multilingual transcription service api

Here’s a practical blueprint for a multilingual transcription service API.

What it should do

A good API typically supports:

• Speech-to-text for audio/video
• Multiple languages
• Language detection when unknown
• Timestamps for words/sentences
• Speaker diarization if needed
• Confidence scores
• Batch and streaming modes
• Translation optionally, if you want transcript output in a single language

---

Suggested API design

1) Upload audio

POST /v1/transcriptions

Request

• file: audio/video file
• language: optional, e.g. en, es, fr
• detect_language: boolean
• diarization: boolean
• format: json | srt | vtt | txt
• model: optional, e.g. general, phone_call, meeting

Example response

{
  "id": "tr_12345",
  "status": "queued",
  "language_detected": null
}

---

2) Check job status

GET /v1/transcriptions/{id}

Response

{
  "id": "tr_12345",
  "status": "completed",
  "language_detected": "es",
  "duration_seconds": 312.4,
  "transcript": "Hola, ¿cómo estás?",
  "segments": [
    {
      "start": 0.0,
      "end": 2.1,
      "speaker": "A",
      "text": "Hola, "
    },
    {
      "start": 2.1,
      "end": 4.0,
      "speaker": "A",
      "text": "¿cómo estás?"
    }
  ]
}

---

3) Download transcript

GET /v1/transcriptions/{id}/download?format=srt

---

Multilingual features to include

Language support

• Explicit language input: language=ar
• Auto-detection: detect_language=true
• Mixed-language transcription: return per-segment language tags

Example:

{
  "segments": [
    { "start": 0.0, "end": 1.2, "language": "en", "text": "Hello" },
    { "start": 1.2, "end": 3.0, "language": "fr", "text": "Bonjour" }
  ]
}

Translation option

If you want transcripts in English regardless of source language:

• translate_to=en

---

Common endpoints

• POST /v1/transcriptions
• GET /v1/transcriptions/{id}
• GET /v1/transcriptions/{id}/result
• DELETE /v1/transcriptions/{id}
• GET /v1/languages
• POST /v1/transcriptions/stream for live audio

---

Recommended response fields

• id
• status
• language_detected
• confidence
• duration_seconds
• transcript
• segments
• words
• speaker_labels
• error

---

Security

• API key auth: Authorization: Bearer <token>
• Rate limiting
• Signed upload URLs for large files
• Encryption at rest and in transit

---

Example cURL

curl -X POST https://api.example.com/v1/transcriptions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "file=@meeting.mp3" \
  -F "detect_language=true" \
  -F "diarization=true"

---

If you want, I can also provide:

1. a full OpenAPI/Swagger spec,
2. a FastAPI implementation, or
3. a database schema and job queue design for this API.