ASR API Reference

The Shisa ASR API transcribes base64-encoded audio into text with a single JSON request. This page documents the endpoint, its request parameters, the success response, and error handling.

Endpoint

POST https://api.shisa.ai/asr/srt/audio_llm

Authenticate with a bearer token carrying the ASR-specific shsk: prefix:

Authorization: Bearer YOUR_API_KEY

The request body is JSON and the server auto-detects the audio format from its binary header.

Request parameters

Parameter	Type	Required	Description
audio	string	Required	Base64-encoded audio data (WAV, OGG, MP3, or FLAC).
language	string	Optional	Language code (e.g. "ja", "en"). Omit for automatic language detection (LID).
hotwords	string[]	Optional	Array of words/phrases to boost recognition accuracy for domain-specific terms.
temperature	float	Optional	Sampling temperature. Lower values make output more deterministic. Default: 0.0.
top_p	float	Optional	Nucleus sampling parameter. Controls diversity of output. Default: 0.85.
frequency_penalty	float	Optional	Penalizes frequent tokens to reduce repetition. Default: 0.5.
repetition_penalty	float	Optional	Penalizes token repetition; values above 1.0 discourage repetition. Default: 1.05.
vad	integer	Optional	Voice activity detection mode. Default: 1.

note

Only audio is required. Language is auto-detected, and the tuning parameters use sensible defaults — you can send the minimal request shown in the Quickstart and add parameters only as needed.

Success response

A successful request returns a JSON object with the transcription, the detected or specified language, and a confidence score:

{
  "text": "こんにちは、シサAIです。",
  "language": "ja",
  "confidence": 0.98
}

Field	Description
text	The transcribed text from the audio.
language	The detected or specified language code.
confidence	Transcription confidence score, from 0 to 1.

Error handling

Errors return a JSON object with an HTTP-style code and a human-readable error message:

{
  "code": 400,
  "error": "No audio data provided"
}

401 authentication error

Returned when the API key is missing, invalid, or expired. Check that your Authorization header includes a valid token with the shsk: prefix.

{
  "context": ["authMiddleware"],
  "code": 104,
  "name": "ErrAuthenticationFailed",
  "error": "Authentication error: Invalid token"
}

Error codes

Code	Cause	Error message
400	Missing audio field or audio decodes to empty	No audio data provided
400	Not base64 encoded or base64 decode fails	Invalid base64 audio data
400	Unsupported audio format	Unsupported audio format
500	Transcription services not ready	Transcription service not available
500	Backend failure	Transcription failed: ...

Next steps

• Make a working request in the Quickstart.
• Review supported formats and the 97 detectable languages in Audio & languages.
• See how usage is billed on Pricing.