Bitcoin Concepts

What is OP_CAT and why does it matter?

OP_CAT is a re-enabled Bitcoin opcode that allows concatenation of data in script. On Fractal, OP_CAT powers secure smart contracts, recursive covenants, and modular logic across Bitcoin-native assets.

→ Learn about OP_CAT

What are Bitcoin covenants?

Covenants let you restrict how UTXOs can be spent — enabling things like vaults, decentralized governance, or time-locked contracts. Fractal supports expressive covenants through OP_CAT.

→ Learn more

What’s the difference between BRC-20, and Runes?

• BRC-20: Simple inscription-based token format that originated on Bitcoin, now supported natively on Fractal

• Runes: Lightweight, inscription-based token protocol supported on both Bitcoin and Fractal

All three standards are natively supported on Fractal.