Language Models
X

xAI's speech-to-text API costs $0.10 an hour in batch, and moved to 2.0 on 2 October

2026/10/13

xAI's Speech to Text is a transcription API covering 25 languages⁠[1]. It works in two modes: batch, where a recording is sent as a whole, and streaming, where audio is sent as it plays⁠[1].

It costs $0.10 per hour of audio in batch and $0.20 per hour in streaming⁠[2]. In the same Voice API, Speech to Speech for spoken conversation costs $0.08 per minute, and Text to Speech costs $15 per million characters⁠[2].

grok-voice-transcribe-2.0 was added on 17 September⁠[1]. It is also the model used when none is specified⁠[1].

grok-voice-transcribe-1.0 reached end of life on 2 October⁠[1]. Requests that name it are served by 2.0 at the same price⁠[1]. According to the release notes, 2.0 is more accurate⁠[1].

vad_threshold is the threshold of the voice activity detection that skips audio without speech⁠[1]. It can be set in both batch and streaming⁠[1]. Lower values make quieter or noisier speech, such as narrowband telephone audio, easier to transcribe, and 0 turns the detection off⁠[1].

Streaming also supports Smart Turn⁠[1]. With smart_turn enabled, a machine learning model predicts at each silence whether the speaker has finished, which reduces false cuts during dictation, number sequences and pauses mid-sentence⁠[1]. smart_turn_timeout sets the longest silence allowed before the turn ends anyway⁠[1].