TikTok Caption Translation API

Endpoint facts

Method

GET

API path

/tiktok/mobile/translation/description

Auth

apiKey

Credits

8 credits/request

Charged on

Successful 2xx responses only

Platform

TikTok

Execution

Managed browser rendering where the target needs it

Response schema

#/definitions/tiktokmobile.translationDescriptionResponseDoc

How this endpoint behaves

Calls the app's own caption-translation route — POST /aweme/v1/translation/description/ — and returns the translated caption. The route was captured from the running 47.4.3 app over mitmproxy (chained to a US Surge exit) and then reproduced end-to-end with the device-backed signer, so the request body and the response shape below are measured, not inferred.

Requires device-backed request signing. The route validates signature values, so the deployment must have the device-backed signer configured (TIKTOK_MOBILE_SIGNER_URL). Without it the endpoint fails closed with a typed error instead of returning a stub.

Query parameters:

• item_id: required. The numeric video id whose caption is translated. A non-numeric id is rejected before any upstream call.
• target_lang: optional, default en. A language code in the app's own format (en, ja, pt-BR, zh-Hans, ...). Forwarded as-is.

The app's request is a form POST carrying item_id, target_lang and translation_protocol=2; this endpoint sends exactly that body.

Response fields:

• translated_client_text.client_text_v2.markup_text: the translated caption in the app's markup, where line breaks are <br> and hashtags are wrapped as <h id="N">#tag</h>. Returned unchanged.
• translated_client_text.client_text_v2.text_extra: opaque hashtag records (hashtag_id, hashtag_name, is_commerce, tag_id), kept as any so nothing is lost.
• translated_client_text.translation_protocol: measured 2.
• text: convenience projection of markup_text with <br> turned into newlines and the hashtag wrappers stripped.
• format, variant, extra, log_pb, perf_metrics, status_code, status_msg: the upstream envelope, kept verbatim.
• host, fetched_at, item_id, target_lang: request echo.

Measured 2026-10-21 with the device-backed signer:

• Japanese caption → target_lang=en: HTTP 200, 3,121 B, status_code 0, format 1, a 1,617-character English markup_text and 4 text_extra hashtags.
• An already-English caption → target_lang=en: status_code 3048002 "same source language and target language"; checkStatus maps a non-zero status_code to a typed upstream error, so this is reported as an error rather than as an empty translation.

Example request:

GET /api/v1/tiktok/mobile/translation/description?item_id=7650052642089225493&target_lang=en

Example response (truncated):

{
  "code": 200,
  "msg": "OK",
  "data": {
    "item_id": "7650052642089225493",
    "target_lang": "en",
    "translated_client_text": {
      "client_text_v2": {
        "markup_text": "Japan's most popular ramen stall...<br><br>...<h id=\"2\">#東京グルメ</h>",
        "text_extra": [
          {"hashtag_id": "1611500018038786", "hashtag_name": "東京グルメ", "is_commerce": false, "tag_id": "2"}
        ]
      },
      "translation_protocol": 2
    },
    "text": "Japan's most popular ramen stall...\n\n...#東京グルメ",
    "format": 1,
    "status_code": 0,
    "host": "aggr32-normal.tiktokv.us"
  }
}

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