---
title: "Subtitles"
method: POST
path: "/v1/subtitles/generate"
tags: ["Suprsonic"]
---

# Subtitles

`POST /v1/subtitles/generate`

## Request

- Base URL: `https://suprsonic.ai`
- URL: `https://suprsonic.ai/v1/subtitles/generate`
- Auth: HTTP bearer
- TypeScript: <https://skmtc.dev/suprsonic/apis/suprsonic-unified-agent-api/docs/v1/subtitles/generate/post.ts> (a function with typed inputs; its response is checked against the schema)

Generate SRT/VTT subtitles from audio or video. Returns the subtitles as SRT or VTT text with the language, duration and number of cues. Use to caption a video or an audio file. For a plain transcript use stt or transcribe. Cost: 2 credits, charged only when a call succeeds.

## Request body

- SubtitleRequest
  - `audio_url` string, required
  - `language` string
  - `format` string

## Response `200`

The call's envelope: success, data (the capability's result), metadata, and credits_used (0 when the call did not succeed).

- UnifiedResponse: Standard envelope for all unified API responses.
  - `success` boolean, required
  - `data` union
    - object
    - unknown[]
      - unknown
  - `error` UnifiedError: RFC 7807 problem detail for machine-actionable errors.
    - `type` string, required
    - `title` string, required
    - `status` integer, required
    - `detail` string, nullable
    - `is_retriable` boolean
    - `retry_after_seconds` integer, nullable
    - `alternative_action` string, nullable
    - `error_category` string
    - `caller_error` string, nullable
  - `metadata` UnifiedMetadata: Metadata included in every unified API response.
    - `provider_used` string, nullable
    - `providers_tried` string[]
    - `mode_used` string, nullable
    - `response_time_ms` integer
    - `request_id` string
    - `capability` string, nullable
    - `params` object, nullable
  - `credits_used` integer

## Other responses

- `401`: No API key, or one that was not found or is revoked.
- `402`: Not enough credits for this call. The error's alternative_action says where to add them.
- `403`: The account is restricted by a billing issue.
- `422`: Validation Error
- `429`: The key's rate limit is reached. The error's retry_after_seconds says when to try again.

## Changes

- **2026-11-01** `120f2dd4c855`: 7 info
  - added the optional property `detail/caller_error` to the response with the `401` status
  - added the optional property `detail/caller_error` to the response with the `402` status
  - added the optional property `detail/caller_error` to the response with the `403` status
  - added the optional property `detail/caller_error` to the response with the `429` status
  - …3 more
- **2026-10-23** `9edc3bfe1b9c`: 2 info
  - added the optional property `detail/items/ctx` to the response with the `422` status
  - added the optional property `detail/items/input` to the response with the `422` status
- **2026-10-19** `8134f9a5b206`: 2 breaking, 15 info
  - the response's body type changed from no type to `object` for status `200`
  - the `detail/items/` response's property type changed from no type to `object` for status `422`
  - api operation id `unified_subtitle_v1_subtitles_generate_post` removed and replaced with `subtitle`
  - api tag `Suprsonic` added
  - …13 more

[Operation history](https://skmtc.dev/suprsonic/apis/suprsonic-unified-agent-api/changes/v1/subtitles/generate/post.md)

---

[API](https://skmtc.dev/suprsonic/apis/suprsonic-unified-agent-api.md) - [All operations](https://skmtc.dev/suprsonic/apis/suprsonic-unified-agent-api/llms.txt) - [OpenAPI document](https://skmtc.dev/suprsonic/apis/suprsonic-unified-agent-api/revisions/120f2dd4c855?raw)