ERC-4337 infrastructure is the set of offchain bundlers, paymaster APIs, and account SDKs that turn the account abstraction standard into a working developer stack. Eight providers cover the market in 2026: Alchemy, Pimlico, Biconomy, ZeroDev, Coinbase Developer Platform, Stackup, Candide, and Etherspot. Each pairs a bundler that submits UserOperations to the EntryPoint contract with a paymaster service that lets apps sponsor gas, plus a smart account contract and SDK that abstracts the standard from the application code.
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Selection comes down to four variables: chain coverage, account model (vanilla 4337 versus modular ERC-7579 versus a custom kernel), pricing model, and whether the same provider also ships a frontend SDK such as Pimlico's Permissionless.js or Alchemy's Account Kit. This article compares the eight providers on those variables and recommends a pick per use case (consumer app, DeFi app, web3 game, agentic system).
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Fig 1. Eight providers cover the ERC-4337 production market in 2026. Selection turns on chain coverage, account model, and pricing.
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ERC-4337 infrastructure is the set of services that implement the offchain components of the account abstraction standard: bundlers that aggregate UserOperations into bundle transactions, paymasters that sponsor or denominate gas fees, and SDKs that expose smart account creation to application code. The onchain EntryPoint contract is canonical and identical across providers; the differentiation is operational.
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The standard was finalized in EIP-4337 (March 2023) and added smart contract wallet behavior to EVM chains without changing the protocol itself. Bundlers run as offchain services that monitor a UserOperation mempool, validate operations against the EntryPoint, and submit them as standard transactions paid in ETH. Paymasters are smart contracts that prepay gas on behalf of users; the paymaster API exposes that contract through a hosted endpoint so apps can authorize sponsorship at request time.
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Eight providers run production-grade infrastructure as of Q1 2026: Alchemy, Pimlico, Biconomy, ZeroDev, Coinbase Developer Platform, Stackup, Candide, and Etherspot. Each pairs a bundler endpoint, a paymaster API, and a smart account SDK. The remainder of this article compares them.
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An ERC-4337 provider runs three coordinated services: a bundler that listens for UserOperations and submits them to EntryPoint, a paymaster contract plus signing service that authorizes gas sponsorship, and an SDK that wraps account creation and signing in application-friendly calls. The provider charges either per-UserOp, per-gas-sponsored, or via a flat developer plan.
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A typical request lifecycle: the application calls the SDK to construct a UserOperation, the SDK signs it with the user's smart account credentials (passkey, EOA, or session key), the SDK submits the UserOp to the provider's bundler RPC, the bundler validates the UserOp against the EntryPoint's validateUserOp simulation, then aggregates it with other pending UserOps into a bundle that goes onchain as a single transaction. If a paymaster is attached, the paymaster contract pays the gas fee in ETH and either absorbs the cost (app-sponsored) or charges the user in a token like USDC.
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Most providers run their bundlers as open-source Rust or TypeScript binaries. Alchemy ships Rundler as an Apache-licensed Rust bundler. Pimlico ships Alto, also open-source. Stackup's bundler is also published. Open-source bundlers matter because applications that need full self-custody of UserOps can self-host the binary against any RPC.
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The eight providers split into three groups: full-stack providers that ship bundler plus paymaster plus account SDK (Alchemy, Pimlico, Biconomy, ZeroDev, Coinbase), bundler-first providers that focus on UserOp infrastructure (Stackup, Candide), and modular-account specialists that build their differentiation on ERC-7579 module composability (Etherspot, plus Pimlico and ZeroDev which also support modules). Coverage and account model are the largest differentiators.
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Chain coverage numbers above are read off each provider's docs as of Q1 2026 and shift week to week; treat them as orders of magnitude. The choice between vanilla 4337 (Alchemy Light Account, simple SimpleAccount-style contracts) and modular ERC-7579 (Kernel, Safe, Nexus, Etherspot accounts) is the largest structural difference: modular accounts plug in validators, hooks, and executors at runtime, which lets one account contract evolve as standards like ERC-7715 ship.
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Alchemy, Pimlico, Biconomy, and ZeroDev each ship a bundler, a paymaster API, and a smart account SDK as a coordinated product. They differ on account model (Alchemy's ERC-6900 Modular Account, Pimlico's account-agnostic SDK, Biconomy's Smart Account v2 with Nexus roadmap, ZeroDev's Kernel), chain coverage, and pricing transparency. The choice between them is usually decided by which trade-off matters most.
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Alchemy ships the Rundler bundler (open-source Rust, Apache 2.0), the Gas Manager paymaster API, and the Account Kit SDK with a Modular Account and a stripped-down Light Account. Account Kit covers React, React Native, and server-side TypeScript. The stack runs against Alchemy's own RPC infrastructure on roughly 25 EVM chains. The Modular Account follows Alchemy's ERC-6900 plugin standard rather than ERC-7579, so modules built for Kernel or Nexus do not drop in. Gas Manager exposes policy controls (per-user spend caps, allowlists, sponsored function whitelists) through a dashboard. Pricing is bundled with Alchemy's compute-unit billing, with sponsored gas billed at cost plus a markup. Alchemy's pitch is integration: an app already using Alchemy RPC flips on smart wallets without a second vendor relationship.
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Pimlico is the bundler-and-paymaster specialist of the group. Its Alto bundler is open-source TypeScript and runs on roughly 40 EVM chains, the widest coverage in the market. The Permissionless.js SDK is account-agnostic: it wraps any ERC-7579 modular account (Kernel from ZeroDev, Safe7579, Biconomy Nexus, Etherspot's account) behind a single TypeScript API. Pimlico raised a $4.2M seed round in November 2023 led by 1confirmation per Sequoia coverage and integrated with Safe to power Safe's smart account expansion. Pimlico ships two paymaster types: a verifying paymaster (offchain signed sponsorship) and an ERC-20 paymaster (user pays gas in USDC, USDT, or other tokens). Permissionless.js is the cleanest "vendor-neutral" choice for teams that want to keep account-contract optionality.
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Biconomy has shipped a smart account product since 2021, predating ERC-4337's finalization. The current generation is Smart Account v2, a modular account compatible with ERC-7579, paired with a bundler and dual paymaster (sponsorship and ERC-20). Coverage is roughly 25 EVM chains. The next-generation account, Nexus, is Biconomy's ERC-7579-native module-first design per the Biconomy docs. Biconomy's differentiator is cross-chain UX: the SDK exposes batched cross-chain transactions through Biconomy's MEE (Modular Execution Environment) layer. The Session Key Manager module is one of the more battle-tested implementations of session-scoped permissions, predating the ERC-7715 draft.
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ZeroDev built the Kernel account, the reference ERC-7579 modular account that most other providers (Pimlico, Stackup) also support. Kernel separates an account into a sudo validator, optional regular validators, executors, and hooks; modules plug into those slots at install time. ZeroDev's bundler runs as Ultra Relay, an optimized RIP-7560-style fast path that batches sub-second UserOp inclusion on supported chains. Coverage is roughly 30 EVM chains. Gas Policies exposes per-user gas budgets, function whitelists, and time-window sponsorship through a dashboard and API. Session keys are a native primitive in Kernel rather than a module, which simplifies the integration story for gaming and agentic use cases that need many short-lived signing keys.
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Four additional providers fill specific niches. Coinbase Developer Platform is the consumer-distribution path with sponsored gas on Base. Stackup is the neutral bundler vendor. Candide is Safe-aligned. Etherspot focuses on cross-chain orchestration with ERC-7579 forward compatibility. Each fits a use case that the full-stack four do not address as cleanly.
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Coinbase Developer Platform ships an opinionated, consumer-focused stack built around Coinbase Smart Wallet, a passkey-based smart account launched in June 2024 with no seed phrase. The CDP Bundler and Paymaster API run as a managed service on Base, Ethereum mainnet, and roughly 10 other EVM chains. On Base, the paymaster sponsors gas for free up to a per-app daily cap, which makes Coinbase the lowest-friction starting point for consumer apps targeting Base users. The Smart Wallet account is a custom ERC-4337 contract designed around passkey signing and Coinbase's account recovery flows, not a Kernel or Nexus account. Spend Permissions is Coinbase's session-key analog, scoped to specific functions and amounts.
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Stackup ships an open-source Go bundler and a paymaster service that supports both Kernel and Safe accounts. Coverage is roughly 20 EVM chains. Stackup's positioning is "bring-your-own-account," which appeals to teams that want a neutral bundler vendor decoupled from any particular account contract. Candide is the Safe-aligned provider: it ships the Voltaire bundler in Python, a sponsorship paymaster, and a Module Registry of audited Safe modules across roughly 15 EVM chains. Etherspot ships the Skandha bundler in TypeScript, the ArkaPaymaster, and its own modular account family with ERC-7579 forward compatibility across roughly 20 EVM chains, focused on cross-chain orchestration through batched UserOps.
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Fig 2. Capability matrix across the eight providers. No single provider leads on every dimension; selection is use-case driven.
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The right ERC-4337 provider depends on the application's primary constraint: distribution, modularity, cost, or chain reach. Consumer apps targeting Base lean toward Coinbase Developer Platform for the sponsored-gas onramp. Multi-chain DeFi apps lean toward Pimlico for chain coverage and account neutrality. Web3 games lean toward ZeroDev or Biconomy for session-key ergonomics. Agentic systems lean toward ZeroDev Kernel for ERC-7715-aligned permissions.
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Consumer apps (passkey onboarding, Base distribution): Coinbase Developer Platform. The Smart Wallet account is the only path to onboarding existing Coinbase users with one click, and the free paymaster on Base removes the gas-funding step entirely up to the per-app cap.
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Multi-chain DeFi apps (Ethereum L2 sprawl): Pimlico with Permissionless.js. The widest chain coverage (~40 chains) and account-neutrality let a DeFi app ship on Arbitrum, Optimism, Base, Linea, Scroll, and emerging chains without rewriting the client per chain.
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Web3 games (high-frequency UserOps, session keys): ZeroDev for native session-key ergonomics, or Biconomy for the Session Key Manager module if multi-chain composition matters more than per-key performance. Both pair well with paymaster sponsorship since game UserOps are usually fully sponsored.
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Agentic systems (autonomous agents signing scoped permissions): ZeroDev Kernel paired with ERC-7715-compatible modules. The validator/executor split in Kernel maps directly onto agent permission scoping: a regular validator handles the agent's signing key, an executor enforces spend caps, a hook enforces time windows. ERC-7715 session-key infrastructure is the natural pairing.
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Safe-aligned multisig or treasury apps: Candide's Voltaire bundler plus a Safe7579 account. The Module Registry's curation reduces audit surface, and Safe's institutional adoption makes this the path of least resistance for treasury tooling.
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The four practical trade-offs across providers are account-model lock-in, chain coverage, paymaster pricing transparency, and bundler self-hosting. Alchemy and Coinbase trade flexibility for polish; Pimlico and Stackup trade integration for neutrality; ZeroDev and Biconomy trade vendor neutrality for sharper product-specific features.
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Account-model lock-in is the largest hidden cost. An app that ships on Alchemy's Modular Account inherits ERC-6900 plugins, not ERC-7579 modules. Migrating to a Kernel account later requires recreating wallet addresses (since the account contract changes the salt input to create2) and asking users to migrate funds. Building on Permissionless.js or Stackup, which support multiple account contracts behind one SDK, defers this decision.
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Paymaster pricing is the second hidden cost. Sponsored gas is billed at the underlying ETH cost plus a provider markup, typically 5 to 25 percent. Coinbase's free Base paymaster removes this cost for capped consumer use cases but does not extend to other chains. Apps with paymaster spend in the high four figures monthly should benchmark the actual markup against self-hosting an open-source paymaster.
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Bundler self-hosting matters for two scenarios: regulated environments where UserOp custody must stay in-house, and high-volume apps where bundler bills exceed the cost of running Rundler or Alto on an RPC the team already pays for. All eight providers' bundlers (or compatible ones from this list) are open source. Self-hosting trades a developer-hour cost for predictable infrastructure economics.
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Eco Routes is a cross-chain stablecoin routing API. When a smart account on Base needs to spend USDC funded on Arbitrum, Eco quotes a route, locks intent, and executes the transfer behind a single UserOperation. Any ERC-4337 provider in this comparison can submit the UserOp; Eco handles the cross-chain liquidity and settlement underneath. The pairing is most natural when the smart account itself is multi-chain (Kernel and Nexus both support cross-chain validators), since Eco's intent-execution model collapses what would otherwise be a multi-step UX into one signature.
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For teams building consumer or DeFi apps that touch multiple chains, the practical pattern is: pick the provider that matches the use-case constraint (Coinbase for Base consumer, Pimlico for chain breadth, ZeroDev for agent permissions), and add Eco Routes when cross-chain stablecoin movement needs to feel like one transaction.
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Sources and methodology. Provider features verified against each vendor's public docs as of Q1 2026 (alchemy.com, pimlico.io, biconomy.io, zerodev.app, coinbase.com/developer-platform, stackup.sh, candide.dev, etherspot.io). EntryPoint contract behavior per EIP-4337. Chain coverage counts are read off vendor docs and shift week to week; treat as orders of magnitude. Fundraise references via Crunchbase and Sequoia press; quoted figures are not refreshed weekly.
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Account abstraction stack 2026
​What is a bundler?
​What is a paymaster?
​What is ERC-4337?
​ERC-7702 deep dive
​ERC-7715 session keys
​Smart wallet vs EOA
​Gas sponsorship explained
​Coinbase Smart Wallet deep dive
​Safe wallet deep dive
​Best smart wallets 2026
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Eco Routes is a cross-chain stablecoin routing API that fits behind any ERC-4337 provider's bundler. Teams shipping smart accounts that touch more than one chain can add Eco Routes to collapse multi-chain stablecoin transfers into a single UserOperation. See the Eco documentation for integration details.
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