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

Kraken v2 / Crypto.com-style subscribe frame.

Accepts two caller conventions per channel list:

1. **Plain strings** — channels are grouped under
   `params.<channel_key>` (default key `"channel"`).

       MethodParams.subscribe(["ticker", "book"], %{})
       # => %{"method" => "subscribe", "params" => %{"channel" => ["ticker", "book"]}}

2. **Single pre-shaped map** — the caller supplies the `params` object
   directly (Kraken v2 expects `{"channel": "ticker", "symbol": [...]}`).

       MethodParams.subscribe([%{"channel" => "ticker", "symbol" => ["BTC/USD"]}], %{})
       # => %{"method" => "subscribe",
       #      "params" => %{"channel" => "ticker", "symbol" => ["BTC/USD"]}}

Multiple maps per call return `{:error, :multiple_maps_not_supported}`;
lists that mix maps and strings return `{:error, :mixed_channel_types}`.
Both errors propagate verbatim through `CCXT.WS.Subscription.build_subscribe/3`.

Config keys:
- `:op_field` — default `"method"`
- `:args_field` — default `"params"`
- `:channel_key` — default `"channel"` (string-channel branch only)

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