Inference APIs

Measured accuracy

ModelWord error rateCharacter error rateClips with no errorsEmpty transcriptsSpeed
Whisper Large v3
openai/whisper-large-v3
8.4%2.4%4 of 300 of 300.072× real time
Parakeet TDT 0.6B v3
nvidia/parakeet-tdt-0.6b-v3
11%3.3%4 of 300 of 300.053× real time

Good. Usable with light review. Expect to correct a word here and there, mostly names and numbers. The clips are clean, single-speaker read speech, so treat this as a best case for your own recordings. How we measured, and all 83 languages.

What a transcript looks like

The clip with the median error rate from the test, reference text against what the API returned.

SpokenНо за птиците, които все още приличат на динозаври, има много неща.
Whisper Large v3Но за птиците, които все още приличат на джинозаври, има много неща.
Parakeet (its median clip)Spoken: Сателитът беше изпратен в космоса от ракета. Учените използват телескопи в космоса, защото земната атмосфера изкривява част от светлината и изгледа ни.
Сателитът беше изпратен в космоса от ракета, учените използват телескопи в космоса, защото земната атмосфера изкривява част от светлината и изгледане.

Language detection

All 10 clips we sent without a language field were identified as Bulgarian. Auto-detection is safe here; sending language=bg still skips the detection step.

Which model for Bulgarian

Whisper Large v3 was more accurate on these clips (8.4% against 11%). Parakeet is faster, which matters mainly on long recordings. Both cost the same. Side by side.

Quickstart

The request is the OpenAI transcription request with a different base URL. language is optional.

cURL
curl https://api.inferenceapis.com/v1/audio/transcriptions \
  -H "Authorization: Bearer $INFERENCE_API_KEY" \
  -F "model=openai/whisper-large-v3" \
  -F "language=bg" \
  -F "file=@recording.mp3" \
  -F "response_format=verbose_json"
Python · openai SDK
import os
from openai import OpenAI

client = OpenAI(base_url="https://api.inferenceapis.com/v1", api_key=os.environ["INFERENCE_API_KEY"])
with open("recording.mp3", "rb") as f:
    r = client.audio.transcriptions.create(model="openai/whisper-large-v3", file=f, language="bg", response_format="verbose_json")
print(r.text)

Subtitles and timestamps

response_format=srt or vtt returns a subtitle file with cues of up to two lines, broken at sentence ends and pauses. verbose_json with timestamp_granularities[]=word returns a start and end time for every word if you want to build your own.

Cost

$0.002 per minute of audio on either model: $0.12 for an hour, $12 for a hundred hours. Duration is measured from the file you upload. There is no daily cap on minutes and no subscription; enough to run your own Bulgarian test.

FAQ

How accurate is Whisper for Bulgarian?

On 30 clean read-speech clips it made 8.4% word errors, about one word in 12. Usable with light review. Expect to correct a word here and there, mostly names and numbers. Real recordings with noise, accents or several speakers will score worse.

Does language auto-detection work for Bulgarian?

In our test, yes: all 10 clips sent without a language were identified as Bulgarian. Sending language=bg still saves the detection step on every request.

Whisper or Parakeet for Bulgarian?

On the same clips Whisper Large v3 scored 8.4% and Parakeet 11%. Whisper was more accurate here; Parakeet is faster, which matters mainly for long recordings. Both cost $0.002 per minute.

Can it translate Bulgarian speech to English?

The API returns Bulgarian text. For English, transcribe first and translate the text with a chat model on the same key.

Related languages: Macedonian (16%) · Serbian (21%) · Russian (5.8%)