Cross-rollup sessions are broken. A user swapping on Arbitrum cannot natively extend that session to a lending action on Base without signing new transactions and paying new gas fees on a new chain. This is the modular user experience bottleneck.
account-abstraction-fixing-crypto-ux
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Why Cross-Rollup Sessions Are Impossible Without AA
Externally Owned Accounts (EOAs) are the fundamental bottleneck for seamless cross-rollup UX. This analysis deconstructs why stateful, gasless sessions across chains like Arbitrum and Base require smart accounts and session keys, unlocking the next paradigm in modular blockchain interaction.
introduction
THE SESSION GAP
The Modular UX Bottleneck
Modular blockchains fragment user sessions, making seamless cross-rollup interactions impossible without account abstraction.
Smart contract wallets solve this. Account abstraction standards like ERC-4337 and StarkWare's native AA enable session keys. A user signs one intent, delegating temporary authority for a multi-step, cross-rollup operation to a session key managed by a bundler.
Without AA, you have intents without execution. Protocols like UniswapX and CowSwap popularized intent-based trading, but their solvers are limited to single-chain execution. Cross-rollup sessions require a generalized intent solver that can orchestrate actions across fragmented liquidity and state.
Evidence: The rise of intent-centric architectures from Anoma to SUAVE demonstrates the market need. However, their cross-domain execution layers remain theoretical without the universal account layer that AA provides for managing session state and gas.
key-trends
WHY AA IS NON-NEGOTIABLE
The Session Imperative: Three Trends Forcing the Issue
The promise of a unified cross-rollup user experience is collapsing under the weight of its own architectural contradictions.
01
The Problem: Fragmented Liquidity & State
A user's assets and positions are siloed across dozens of rollups and L2s. A simple cross-chain swap today requires signing multiple transactions, paying multiple fees, and waiting for multiple confirmations.
- User Experience: A single DeFi action can require 5+ wallet pop-ups and $50+ in gas across chains.
- Protocol Reality: UniswapX, CowSwap, and Across rely on intents precisely because direct atomic execution is impossible.
5+
Wallet Pop-ups
$50+
Gas Cost
02
The Problem: Non-Atomic Intent Settlement
Intent-based architectures (like UniswapX) delegate transaction construction to solvers, but settlement is still bound by the user's EOA. This creates a critical gap: the solver's cross-rollup actions cannot be atomically tied to the user's final approval.
- Security Risk: Users must sign a blanket approval, trusting the solver's entire execution path.
- Inefficiency: Solvers must over-collateralize or use slow, expensive bridges like LayerZero or Wormhole for safety, baking risk premiums into costs.
~500ms
Solver Latency
High
Risk Premium
03
The Solution: Account Abstraction as the Session Layer
Only AA provides a programmable account that can sponsor gas, batch operations, and—critically—enforce a single, cross-rollup session key. This session acts as a temporary, scoped authority for a solver, making complex intents atomic and trust-minimized.
- Atomic Guarantee: A user signs one session intent; the solver's actions across Optimism, Arbitrum, and Base either all succeed or all revert.
- Economic Shift: Gas sponsorship and batched settlement can reduce end-user costs by -70%, moving the burden to dApps and solvers.
1
User Signature
-70%
User Cost
deep-dive
THE CORE CONSTRAINT
Architectural Showdown: EOA vs. Smart Account
Externally Owned Accounts (EOAs) are a dead-end architecture that prevents the seamless, multi-step user experiences required for cross-rollup interoperability.
EOAs lack stateful logic. An EOA is a key pair, not a contract. It cannot hold persistent data or execute conditional logic across multiple transactions, which is the prerequisite for managing a cross-rollup session.
Smart Accounts are programmable endpoints. An ERC-4337 account or a Safe wallet is a smart contract. It maintains state, enabling it to coordinate multi-step flows, batch actions, and enforce rules—the exact capabilities needed for cross-rollup operations.
Session keys require contract state. A user-approved session for a dApp like UniswapX or Across must be stored and validated on-chain. Only a smart account's storage can persist this permission, allowing a relayer to execute transactions on the user's behalf across chains.
Evidence: The ERC-4337 bundler and Paymaster infrastructure is the execution layer for intent-based systems. Without a smart account as the transaction originator, this infrastructure has no programmable entity to interact with or subsidize.
WHY AA IS NON-NEGOTIABLE
The Cross-Rollup Session Feature Matrix
Comparing the fundamental capabilities required for seamless cross-rollup user sessions, highlighting why native EOAs fail and Account Abstraction enables them.
| Core Feature / Metric | Native EOA (Status Quo) | Smart Account w/ AA (Solution) | Implication / Why It Matters |
|---|---|---|---|
Atomic Multi-Rollup Batch | User action across Arbitrum & Optimism executes as one unit or fails entirely. | ||
Sponsored Gas (Gas Abstraction) | DApp or relayer (e.g., Biconomy, Stackup) pays fees, removing native token requirements. | ||
Session Key Validity Window | Per-transaction (1) | Configurable (e.g., 24 hours) | Enables 'logged-in' state for DeFi loops across chains without repeated signing. |
Cross-Chain Nonce Management | Chain-specific (Chaotic) | Global & Programmable | Prevents replay attacks & guarantees transaction ordering across all rollups. |
Post-Execution Logic (Hooks) | Automate follow-up actions (e.g., bridge yield to Base) after a main trade on Uniswap. | ||
Fee Payment Asset | Native Gas Token Only | Any ERC-20 (USDC, ETH) | Eliminates the need to pre-fund each rollup with its specific gas token. |
Recovery / Social Auth | Recover a compromised session via guardians (Safe{Wallet}) without losing the account's history. |
protocol-spotlight
THE AA-ENABLED PIPELINE
Builders on the Frontier: Who's Solving This Now
Cross-rollup sessions require a persistent, programmable agent. These projects are building the essential infrastructure.
01
The Problem: Stateless EOAs
Externally Owned Accounts (EOAs) cannot hold state or execute logic across chains. A session that starts on Arbitrum cannot natively continue its intent on Base without manual, signed transactions for each step, breaking UX.
- No Session Memory: Each action is a discrete, signed atomic unit.
- Fragmented Liquidity: User must manage gas and approvals on every chain.
- Impossible Abstraction: Cannot batch a multi-rollup swap or bridge action.
1
Chain per Tx
Manual
Every Step
02
The Solution: Account Abstraction Wallets
Smart contract wallets (ERC-4337) act as the persistent agent. They hold user intent and session state, delegating execution to off-chain bundlers and paymasters.
- Session Keys: Delegate limited authority for a sequence of actions across chains.
- Gas Abstraction: Paymaster sponsors gas in any token, on any chain.
- Atomic Multi-ChainOps: Bundle a cross-rollup swap (e.g., via UniswapX) into one user signature.
ERC-4337
Standard
Multi-Chain
Single Session
03
The Enabler: Intent-Based Infra
Protocols like UniswapX and CowSwap separate declaration (intent) from execution. AA wallets submit intents; a network of solvers competes to fulfill the cross-rollup path optimally.
- Solvers as Cross-Chain Agents: They navigate liquidity across Arbitrum, Optimism, Base to fulfill the user's end state.
- Infrastructure Integration: Bridges like Across and LayerZero become solver tools, not user-facing products.
- Result: User signs "get me X token on Chain Z"; the system handles the rest.
Solver Network
Execution Layer
Intent-Driven
Paradigm
04
The Orchestrator: Cross-Chain Messaging
AA wallets need a reliable command channel. Cross-chain messaging (CCM) protocols like LayerZero and Axelar deliver signed messages from the user's wallet on one chain to its instance (or a solver) on another.
- State Sync: Communicates session progress and authorization proofs.
- Not for Users: The AA wallet is the messaging client; the user never sees bridge UI.
- Critical Layer: Enables the AA wallet to be the single point of control across the modular stack.
Secure
Message Passing
Wallet-to-Wallet
Communication
counter-argument
THE FALLACY
The Steelman: "But We Have Relayers and Gas Sponsorship"
Existing gas abstraction solutions fail to enable seamless cross-rollup sessions due to fragmented trust and economic models.
Relayers are not wallets. A relayer like Biconomy or Gelato executes a transaction on behalf of a user but lacks persistent state. A cross-rollup session requires a single, verifiable identity and policy engine across multiple chains, which a stateless, per-transaction relayer cannot provide.
Gas sponsorship fragments trust. Protocols like Pimlico or Etherspot sponsor gas, but they delegate trust to each rollup's native paymaster. A user must trust a different entity on Arbitrum, Optimism, and zkSync, destroying the unified security model required for sessions.
ERC-4337 is chain-bound. Account Abstraction's entry point contract and paymaster are deployed per-chain. A session key signed on Base is meaningless on Polygon zkEVM without a costly and trust-heavy cross-chain message to sync state, which defeats the purpose.
Evidence: Try creating a single spending limit that works across Arbitrum and Optimism using only relayers. You will need two separate off-chain services, two on-chain approvals, and two fee logic sets—this is a patchwork, not a session.
takeaways
THE SESSION STATE PROBLEM
TL;DR for Architects
Cross-rollup user sessions require persistent, portable state that vanilla EOAs cannot provide.
01
The Problem: Stateless EOAs
Externally Owned Accounts have no native session state. Every transaction is atomic and isolated, forcing users to re-authenticate and re-approve for each cross-chain hop. This breaks UX for multi-step, multi-rollup flows.
- State is ephemeral: No persistent signer or logic between txs.
- No batched intent: Each signature is for a single, on-chain action.
- Gas sponsorship impossible: Can't delegate fee payment for a session.
1:1
Sig:Tx Ratio
0
Session Memory
02
The Solution: AA as a Session Layer
Account Abstraction (ERC-4337) creates a stateful smart account that can act as a session manager. The account's logic can hold temporary permissions, batch operations, and manage gas across chains.
- Persistent verifier: A session key or policy lives in the account.
- Intent batching: Sign once for a multi-step cross-rollup intent.
- Sponsored flows: Protocols like Biconomy or Stackup can pay gas for the session.
1:N
Sig:Tx Ratio
Portable
User State
03
The Bridge: Without a Portable Account, You Have None
Bridges like LayerZero, Axelar, and Across move assets, not account state. A cross-rollup session requires the user's authority to move with them. Only a smart account contract, deployable on any chain, provides this.
- Contract is the user: The smart account address is the unified identity.
- Interop is native: Session logic works on any EVM chain the account is on.
- Enables Intents: Frameworks like UniswapX and CowSwap require this for cross-chain orders.
Universal
Account Address
Required
For Intents
04
The Architecture: Session Keys & Gas Policies
Implementing sessions means defining on-chain rules in the smart account. This is the core architectural shift from transaction-based to session-based systems.
- Key Management: Temporary signing keys with limits (scope, spend, expiry).
- Gas Abstraction: Paymasters fund txs based on session allowances.
- Atomic Chaining: The account executes a pre-defined sequence across rollups in one signature.
Defined
On-Chain Rules
Abstracted
Gas Logic
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