# `CCXT.WS.Subscription.TypeSubscribe`
[🔗](https://github.com/ZenHive/ccxt_client/blob/main/lib/ccxt/ws/subscription/type_subscribe.ex#L1)

KuCoin/Coinbase-style subscribe frame keyed on a `"type"` field.

KuCoin single-topic form:

    %{"type" => "subscribe", "topic" => "/market/ticker:BTC-USDT"}

Coinbase dual-field form:

    %{
      "type"         => "subscribe",
      "product_ids"  => ["BTC-USD", "ETH-USD"],
      "channels"     => ["matches"]
    }

The dual-field form is selected by setting `config[:channels_field]` to
`"channels"` (or similar); in that case `args_field` receives the market
id list and `channels_field` receives the channel name (wrapped in a
single-element list when the field is literally `"channels"`, otherwise
bare).

Config keys:
- `:op_field` — default `"type"`
- `:args_field` — default `"topic"`; Coinbase sets `"product_ids"`
- `:args_format` — `:string` (KuCoin default) or `:string_list` for arrays
- `:channels_field` — when set, activates the dual-field shape
- `:channel_name` — the channel name placed under `channels_field`

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*Consult [api-reference.md](api-reference.md) for complete listing*