openapi: 3.0.3
info:
  title: Unreal Speech API
  description: 'Unreal Speech is a low-cost, high-scale text-to-speech (TTS) API. It exposes a small REST surface: POST /stream for low-latency HTTP streaming of short text, POST /speech for synchronous MP3 output with word/sentence timestamps, and POST /synthesisTasks (with GET /synthesisTasks) for asynchronous long-form audio. All requests are authenticated with a Bearer API key issued from the dashboard. Note: the base host carries a version segment that has advanced over time (the Python SDK references api.v6, the live reference documents api.v7); paths are stable across versions.'
  version: v7
  contact:
    name: Unreal Speech
    url: https://unrealspeech.com
  termsOfService: https://unrealspeech.com/terms
servers:
- url: https://api.v7.unrealspeech.com
  description: Unreal Speech API (documented current host)
security:
- bearerAuth: []
tags:
- name: Speech
  description: Synchronous text-to-speech returning an MP3 and timestamp URLs.
paths:
  /speech:
    post:
      operationId: createSpeech
      tags:
      - Speech
      summary: Synthesize speech (synchronous)
      description: Converts up to 3,000 characters of text into speech and returns JSON containing an MP3 audio URL plus word- or sentence-level timestamp URLs. Use for medium-length, non-time-critical synthesis.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/SpeechRequest'
      responses:
        '200':
          description: Synthesis result with audio and timestamp URLs.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SpeechResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '429':
          $ref: '#/components/responses/RateLimited'
components:
  responses:
    Unauthorized:
      description: Missing or invalid API key.
    RateLimited:
      description: Too many requests - the per-plan request-rate limit was exceeded.
  schemas:
    SpeechResponse:
      type: object
      properties:
        OutputUri:
          type: string
          format: uri
          description: URL to the synthesized MP3 audio file.
        TimestampsUri:
          type: string
          format: uri
          description: URL to the JSON timestamps file.
    SpeechRequest:
      type: object
      required:
      - Text
      - VoiceId
      properties:
        Text:
          type: string
          description: The text to synthesize (up to 3,000 characters).
          maxLength: 3000
          example: This is a test.
        VoiceId:
          type: string
          description: The voice to use.
          enum:
          - Scarlett
          - Dan
          - Liv
          - Will
          - Amy
          default: Scarlett
        Bitrate:
          type: string
          description: Output audio bitrate.
          enum:
          - 320k
          - 256k
          - 192k
          - 128k
          - 64k
          - 32k
          default: 192k
        Speed:
          type: string
          description: Playback speed adjustment, from -1.0 (slower) to 1.0 (faster).
          default: '0'
        Pitch:
          type: string
          description: Voice pitch, from 0.5 to 1.5.
          default: '1'
        TimestampType:
          type: string
          description: Granularity of the returned timestamps.
          enum:
          - word
          - sentence
          default: sentence
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: 'API key issued from the Unreal Speech dashboard, sent as Authorization: Bearer <API_KEY>.'