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

# Transcribe audio

> Submit an audio file or URL to Mach-1 and inspect the resulting transcript, speaker attribution, and source evidence.

Mach-1 transcription converts a recording into text for review and further analysis. You can upload an audio file, provide an HTTPS audio URL, or connect a supported delivery source.

## Before you start

Open [AionCX Build](https://build.aioncx.com) and select the correct workspace. You need a key with submission and read access to send the recording and inspect the result. The [quickstart](https://docs.aioncx.com/quickstart.md) covers the browser steps.

Direct uploads accept WAV, MP3, and M4A. The current direct-audio boundary is 256 MiB and four hours. An audio URL must be reachable by the processing service and pass its destination checks. Discover the workspace receiver URL in Build → Developers or through MCP transport discovery.

## Send a recording

In **New request**, select an audio file or audio URL. Choose **No analysis** when you want transcription alone, or select the published analysis versions to run afterward.

Choose Standard or Reserved processing and connect your scoped key. Reserved processing starts in its overnight or weekend window. Send the request once and retain the admitted interaction ID.

For an application, use the direct receiver's `/v1/ingest/audio` or `/v1/ingest/audio-url` contract in the [REST reference](https://docs.aioncx.com/api-reference/overview.md). MCP can submit an audio URL; local audio bytes use the discovered direct upload endpoint.

## Inspect the transcript

Open the request and check its status before reading the transcript.

* Review the text and available speaker turns.
* Use source timing when supplied to locate the relevant part of the recording.
* Check which input and transcript revision you are reading.
* Confirm important names, amounts, dates, and commitments against the source.

Speaker attribution and timing can be absent. Plain supplied text remains an untimed passage. Treat missing information as missing rather than reconstructing it from character positions.

## Add analysis

Choose the [analysis](https://docs.aioncx.com/mach1/analysis.md) you need before submitting when transcription and analysis should run together. Analysis has its own charge per selected Definition. Existing transcript submissions skip transcription charges.

## Recover a request

For a timeout or lost response, reuse the original request and idempotency key. Processing may already have accepted the recording.

A request waiting for funding retains its identity. Add credit through Usage and follow the existing status. See [errors and retries](https://docs.aioncx.com/mach1/errors.md) for URL, size, permission, and funding failures.


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