> ## Documentation Index
> Fetch the complete documentation index at: https://docs.aircaps.com/llms.txt
> Use this file to discover all available pages before exploring further.

# AirCaps API

> Speech-to-text for English: live streaming and speaker-labelled batch transcription.

The AirCaps API turns English speech into text with two models:

| Model | ID | Use it for |
| - | - | - |
| **A5S Async v1** | `a5s-async-v1` | Recorded audio and video: speaker labels, word timestamps, subtitles |
| **A5S v2 Streaming** | `a5s-v2-streaming` | Live audio: captions as people speak |

One API key works for both. Base URL: `https://api.aircaps.com/v1`

**Every account includes 5 hours of free usage**, shared by both models. For pricing, higher usage limits or concurrency, or a dedicated deployment, [talk to sales](https://research.aircaps.com/contact).

Both models transcribe **English** today. Multilingual support is planned and will be available soon.

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">Transcribe a file in five minutes.</Card>
  <Card title="API keys" icon="key" href="/authentication">Create and use a key.</Card>
  <Card title="Batch transcription" icon="file-audio" href="/guides/async-transcription">Uploads, URLs, polling and webhooks.</Card>
  <Card title="Live streaming" icon="microphone" href="/guides/streaming">The realtime WebSocket protocol.</Card>
</CardGroup>

<Card title="Talk to sales" icon="handshake" href="https://research.aircaps.com/contact">Pricing, higher limits and concurrency, model access, and dedicated deployments.</Card>

<Tip>Try both models without code in the [Playground](https://playground.aircaps.com/playground).</Tip>


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