Bitcoin execution and trust models

Key Insights

• Bitcoin programmability has stagnated due to its limited scripting language and the absence of a trust-minimized BTC bridge.
• Rollups are the most Bitcoin-aligned architecture for programmability, but none are live yet due to technical challenges like proof verification.
• Despite interest, sidechains and externally sequenced layers rely on offchain trust assumptions, weakening Bitcoin’s native security guarantees.
• If usage patterns mirror Ethereum, rollups could support up to $66B in BTC collateral and $2T in annualized BTC-stablecoin swaps.

What is Bitcoin Programmability and the Current State

Bitcoin programmability refers to the ability to define rules around how Bitcoin can be used beyond simple payments. While Bitcoin does support a scripting language, it lacks many of the basic opcodes required to express complex logic. Developers cannot build loops, track application-specific variables, or carry data forward across transactions in a way that supports complex application logic. These constraints were introduced by design to keep the base layer simple and verifiable, but they also make it difficult to build applications or coordination mechanisms directly onchain.