Bitcoin has always included a powerful scripting language that can lock coins to conditions beyond “one signature unlocks the funds.” With Script, you can combine multiple keys, timelocks, hash preimages, and complex logical branches. In practice, however, Script has rarely been used directly because it is difficult to write correctly, mistakes can permanently lock funds, and the resulting code is nearly impossible to analyze at a glance.

Miniscript (BIP-379) was introduced by Pieter Wuille and collaborators as “a language for writing Bitcoin Scripts in a structured way, enabling analysis, composition, and generic signing.” It solves the usability and safety problems of raw Script while retaining full compatibility with today’s Bitcoin rules.

At its heart, Miniscript is like a box of Lego bricks for Bitcoin spending rules. Each brick is a small, well-defined condition, such as a key must sign, a time must pass, or a secret must be revealed. Bricks can be swapped for other components, allowing flexible construction of alternative spending paths. By combining them with logical operators such as AND, OR, and thresholds, you can build policies that are as simple or as complex as needed. Most importantly, Miniscript policies are analyzable: wallets can check in advance who can spend and under what conditions, reducing the risk of coins being locked by an invalid script.

This structured approach makes it possible to safely express policies such as:

With Miniscript, policies go beyond single-sig or simple multisig. You can define rules such as “A and B together can spend immediately, or C alone after 1 year,” or “2-of-3 required now, but 1-of-3 after 6 months.” These flexible conditions enable practical use cases such as inheritance planning, layered business treasuries, and emergency recovery, making advanced security accessible to everyday Bitcoin users. Importantly, all Miniscript policies are enforced directly on-chain in Bitcoin itself and do not require any additional trust assumptions beyond the Bitcoin network.