Summary: DeFi funnels leak value when users face multiple pop-ups (“approve,” then “swap,” then “bridge”) and transactions revert mid-flow. Batching with Account Abstraction—using ERC‑4337 smart accounts and EIP‑7702 native delegations—compresses those steps into one atomic action while enabling gas sponsorship and passkey logins, translating directly into higher conversion and lower CAC.

Account Abstraction for DeFi: Batching Transactions for Better UX

Target audience: DeFi product and protocol teams. Keywords: Gas optimization, Paymasters, Permit2, Signature aggregation, Session keys, EIP‑7702, ERC‑4337, EntryPoint v0.7.

— Pain

You ship a new swap or staking flow and watch 30–60% of users abandon at “Approve,” then another chunk drop when a second wallet prompt appears for the actual “Swap.” On L2s, calldata inflation and retry loops punish your margins; on L1, approvals plus swaps plus bridge hops balloon user clicks and MEV exposure. Your team trials ERC‑4337 but gets burned by bundler reverts, mis-specified verification gas, or a paymaster signature edge case. Meanwhile, product wants passkey onboarding, yet P‑256 verification and AA compatibility look like a moving target across chains.

— Agitation

• Every extra popup costs you conversion. ERC‑4337 alt‑mempool overhead and poorly tuned gas fields frequently cause avoidable reverts; v0.7 changed packing, gas fields, and penalties, and bundlers enforce ERC‑7562 validation rules—if your account or paymaster violates them, the whole bundle can revert. That’s missed deadlines and strained budgets. (github.com)
• Calldata costs went up with Pectra (EIP‑7623), making inefficient batching and verbose signatures more expensive precisely when you need to compress user flows. (blog.ethereum.org)
• Security regressions are real: naive 7702 delegations can be phished; ERC‑6492 signature handling and certain verifier patterns have seen production incidents. One malicious delegation target or an unchecked “universal” signature path can drain wallets or sponsor the wrong operations. (blog.ethereum.org)
• Passkeys aren’t theoretical anymore. Mainnet’s Fusaka upgrade shipped a native P‑256 precompile (EIP‑7951), removing the last excuse to delay passkey-based auth. If you wait, your competitors will claim that UX edge first. (blog.ethereum.org)

— Solution

What we implement at 7Block Labs is a pragmatic “7702-front, 4337-spine” batching stack—built for DeFi KPIs, not demos.

1. Architectural decision: 4337, 7702, or hybrid

• When you need gas sponsorship, programmable validation, and deposits/stakes: ERC‑4337 smart accounts with paymasters. Use EntryPoint v0.7 (PackedUserOperation), which separates account and paymaster verification gas and introduces a 10% penalty for inflated execution gas caps—this alone can save bundling capacity and reduce fee waste. EntryPoint v0.7 address (multi‑chain) is 0x0000000071727De22E5E9d8BAf0edAc6f37da032. (github.com)
• When you only need atomic multi‑call UX and the user can pay ETH: EIP‑7702 (live since May 7, 2025 with Pectra) lets an EOA authorize contract code for a single transaction in the canonical mempool—no bundler, no alt mempool. The authorization tuples include chain_id, address, nonce, y_parity, r, s, and write a delegation indicator so the EOA executes the target’s code. (blog.ethereum.org)
• Hybrid: 7702 for one‑click “approve+swap” in the main pool, 4337 for sponsored onboarding, session keys, and programmatic guardrails. This reduces address churn and removes cold‑start deployment gas while keeping paymasters and modular validation. (blog.ethereum.org)

1. Batching patterns that actually move KPIs

• Approve + Swap in one atomic call:
  • EIP‑7702: build a delegation to a “batch executor” contract that performs Permit2 signature checks and then calls your swap router. One transaction, one prompt, canonical mempool inclusion. (eips.ethereum.org)
  • ERC‑4337: use smart accounts supporting executeBatch (Safe MultiSend, modular accounts per ERC‑6900, or account SDKs). Your UserOperation’s callData encodes an array of calls; if any revert, the whole batch reverts—no partial state surprises. (help.safe.global)
• Stake/Unstake + Claim Rewards:
  • Bundle claim → approve (if needed) → stake/unstake to compress “gas spikes” into one slot and minimize MEV windows.
• Cross‑protocol routes:
  • On L2, minimize calldata via signature aggregation and succinct batch encodings; on L1, prefer 7702 if sponsorship isn’t required to avoid alt‑mempool overhead. (eips.ethereum.org)

1. Gas optimization levers for DeFi

• EntryPoint v0.7 packing and penalties: adopt PackedUserOperation, tune verificationGasLimit vs paymasterVerificationGasLimit, and avoid over‑provisioning execution gas to prevent the 10% penalty. (github.com)
• Signature aggregation (draft ERC‑7766): where your validation scheme supports it (e.g., BLS), aggregators let bundlers verify a group’s signatures once, shrinking bundle calldata and gas—especially valuable on L2s where DA dominates cost. (eips.ethereum.org)
• Passkeys with EIP‑7951: move WebAuthn P‑256 signature checks on‑chain at a native precompile, replacing heavy Solidity libraries and slashing auth costs. Standardize on P‑256 across L1/L2 for uniform UX. (blog.ethereum.org)
• Calldata minimization post‑Pectra: prefer compact encodings and shared approvals (Permit2), and avoid redundant parameters in batched calls—Pectra’s higher calldata cost makes waste directly expensive. (blog.ethereum.org)

1. Paymasters and sponsorship that don’t blow up

• Use Verifying Paymasters that sign the exact PackedUserOperation fields you enforce server‑side; audit for the known “packing” trap where an underspecified hash lets initCode or callData drift between sign and use. Keep your paymaster signature in paymasterAndData (v0.9 syntax) and ensure bundler simulation covers your rules. (alchemy.com)
• Stake and deposits: follow EntryPoint staking rules; track reputation per ERC‑7562 to avoid your paymaster being quarantined by bundlers. Make sure your simulation endpoints honor all 7562 constraints. (docs.erc4337.io)

1. Safer 7702 delegations

• Restrict delegation targets: hard‑code an allowlist of delegation contracts in the client and present human‑readable intents. Use chain‑bound and nonce‑bound authorizations (built into 7702) and publish a quick “revoke/replace” UX. (blog.ethereum.org)
• Phishing‑resistant prompts: detect 7702 authorizations that attempt blanket token approvals; for token flows, route through Permit2 with explicit spend caps and expirations. (support.uniswap.org)

1. Production‑grade accounts

• Modular accounts (ERC‑6900): use plugin‑based accounts with execute/executeBatch, session keys for limited scopes, and passkey owner modules for P‑256. This keeps validation logic composable and auditable across releases. (eips.ethereum.org)
• Safe MultiSend: for treasury and DAO flows, MultiSend remains a battle‑tested way to batch admin operations (owner changes, threshold updates, payouts) with clear review. (help.safe.global)

1. Tooling that shortens your critical path

• Foundry v1.0 supports authoring and testing EIP‑7702 delegations locally (signDelegation, attachDelegation) and P‑256 signing (signP256). This de‑risks integration before mainnet. (paradigm.xyz)
• Alchemy/infra SDKs expose batch calls for smart wallets and support multi‑version EntryPoint (v0.6/v0.7); plan deprecation of v0.6 by 2026. (alchemy.com)

Practical example: one-click “Approve + Swap + Bridge deposit”

Goal: compress three prompts into one action for first‑time users on an L2.

• If the user holds ETH and doesn’t need sponsorship:
  • Build a 7702 authorization pointing to your BatchExecutor configured with:
    • Step 1: Permit2 signature verify (no onchain approval tx)
    • Step 2: Router swap (e.g., Universal Router or your DEX)
    • Step 3: Bridge deposit call
  • Submit a single type‑4 7702 transaction. Canonical mempool inclusion; atomicity guarantees if any step reverts. (eips.ethereum.org)
• If onboarding is gasless or token‑denominated:
  • Use an ERC‑4337 account with executeBatch([...]) and a Verifying Paymaster that only sponsors when route slippage and fee caps pass server checks; log a “sponsored swap” event before handleOps() for GTM analytics. (alchemy.com)

Security and compliance checkpoints (DeFi reality)

• ERC‑6492 and counterfactual signatures: only accept wrappers from your own factory and validate factory calldata strictly; avoid “universal” validators that perform arbitrary calls during validation. (eips.ethereum.org)
• 7702 phishing playbook: add a client‑side detector for unknown delegation bytecode; offer a one‑click “revoke delegation” transaction if anything anomalous is seen. EF guidance emphasizes nonce‑bound and chain‑bound delegations—turn those on by default. (blog.ethereum.org)
• Post‑Fusaka key policy: migrate passkey flows to EIP‑7951 across L1/L2 as they adopt the patched interface; drop custom P‑256 libraries to reduce audit surface. (blog.ethereum.org)

How this ties to business outcomes (and procurement reality)

We scope batching and AA work the same way you scope a growth initiative:

• Measurable funnel wins:
  • Reduce signature prompts from 3→1 for first swap; target +15–30% uplift in first‑session swap conversion. Attribute uptake to “one‑click” variants via A/B flags.
  • Cut revert rate on sponsored flows by tuning v0.7 gas fields and ERC‑7562‑compliant validation; measure handleOps() failures per 1,000 UserOps pre/post. (github.com)
• Cost controls:
  • Track calldata bytes per user journey and aim for double‑digit reductions post‑Pectra by removing redundant params and enabling aggregation where feasible. (blog.ethereum.org)
  • Shift authentication to P‑256 precompile to shave signature verification gas; report per‑login gas deltas post‑Fusaka. (blog.ethereum.org)
• Social proof and ecosystem momentum:
  • ERC‑4337 adoption is well past “pilot”—100M+ annual UserOps by end‑2024 and broad paymaster sponsorship show real, scaled behavior. Your stack should leverage that mature infra (bundlers, analytics, monitoring) rather than reinvent it. (theblockbeats.info)

7Block Labs’ methodology (what we do in 6–10 weeks)

• Design review
  • Pick the right split of 7702 vs 4337; define delegation allowlists and paymaster policy. Map calldata budgets against Pectra’s costs.
• Reference implementation
  • Ship a BatchExecutor (7702) and an executeBatch smart account (4337) with tests on Foundry (7702 cheatcodes), plus a Verifying Paymaster hardened against packing tricks. (paradigm.xyz)
• Observability
  • Dashboards for funnel, UserOp success, paymaster spend/runway, and calldata bytes per journey.
• Security
  • Light review of 7702 delegation code, ERC‑6492 usage, and paymaster policy; if you need deeper coverage, our security audit services handle end‑to‑end review.
• Procurement‑grade artifacts
  • Acceptance tests tied to KPIs, runbooks for revocation and rollback, and a “revert taxonomy” your support team can use.

Where to start (actionable next steps)

• If your primary pain is double prompts on swaps:
  • Implement a 7702 BatchExecutor with Permit2 integration; deploy an allowlisted delegate; add human‑readable intent prompts; instrument “approve+swap” conversion. Then evaluate 4337 only where sponsorship is needed. (eips.ethereum.org)
• If your priority is gasless onboarding or recurring actions:
  • Stand up an ERC‑4337 account (executeBatch), EntryPoint v0.7, and a strict Verifying Paymaster. Add session keys (ERC‑6900 module) for limited scopes like “trade up to X/day on DEX Y.” (github.com)
• If you’re betting on passkeys:
  • Move to P‑256 on‑chain verification with EIP‑7951 and a WebAuthn owner module; re‑audit auth logic; sunset legacy libraries. (blog.ethereum.org)

How we plug in

• Build with us: Our DeFi development services and smart contract development teams ship production AA stacks (4337 + 7702) with CI, monitoring, and analytics.
• Harden with us: Our security audit services cover ERC‑7562 compliance, paymaster/policy logic, 7702 delegates, and ERC‑6492 flows.
• Integrate with your stack: Need routers, oracles, cross‑chain? Our blockchain integration and cross‑chain solutions teams wire it up.
• Full‑cycle builds: If you’re moving from MVP to scale, our web3 development services and blockchain development services take you the rest of the way.

Proof points you can cite internally

• Protocol reality: Pectra enabled 7702 on May 7, 2025, delivering native batching in the canonical mempool and raising calldata costs—driving the need for compact batching. (blog.ethereum.org)
• Infra maturity: EntryPoint v0.7 stabilized packing, addresses, and gas semantics; major infra supports it and is deprecating v0.6 by 2026. (github.com)
• Adoption: 4337 saw 100M+ UserOps in 2024 and widespread paymaster sponsorship; batching is no longer a science project. (theblockbeats.info)
• Passkeys: Fusaka added P‑256 on L1, aligning with WebAuthn/YubiKeys and eliminating bespoke crypto code paths. (blog.ethereum.org)

Implementation notes (engineer-to-engineer)

• ERC‑4337 v0.7 fields:
  • Distinguish verificationGasLimit (account) and paymasterVerificationGasLimit; set preVerificationGas accurately to avoid underpricing and bundler rejection. Use simulateValidation (off‑chain) and handle the 10% unused execution gas penalty in your estimator. (github.com)
• Bundlers and ERC‑7562:
  • Make your account validate deterministically; avoid reading shared mutable state in validation; ban unassigned opcodes; follow storage access rules to keep your UserOps from being censored at the mempool. (docs.erc4337.io)
• 7702 authorization building:
  • Use Foundry’s signDelegation/attachDelegation for local tests; chain‑bind and nonce‑bind authorizations; default to allowlisted delegate bytecode; give users a one‑click revoke path. (paradigm.xyz)
• Permit2:
  • Replace legacy approve flows with Permit2 signatures to avoid extra txs; strongly type expirations and spend caps; educate users on signature prompts. (blog.uniswap.org)
• ERC‑6492:
  • Accept only your factory’s wrapper and prohibit arbitrary “prepareTo” calls; otherwise, a crafty path can bypass signature checks in edge cases. (eips.ethereum.org)

If you need a partner to ship this without “crypto-bro” drama—and with measurable business results—we’ll bring senior Solidity/ZK engineers who have done it in production.

Book a DeFi Growth Sprint Call

Citations:

• ERC‑4337 core, bundlers, paymasters, and ERC‑7562 validation guidance. (docs.erc4337.io)
• EntryPoint v0.7 release notes and address. (github.com)
• Alchemy smart-wallet batching and EntryPoint support/deprecation timelines. (alchemy.com)
• Pectra mainnet announcement, EIP‑7702 overview, calldata cost (EIP‑7623) context. (blog.ethereum.org)
• EIP‑7702 spec and auth tuple details. (eips.ethereum.org)
• ERC‑6900 modular accounts and batch execution. (eips.ethereum.org)
• ERC‑4337 ecosystem growth (UserOps). (theblockbeats.info)
• Fusaka/EIP‑7951 P‑256 precompile for passkeys. (blog.ethereum.org)
• Signature aggregation (ERC‑7766) rationale. (eips.ethereum.org)
• Foundry v1.0 7702 tooling. (paradigm.xyz)
• Permit2 and Universal Router batching guidance. (blog.uniswap.org)

Internal 7Block Labs links:

• DeFi development services
• Smart contract development
• Security audit services
• Blockchain integration
• Cross-chain solutions
• Web3 development services
• Blockchain development services