High-Assurance
Bitcoin Contracts
Simplicity is a next-generation smart contracting language for Bitcoin, designed for verifiable security, financial correctness, and high-value applications.
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High-Assurance
Simplicity is a next-generation smart contracting language for Bitcoin, designed for verifiable security, financial correctness, and high-value applications.
Every major financial market depends on correctness. But the multi-billion dollar failures of the past all relied on hope. Simplicity is the only smart contracting language to offer certainty by allowing developers to mathematically prove exactly how a contract will behave before it's deployed.
No more economic exploits
No more re-entrancy and logic bugs
Predictable resource costs
High-assurance smart contracts for BitcoinSimplicity complements Bitcoin Script with a low-level language that's expressive enough for advanced covenants and financial instruments while being formally verifiable for absolute predictability. Developers write SimplicityHL, full nodes execute Simplicity. Learn more
sig := const 0xe907831f80848d1069a5371b402410364bdf1c5f8307b0084c55f1ce2dca821525f66a4a85ea8b71e482a74f382d2ce5ebeee8fdb2172f477df4900d310536c0 : 1 -> 2^512 pk := const 0xf9308a019258c31049344f85f89d5229b531c845836f99b08601f113bce036f9 : 1 -> 2^256 msg := const 0x0000000000000000000000000000000000000000000000000000000000000000 : 1 -> 2^256 in := pair (pair pk msg) sig : 1 -> 2^512 * 2^512 out := jet_bip_0340_verify : 2^512 * 2^512 -> 1 main := comp in out
Simplicity isn't just powerful—it's fun! If you know Rust, you already know Simplicity. It's straightforward, no steep learning curves.
No more complicated, messy scripts. Simplicity makes covenants and conditions clean, clear, and easy to understand.
You write in SimplicityHL, your full node runs Simplicity. It's that easy—elegant code, simple execution.
Gas costs can spike, inviting expensive runtime surprises.
Resource costs are fully bounded and known before execution.
Hard to prove safe, meaning hacks are frequent.
Formally verifiable — mathematically prove contract behaviour.
Lots of components; large attack surface.
Minimal trusted codebase; drastically reduced attack surface.
Ambiguous and unfocused "world computer" claims.
Purpose-built for Bitcoin — covenants and financial instruments.
Since Simplicity contracts are auditable and proveable before deployment, Simplicity offers unprecedented transparency and compliance assurance for financial institutions. Build programmable capital markets, issue assets, and settle trades—all on Bitcoin's most secure sidechain, Liquid.
“Simplicity’s strength comes from deep, foundational principles in type theory. SimplicityHL, as a frontend, abstracts away much of the complexity, allowing users to write smart contracts, with minimal code and high reliability. SimplicityHL keeps the computer science fundamentals close enough that you can reason about it formally when needed.”
- Andrew Poelstra
Adapt our extensive library of existing contracts to your needs, or start writing your own. Available on Liquid with multi-asset support and Bitcoin’s Mutinynet.
