> ## Documentation index
> Fetch the complete documentation index at: https://docs.htspilot.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Languages

> The two language settings of the HTS Pilot API - Accept-Language for labels and messages, and the answer language of a lookup, set with the language field of a classify request.

Two settings decide the language of what the API returns. `Accept-Language` is per request and governs labels and
messages. The answer language is per lookup and governs the text written for that lookup.

Supported languages: English (`en`), Vietnamese (`vi`), Japanese (`ja`) and Korean (`ko`).

## Accept-Language: the language of the reader

Send `Accept-Language` with one of the four codes. A tag with a region is read by its language (`en-US` is `en`),
quality values are honoured, and the first supported language wins. Without the header, or with no supported
language in it, the service answers in its default language. The answer names its language in
`Content-Language`.

```bash
curl https://htspilot.com/api/lookups/f4a2251d5dc941ec99f7d459e05082a5 \
  -H "X-API-Key: hts_EXAMPLE_KEY_REPLACE_ME" \
  -H "Accept-Language: ja"
```

What follows `Accept-Language`:

- error messages (`detail`);
- status and decision labels (`status_label`, `decision_label`), role labels, country names;
- review flags: the `message` of each entry of `review_flags` and of `result.flags`;
- the names of the checks, the disclaimer and the legal notes of a result;
- the Excel templates and the Excel results of a batch.

The machine values next to a label do not change with the language: `status`, `decision`, the `code` of a review
flag. Branch on those, show the labels.

## The answer language of a lookup

A lookup has a language of its own, returned as `language`. It is set when the lookup is created:

1. the `language` field of `POST /api/classify`, when it is sent (`en`, `vi`, `ja` or `ko`; a tag with a region
   is read by its language);
2. otherwise the language of the request, from `Accept-Language`.

A rerun (`POST /api/lookups/{lookup_id}/rerun`) keeps the language of the lookup it continues, unless the
request names another `language`.

```bash
curl -X POST https://htspilot.com/api/classify \
  -H "X-API-Key: hts_EXAMPLE_KEY_REPLACE_ME" \
  -H "Content-Type: application/json" \
  -d '{"description": "Stainless steel vacuum flask, 500 ml", "market": "US", "language": "ko"}'
```

What is written in the answer language, for every reader, whatever their `Accept-Language`:

- the written reasons for choosing or ruling out a code, the summary and the open uncertainties;
- the missing information (`missing_info`);
- the questions with their options (`result.questions`);
- the legal findings and the warnings.

So a lookup created in Korean reads in Korean to everyone, while its review flags and status labels appear in
the language of whoever reads it.

## Which follows which

| Part of a lookup | Follows |
| --- | --- |
| `status_label`, `decision_label` | The reader (`Accept-Language`) |
| `review_flags`, `result.flags` | The reader |
| Names of checks, disclaimer, legal notes | The reader |
| Reasons, summary, uncertainties | The lookup (`language`) |
| `missing_info`, `result.questions` and their options | The lookup |
| Legal findings, warnings | The lookup |
| Official tariff descriptions | Not translated: as published |

This changed: questions, missing information and legal findings used to follow `Accept-Language` on every read.
A client that relied on the header for them now sets `language` when it creates the lookup.

## Notes

- A product description can be written in English, Vietnamese, Japanese or Korean, whatever the answer language.
- Texts that live in the tariff data and the legal notes exist in Vietnamese and English; Japanese and Korean
  readers get the English text.
- An integration that stores results for one team should set `language` explicitly on every classify request, so
  the stored text does not depend on the headers of whichever client created it.