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Consensus and Fee Model

Consensus​

On the OP_CAT Layer, we use Proof of Work (POW), the most proven consensus model used by Bitcoin itself, but with a few key differences:

  • Merged mining: Allows Bitcoin miners to simultaneously mine the OP_CAT Layer
  • FIFO mempool: First-in, first-out transaction ordering with no Replace-by-Fee (RBF)

Fee Model​

The OP_CAT Layer, as a Bitcoin execution layer, has a unique fee model with the following characteristics:

  • Transaction/Gas fees: Every transaction on the OP_CAT Layer requires BTC as transaction fees. It is the wrapped version of Bitcoin at a 1:1 ratio. It mirrors Bitcoin's 21 million supply cap and 8 decimal places. The minimum unit is also called a satoshi (or sat for short). No new token is needed to pay transaction fees.
  • No priority fees: Transactions are accepted in FIFO (first-in, first-out) order with no Replace-by-Fee (RBF), as in the original Bitcoin design.
  • Miner rewards: When miners produce a valid block, they receive only the transaction fees from that block with zero block reward.
  • Genesis allocation: All BTC tokens are minted at genesis and locked in a bridge smart contract.
  • Bridge-based release: Tokens can only be released from the contract by bridging an equivalent amount of BTC from the Bitcoin network to the OP_CAT Layer. For more details, see the bridge mechanism.