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

# Transcripts topic

> Stream the transcript of each new ATC transmission that passes your filters over the live WebSocket.

Streams the transcript of each new ATC transmission that passes the subscription's filters, as soon as it is processed. See [Connect](https://enhancedradar.com/docs/api/docs/api/api-reference/live/connect.md) for the message format.

## Parameters

At least one parameter is required.

**callsign** `string`

Only transmissions attributed to this flight, by ICAO callsign.

**facility\_id** `string`

Only transmissions on this facility's available channels.

**atc\_channel\_ids** `integer[]`

Array of channel ids, e.g. `[4, 7, 8]`. Only transmissions on these channels. With `facility_id`, only the channels in both.

**airline\_id** `integer`

Only transmissions attributed to a flight of this airline, from [List airlines](https://enhancedradar.com/docs/api/docs/api/api-reference/airlines/list.md).

```json theme={null}
{"action": "subscribe", "subscription_topic": "transcripts", "params": {"facility_id": "3667d976-1566-4887-ae34-c024d92f46c7"}}
```

## Updates

Each update's `data` has the same fields as one entry of `transcripts` in [List transcripts](https://enhancedradar.com/docs/api/docs/api/api-reference/transcripts/list.md), without `search_score`.

* Only transmissions on available channels that have a transcript are sent.
* `callsigns` and the `callsign` and `airline_id` filters use the flights the transmission was attributed to when it was processed; a later correction does not send the transmission again.
* Use `received_at` to order transcripts.
* Use [Get transcript audio](https://enhancedradar.com/docs/api/docs/api/api-reference/transcripts/audio.md) for a transmission's audio.

## Billing

Subscribing is free. Each transcript sent is charged as one `transcript`, at \$0.03. See [Pricing](https://enhancedradar.com/docs/api/docs/api/pricing.md) and [Billing](https://enhancedradar.com/docs/api/docs/api/concepts/billing.md).

## Refusals

The subscription is refused when no parameter was given, or when a filter is invalid, such as an unknown `airline_id`, a facility that is not covered, an unavailable channel, or `atc_channel_ids` with none on `facility_id`.


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