

S16 E37: Andrew Poelstra on Simplicity, Bitcoin Smart Contracts & Upgrades
Aug 6, 2025
01:38:53
Simplicity, a scripting language so simple that it can fit on a t-shirt, has finally launched on Liquid after a decade of development. Andrew Poelstra, who works as director of research at Blockstream, explains how it works & why it's good for Bitcoin.
Time stamps:
(00:00:50) Introducing Andrew Poelstra
(00:01:45) Simplicity: Now Live on Liquid
(00:02:12) Elements and Liquid’s Technical Evolution
(00:03:09) Is Simplicity a Response to Solidity?
(00:05:40) Simplicity’s Programming Model & Rust Inspiration
(00:08:04) Demo Applications and Simplicity Playground
(00:10:03) Why Not Stick with Bitcoin Script?
(00:11:48) Bitcoin Script’s Limitations and Quirks
(00:19:14) Simplicity’s Capabilities: Computation & Covenants
(00:22:26) Formal Verification and Multi-Language Implementations
(00:25:21) Machine-Checkable Proofs and Contract Safety
(00:29:07) Covenants, OP_CAT, and Script Extension Fears
(00:33:26) Simplicity as a Future Script Extension Path
(00:34:31) Ethereum’s Design Mistakes & Simplicity’s Approach
(00:53:00) Simplicity’s Lateness and Ethereum’s Rise
(01:01:12) Simplicity’s Usability and Adoption Challenges
(01:04:18) Potential Use Cases for Simplicity: Vaults, Business Logic, Quantum Signatures
(01:08:06) Wallets and Simplicity Integration
(01:16:30) Simplicity vs. Soft Forks for New Opcodes
(01:19:01) Jets: Optimizing Simplicity with Native Code
(01:22:44) Collider Script and High-Cost Emulation
(01:24:44) Resource Limits and Transaction Size
(01:29:34) Non-Scammy, Technologically Interesting Altcoins: Monero, Zcash, Grin, and Sia
(01:33:14) Where to Learn More About Simplicity