# `CCXT.Signing.HmacSha256Headers`
[🔗](https://github.com/ZenHive/ccxt_client/blob/main/lib/ccxt/signing/hmac_sha256_headers.ex#L1)

HMAC-SHA256 headers signing pattern (Bybit-style).

Used by: Bybit, Bitget, Phemex, Poloniex, and ~30 other exchanges.

## How it works

1. Create payload: `timestamp + apiKey + recvWindow + body_or_query`
2. Sign with HMAC-SHA256
3. Add signature and auth headers to request

## Configuration

    signing: %{
      pattern: :hmac_sha256_headers,
      api_key_header: "X-BAPI-API-KEY",
      timestamp_header: "X-BAPI-TIMESTAMP",
      signature_header: "X-BAPI-SIGN",
      recv_window_header: "X-BAPI-RECV-WINDOW",
      recv_window: 5000,
      signature_encoding: :hex
    }

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