Bundled transactions are the breakthrough. Account abstraction is mis-sold as wallet recovery. Its real value is enabling a single user signature to authorize a complex, multi-step on-chain operation, abstracting away gas and intermediate token approvals.
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Blog
Why Bundled Transactions Are the True UX Breakthrough of Account Abstraction
Everyone talks about smart accounts, but the real game-changer is the UserOperation bundle. This is the atomic unit of composability that finally makes crypto usable, enabling complex, multi-step interactions with a single signature.
introduction
THE UX SHIFT
Introduction
Bundled transactions, not wallet abstraction, are the primary user experience breakthrough enabled by ERC-4337 and smart accounts.
The comparison is stark. A standard DeFi interaction requires 3-4 separate wallet confirmations. A bundled transaction via ERC-4337 executes the entire flow in one click, with a Paymaster handling gas fees in any token.
This mirrors intent-based architectures. Protocols like UniswapX and CowSwap popularized the intent model off-chain. Bundling brings this atomic, declarative UX on-chain, collapsing the multi-transaction funnel into a single, guaranteed state change.
Evidence: The Biconomy and Stackup bundler networks process millions of these UserOperations, demonstrating demand for abstracting execution complexity, not just key management.
thesis-statement
THE UX BREAKTHROUGH
The Core Argument: Bundles, Not Boxes
Account abstraction's primary value is not smart contract wallets, but the atomic execution of bundled intents.
The abstraction is the bundle. ERC-4337's UserOperation object is a declarative intent, not a direct transaction. This shifts execution logic from the user's client to a network of bundlers, enabling complex, multi-step operations in a single atomic unit.
Bundles kill meta-transactions. Services like Biconomy pioneered gas sponsorship, but required centralized relayers. Decentralized bundler networks now provide this as a permissionless, competitive market, making sponsored transactions a primitive, not a product.
This enables intent-based design. Users express a goal (e.g., 'swap ETH for USDC on Uniswap and bridge to Base via Across'). A solver network (like those for CowSwap or UniswapX) finds the optimal path, and a bundler executes it atomically. The user sees one signature, one success/failure state.
Evidence: The success of ERC-4337's EntryPoint, which has processed over 10 million UserOperations, proves demand isn't for new wallet UIs but for composable execution. Protocols like Ether.fi and KelpDAO use bundles to batch staking and restaking actions, reducing user steps from ~5 to 1.
key-trends
FROM GAS TO UX
The Emerging Bundle Economy: Three Key Trends
Account Abstraction's real breakthrough isn't smart accounts—it's the ability for third parties to bundle, sponsor, and sequence transactions, creating a new market for user experience.
01
The Problem: Pay-to-Play UX
Requiring users to hold native tokens for gas is a $10B+ adoption tax. It's the primary friction point for onboarding, dApp composability, and cross-chain activity.
- Blocks Mass Adoption: New users must acquire ETH/AVAX/SOL before their first interaction.
- Breaks User Flows: Multi-step DeFi actions fail if the user's gas wallet is empty.
- Kills Cross-Chain UX: Managing gas on 5+ chains is a non-starter for normies.
$10B+
Adoption Tax
~40%
Drop-off Rate
02
The Solution: Sponsored Transaction Bundles
Let applications pay for user gas, abstracting cost entirely. This enables gasless onboarding and turns user acquisition cost into a measurable CAC for dApps.
- dApps Subsidize UX: Protocols like Pimlico and Biconomy offer paymasters to sponsor gas in any token.
- Session Keys Enable Subscriptions: Users approve a bundle of future actions (e.g., 10 game moves) with one signature.
- New Business Models: Freemium models, trial periods, and loyalty rewards become possible on-chain.
0 Gas
For User
10x
Onboarding Speed
03
The Market: Intent-Based Bundlers
The real power is outsourcing transaction construction. Users state a goal ("swap X for Y at best rate"), and competitive solvers like UniswapX and CowSwap execute via optimized bundles.
- Solver Competition: Dozens of MEV searchers and solvers compete to fulfill your intent, improving price and reliability.
- Cross-Chain Native: Protocols like Across and Socket bundle bridging and swap into one atomic action.
- Guaranteed Outcomes: Users get what they want or the transaction reverts, eliminating slippage anxiety and failed tx.
~20%
Better Execution
1-Click
Complex Actions
THE UX BREAKTHROUGH
Bundled vs. Sequential: A Cost & Risk Comparison
A first-principles analysis of transaction execution models, quantifying the user experience and security trade-offs enabled by Account Abstraction.
| Feature / Metric | Bundled (Atomic) Execution | Sequential (Legacy) Execution |
|---|---|---|
Transaction Atomicity Guarantee | ||
Gas Cost for Multi-Op Session | Single base fee + aggregated calldata | N * (base fee + calldata) |
User-Paid Failed Op Gas | Only for failed top-level tx | For every failed intermediate tx |
MEV Surface for Multi-Op | Sealed bundle (via SUAVE, Flashbots) | N exposed transactions |
Front-Running Risk Between Ops | None (atomic) | High (e.g., sandwich between approve & swap) |
Typical Confirmation Latency | < 12 seconds (1 block) | N * 12 seconds |
Required Pre-Approvals | 1 UserOp signature session | N EOA signatures |
Infrastructure Dependency | Bundler & Paymaster (e.g., Stackup, Biconomy) | RPC endpoint only |
deep-dive
THE UX BREAKTHROUGH
Deconstructing the UserOperation: How Bundles Enable New Primitives
Bundling transforms the transaction from a single action into a programmable workflow, unlocking new application logic.
Bundles are stateful workflows. A single UserOperation is a signed intent, but a bundle is a sequence of these intents executed atomically. This allows applications to compose multi-step actions like a token swap followed by a deposit into a yield vault, which is impossible with isolated EOA transactions.
The bundler is the new relayer. Unlike a simple transaction broadcaster, a bundler like Pimlico or Alchemy's Rundler acts as a generalized executor. It simulates the bundle, pays gas upfront, and submits the final bundle to a mempool, abstracting gas management and nonce logic from the user.
Paymasters enable sponsored sessions. By decoupling fee payment from the signer, a paymaster like Biconomy or Stackup can sponsor gas for a user's entire session of interactions. This creates a session key model where users sign multiple UserOperations but pay only once, or not at all.
Evidence: The ERC-4337 standard processes over 1.5 million UserOperations monthly. Protocols like UniswapX use this architecture for intent-based swaps, where a solver's bundle fulfills a user's order across multiple liquidity sources in one atomic transaction.
protocol-spotlight
THE EXECUTION LAYER
Who's Building the Bundle Infrastructure?
Account abstraction's promise is delivered by specialized bundlers and paymasters. These are the protocols and networks executing the vision.
01
The Problem: User Experience is Fragmented
Users face a maze of separate transactions, gas payments, and wallet pop-ups for simple actions. This kills mainstream adoption.
- Gas Abstraction: Users must hold native tokens for every chain.
- Session Keys: Every dApp interaction requires a new signature.
- Atomic Composability: Multi-step DeFi actions are risky and slow.
5-10
Clicks per Swap
~70%
Drop-off Rate
02
The Solution: ERC-4337 Bundlers
Specialized nodes that bundle multiple UserOperations from a mempool and execute them on-chain for a fee, abstracting gas and ordering.
- PBS Model: Enables a competitive market for execution (like block builders).
- Sponsorship Gateway: Enables paymasters to sponsor gas fees.
- Network Effects: Bundlers with the best execution win user traffic.
~500ms
Bundle Latency
Stackup, Alchemy, Pimlico
Key Players
03
The Solution: Paymaster as a Service
Entities that sponsor transaction fees, enabling gasless UX, fee payment in ERC-20s, and novel subscription models.
- Gas Abstraction: Pay in USDC, not ETH. Zero-balance accounts become possible.
- Sponsored Sessions: Apps can pay for user onboarding and key actions.
- Policy Engine: Enforce rules for who gets sponsored (e.g., KYC'd users).
-100%
User Gas Cost
Biconomy, Candide, Etherspot
Key Players
04
The Problem: MEV & Censorship Resistance
Centralized bundlers can censor transactions or extract maximal value, recreating the problems of today's block builders.
- Trust Assumption: Users must trust the bundler's execution.
- Value Leakage: MEV from bundled transactions accrues to the bundler, not the user.
- Centralization Risk: A few dominant bundlers could control AA UX.
$1B+
Annual MEV
High
Centralization Risk
05
The Solution: SUAVE & Shared Sequencing
A decentralized block builder and sequencer network, like Flashbots' SUAVE, applied to the bundler layer for credibly neutral execution.
- MEV Redistribution: Protocols can design auctions to return value to users.
- Censorship Resistance: Decentralized ordering prevents transaction filtering.
- Cross-Chain Intents: Can become the execution layer for intent-based systems like UniswapX and CowSwap.
Decentralized
Architecture Goal
Flashbots, Espresso
Key Players
06
The Solution: Intent-Based Architectures
The logical endpoint: users declare what they want, not how to do it. Bundlers become solvers competing to fulfill the intent optimally.
- UniswapX: Already uses fillers as intent solvers for cross-chain swaps.
- Optimized Execution: Solvers bundle across DEXs, bridges (LayerZero, Across), and chains to find best price.
- User Sovereignty: The user gets a guaranteed outcome, not a transaction receipt.
10-30%
Better Execution
Anoma, Essential
Research Frontier
counter-argument
THE REALITY OF BUNDLERS
The Centralization Counter-Argument (And Why It's Overblown)
The perceived centralization risk of bundled transactions is a temporary, solvable problem that ignores the fundamental UX breakthrough.
Bundlers are not validators. The core security of the underlying chain (e.g., Ethereum, Arbitrum) remains intact. Bundlers are transaction processors, not consensus participants. Their power is limited to censorship and ordering, which are economic problems with known solutions like permissionless relay networks and inclusion lists.
Centralization is a market failure. A competitive market for bundling services will emerge, driven by MEV extraction and fee revenue. The current dominance of a few providers like Stackup or Pimlico is a launch-phase artifact, not a design flaw. Compare it to the early dominance of Infura in RPC services.
The UX trade-off is asymmetric. The user sovereignty lost to a temporary bundler oligopoly is negligible compared to the sovereignty users surrender daily to centralized exchanges and custodial wallets. Bundled transactions via ERC-4337 reclaim sovereignty by enabling gasless onboarding and social recovery.
Evidence: The Ethereum Foundation's 4337 roadmap explicitly prioritizes decentralization of bundlers. Proposals like SUAVE aim to create a decentralized block builder market, a model directly applicable to bundler networks. The path to permissionless execution is clear.
FREQUENTLY ASKED QUESTIONS
Bundled Transactions FAQ
Common questions about why bundled transactions are the true UX breakthrough of account abstraction.
Bundled transactions are a core feature of account abstraction that allow multiple operations to be executed as a single, atomic unit. This means a user can approve a token and swap it on a DEX like Uniswap in one click, eliminating the multi-step, multi-confirmation process of traditional EOAs. It's the mechanism that enables gas sponsorship, session keys, and complex DeFi interactions without user friction.
takeaways
THE UX INFRASTRUCTURE SHIFT
TL;DR: Key Takeaways for Builders
Account abstraction's real value isn't just smart contract wallets; it's the ability to bundle and reorder transactions, unlocking new architectural primitives.
01
The Problem: User-Action Friction
Every user action requires a separate transaction, signature, and gas payment. This kills complex flows like swapping on Uniswap and bridging to L2 in one click.\n- Sequential steps create a 90%+ drop-off rate.\n- Users must hold the native token for gas on every chain.
90%+
Drop-off Rate
5+
Clicks per Flow
02
The Solution: Atomic Bundles (ERC-4337)
Bundle multiple operations into one user signature. A Paymaster pays gas, and a Bundler submits the bundle, enabling single-click, cross-app flows.\n- Sponsor gas via stablecoins or credit.\n- Atomic execution ensures all steps succeed or revert together, eliminating partial failures.
1-Click
Complex Flows
~500ms
Latency
03
The Primitive: Intents & Solvers
Move from explicit transactions to declarative intents (e.g., 'Get me the best price for 1 ETH on Arbitrum'). Solvers like UniswapX and CowSwap compete to fulfill them via bundled transactions.\n- Better execution through solver competition.\n- Abstracts complexity from the end-user entirely.
10-50 bps
Price Improvement
$10B+
Solver Volume
04
The Infrastructure: Bundler Profit Models
Bundlers (like Stackup, Alchemy, Pimlico) are the new MEV searchers. They profit by reordering and including transactions within a bundle.\n- In-bundle arbitrage captures value from user flow.\n- Priority fees can be shared with dApps or users, creating new incentive alignment.
~$100M
Annualized Revenue
-20%
Effective Gas Cost
05
The Risk: Centralization & Censorship
Bundlers and Paymasters become critical, centralized points of failure. A dominant bundler could censor transactions or extract maximal value.\n- Relayer risk mirrors early L1 validators.\n- Requires decentralized bundler networks and permissionless entry.
>60%
Top 3 Bundlers
Critical
Trust Assumption
06
The Blueprint: Build with Bundles First
Design your dApp as a series of intents, not transactions. Integrate a Paymaster for gas abstraction and partner with multiple bundlers.\n- Use Account Abstraction SDKs (ZeroDev, Biconomy, Rhinestone).\n- Treat gas as a backend cost, not a user problem.
10x
User Conversion
0
Native Gas Tokens
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