |
| `detected_language` | string | The language code, in the same format as `target_language`. |
| `confidence` | number | From 0 to 1. Higher is more certain. |

Decide in your own code what to do below a confidence threshold you choose, for example to ask a person to check.

## Errors

| Status | Message | Fix |
| --- | --- | --- |
| `422` | `Input is missing` | Send a non-empty `input`. |
| `422` | `Invalid or missing input format. Allowed formats: text, html` | Set `input_format` to `text` or `html`. |

Key and account errors are covered in [Authentication](https://www.fluentc.ai/docs/authentication.md). All error shapes are on [Errors](https://www.fluentc.ai/docs/api/errors.md).