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Prerequisites

Sign up for a free Fish Audio account to get started with our API.
  1. Go to fish.audio/auth/signup
  2. Fill in your details to create an account, complete steps to verify your account.
  3. Log in to your account and navigate to the API section
Once you have an account, you’ll need an API key to authenticate your requests.
  1. Log in to your Fish Audio Dashboard
  2. Navigate to the API Keys section
  3. Click “Create New Key” and give it a descriptive name, set a expiration if desired
  4. Copy your key and store it securely
Keep your API key secret! Never commit it to version control or share it publicly.

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Recipe

Call asr.transcribe() with include_timestamps=True, then turn each ASRSegment into a numbered cue. Segment start / end are in seconds, so the only real work is formatting them — SRT wants HH:MM:SS,mmm (comma), WebVTT wants HH:MM:SS.mmm (dot). 
from fishaudio import FishAudio

client = FishAudio()


def to_srt_timestamp(seconds: float) -> str:
    """Format a time in seconds as an SRT timestamp: HH:MM:SS,mmm."""
    millis = round(seconds * 1000)
    hours, millis = divmod(millis, 3_600_000)
    minutes, millis = divmod(millis, 60_000)
    secs, millis = divmod(millis, 1000)
    return f"{hours:02d}:{minutes:02d}:{secs:02d},{millis:03d}"


with open("speech.wav", "rb") as f:
    result = client.asr.transcribe(audio=f.read(), include_timestamps=True)

# SRT: 1-based index, comma decimal separator, blank line between cues.
with open("captions.srt", "w", encoding="utf-8") as srt:
    for i, segment in enumerate(result.segments, start=1):
        start = to_srt_timestamp(segment.start)
        end = to_srt_timestamp(segment.end)
        srt.write(f"{i}\n{start} --> {end}\n{segment.text.strip()}\n\n")

# WebVTT: same cues, "WEBVTT" header, dot decimal separator.
with open("captions.vtt", "w", encoding="utf-8") as vtt:
    vtt.write("WEBVTT\n\n")
    for segment in result.segments:
        start = to_srt_timestamp(segment.start).replace(",", ".")
        end = to_srt_timestamp(segment.end).replace(",", ".")
        vtt.write(f"{start} --> {end}\n{segment.text.strip()}\n\n")

print(f"Wrote {len(result.segments)} cues to captions.srt and captions.vtt")
Both files share one timestamp helper — WebVTT is just the SRT formatting with , swapped for ., so there is no second formatter to keep in sync.
Pass language= (for example "en" or "zh") when you know it — explicit language selection sharpens segment boundaries, which keeps your cue timing tight.