What if you could take a smart contract, written using a modern language like Python, TypeScript, or Scala, and run it on Bitcoin without modifying Bitcoin itself?
Thanks to a novel compilation pipeline being developed at Input | Output (IO), that idea is becoming a reality. By combining a serialized smart contract format (Untyped Plutus Core – UPLC), a clever interpreter architecture (Control, Environment, Continuation (CEK) machine), and a widely supported open-source reduced instruction set architecture (RISC-V), IO is building a connection from the expressive world of Cardano smart contracts to the solid base layer of Bitcoin. At the center of this is BitVMX, an optimistic verification system for Bitcoin that leverages RISC-V to safely execute off-chain logic.
While Bitcoin is secure, simple, and stable, its scripting language is extremely limited. That’s a feature, not a bug, but it makes decentralized finance (DeFi) and complex applications hard to build natively.
So instead of rewriting Bitcoin, what if it had an optimistic execution environment where rich logic can run off-chain, and Bitcoin only gets involved when there’s a disagreement?
That’s exactly what BitVMX does, and its pipeline makes it easy to feed real smart contracts into this environment.
This architecture enables developers to reuse the existing Cardano smart contract infrastructure without starting from scratch for Bitcoin. This means:
This work is part of a broader collaboration called BitVMX FORCE, launched by IO, Fairgate Labs, and Rootstock Labs. At Bitcoin 2025, IO demonstrated the UPLC-to-RISC-V compiler, leveraging the BitVMX verifier stack, paving the way for safe, scalable, and expressive smart contracts on Bitcoin.
IO believes Bitcoin can serve as the settlement layer for a new class of decentralized applications. By anchoring computation and interoperability on secure, auditable systems like BitVMX, the goal is not only to enable new functionality but also to bridge multiple ecosystems and communities.
The toolchain is planned to open soon. In the meantime, watch for announcements from IO and BitVMX FORCE and:
