Composable: Exploring Crypto’s Building Blocks (an Espresso Pod)

In this episode of Composable, hosts Alysia and Ellie welcome Hasu, an expert in MEV and the strategy lead at Flashbots. They delve into the intricacies of MEV, which stands for Maximal Extractable Value, discussing what it is in detail, its evolution, and its implications for our multi-chain future. The conversation covers topics such as private RPCs, order flow auctions, and the impact of MEV on both user experience and protocol efficiency. The episode also explores the trade-offs between synchronous and asynchronous composability and predicts future trends in crosschain MEV and protocol design.
Relevant links from the show.
Flashbots writing
Flashbots forum
Archive of all MEV-related content

Composable is a bi-weekly podcast exploring crypto's building blocks. Hosted by Alysia and Ellie, and brought to you by Espresso.
Find us on X:
Composable — @composablepod
Alysia — @alysiatech
Ellie — @ellierdavidson

In this episode of Composable, Ellie and Alysia dive deep into one of blockchain's most critical yet confusing concepts: finality. Triggered by a real-world story of someone losing funds due to misunderstanding finality in crosschain transactions, they explore the nuanced definitions of finality, settlement, and confirmations across different blockchain layers.
The discussion reveals how finality is not a fixed concept but rather depends on trust assumptions, application requirements, and the observer's perspective. They examine how different stakeholders, from centralized exchanges to DeFi protocols, make trade-offs between speed and security when defining finality for their users.
Key topics covered: 
Defining blockchain finality
Finality vs settlement
Layer 2 finality considerations
Crosschain composability challenges
Real-world application examples
Developer trade-offs and decisions
Confirmations and block times
Variable finality factors
Composable is a bi-weekly podcast exploring crypto's building blocks. Hosted by Alysia and Ellie, and brought to you by Espresso.
Find us on X:
Composable — @composablepod
Alysia — @alysiatech
Ellie — @ellierdavidson

In this episode, hosts Alysia and Ellie tackle Ethereum FUD (fear, uncertainty, and doubt) head-on by rolling a special "Ethereum FUD" die—a special piece of swag that Espresso Systems produced for ETHDenver 2025—and discussing common criticisms of Ethereum. 
They cover everything from fee structures and L2 scaling solutions to fragmentation concerns and Ethereum's overall direction, diving into whether the FUD is valid or simply misconceptions and providing a balanced perspective on the challenges and design decisions facing Ethereum as it evolves.
Key topics covered:
Fees Too Low - Discussion of the criticism that low Ethereum fees indicate lack of usage and declining demand
Parasitic L2s - Debate over whether Layer 2 solutions help or harm Ethereum by potentially siphoning value from L1
Fragmentation - Analysis of liquidity and ecosystem fragmentation across multiple L2 chains
No North Star - Examination of claims that Ethereum lacks clear direction compared to competitors like Solana
Validator Economics - How fee levels impact validator profitability and network security
Product Market Fit - Challenges of finding sustainable use cases for blockchain technology
User Experience vs. Decentralization - Trade-offs between ease of use and maintaining decentralized principles

Composable is a bi-weekly podcast exploring crypto's building blocks. Hosted by Alysia and Ellie, and brought to you by Espresso.
Find us on X:
Composable — @composablepod
Alysia — @alysiatech
Ellie — @ellierdavidson

In this episode, Ellie and Alysia dive deep into intent-based bridges, specifically exploring Across Protocol and their proposed Across Prime upgrade. They examine how intent bridges work, their advantages over traditional bridges, and the capital efficiency improvements that Across Prime aims to deliver for solvers (i.e., the liquidity providers that fulfill user intents).

Key Topics Covered
What are intents and intent bridges - Definition and distinction from traditional bridges, focusing on how users can move assets cross-chain without worrying about underlying mechanisms
Intent bridge mechanics - How liquidity bridges work with solvers fronting funds on destination chains rather than actually moving tokens crosschain
Benefits for users - Native tokens (no wrapped assets), no slippage concerns, fast transactions, and simplified user experience compared to canonical bridges
Intent lifecycle walkthrough - Three-step process: initiate transaction, fill by solver, and settlement verification using UMA's optimistic oracle
Solver risks and challenges - Blockchain reorganization risks, sequencer confirmation dependencies, and capital lock-up issues during settlement periods
Across Prime proposal - New bonding mechanism that allows solvers to get paid immediately and reuse capital, dramatically improving capital efficiency
Capital efficiency explained - How solvers can potentially earn 50+ transaction fees per hour on the same liquidity instead of just one fee per settlement period
Technical implementation details - Merkle tree systems for tracking in-flight transactions and user-enforced verification mechanisms
Solver rebalancing challenges - Why relayers need better native bridging options to move funds between chains efficiently
ERC-7683 standard - Crosschain intent standardization for interoperability between different solver networks
NFT bridging limitations - Why liquidity bridges cannot support NFT transfers due to uniqueness constraints
Fair exchange problem - Distributed systems challenge of ensuring trustless exchanges and how Across addresses it theoretically and practically
Future outlook debate - Whether intents represent the future of crosschain interactions or merely a stopgap until better native interoperability emerges
Composable is a bi-weekly podcast exploring crypto's building blocks. Hosted by Alysia and Ellie, and brought to you by Espresso.
Find us on X:
Composable — @composablepod
Alysia — @alysiatech
Ellie — @ellierdavidson

In this episode of Composable, hosts Alysia and Ellie speak with Orest from t1 about proof aggregation, TEEs (Trusted Execution Environments), L2 security, and how these concepts relate to finality. The conversation explores Vitalik Buterin's recent post proposing a "two out of three" proof system combining TEE proofs, ZK proofs, and Optimistic proofs to enhance blockchain security while improving finality times. Orest also shares how t1 is implementing TEEs to achieve faster finality times for L2s while maintaining strong security guarantees.
Key Topics Covered:
Introduction to TEEs and how they work
Comparison between TEE proofs and ZK proofs
Vitalik's proposal for combining multiple proof systems
How t1 uses TEEs for integrity rather than confidentiality
Remote attestation process and its importance
Security considerations and risk models for TEEs
t1's unique approach combining TEE proofs with periodic ZK proofs
The challenges of vendor centralization in TEE ecosystems
Real-world tradeoffs between security, speed, and usability
Composable is a bi-weekly podcast exploring crypto's building blocks. Hosted by Alysia and Ellie, and brought to you by Espresso.
Find us on X:
Composable — @composablepod
Alysia — @alysiatech
Ellie — @ellierdavidson