Gas Abstraction

A smart contract that allows a third party (dApp, wallet, or enterprise) to pay transaction fees on behalf of users. This enables gasless transactions for end-users.

• How it works: The user signs a transaction, and a Paymaster contract validates and pays the gas in the native token.
• Use Case: Onboarding users who don't yet own ETH on Ethereum or MATIC on Polygon.

Allows users to pay transaction fees using any ERC-20 token in their wallet, not just the network's native gas token (e.g., ETH).

• Mechanism: The protocol automatically swaps a portion of the user's ERC-20 tokens for the native gas token via a decentralized exchange to cover the fee.
• Benefit: Simplifies the user experience by eliminating the need to manage multiple token balances for gas.

Enables users to pre-approve a set of transactions or a spending limit for gas fees over a specific time period, creating a seamless session-based experience.

• Function: A user signs a meta-transaction granting a session key limited permissions, allowing multiple actions without repeated fee approvals.
• Example: Playing a blockchain game where each in-game action doesn't require a separate wallet confirmation and gas payment.

Gas abstraction is a fundamental feature enabled by Account Abstraction (ERC-4337), which decouples transaction validation and fee payment logic from the core protocol.

• Smart Contract Wallets: User accounts become smart contracts that can contain custom logic for who pays fees and with what asset.
• Flexibility: Allows for complex sponsorship rules, batch transactions with a single fee, and subscription models.

Off-chain infrastructure that receives, forwards, and sometimes subsidizes user transactions, acting as an intermediary between the user and the blockchain.

• Process: The user signs a transaction and sends it to a relayer, which submits it to the network and pays the gas fee.
• Purpose: Reduces latency, can aggregate transactions for efficiency, and is a common architectural component for gasless services.

The business logic behind who ultimately bears the cost of transaction fees, shifting it away from the end-user.

• Models:
  • dApp Pays: The application subsidizes fees to acquire users.
  • Sponsor Pays: A project or advertiser covers fees for specific actions.
  • Fee Waivers: Conditional waivers based on user behavior or loyalty.
• Goal: To align transaction costs with value capture, not user friction.

A pattern where users sign messages off-chain, and a relayer submits the transaction and pays the gas fee on their behalf. Key components include:

• Signed UserOp: The user signs their intent without a gas fee.
• Relayer Network: A service that broadcasts the transaction, often using a gas tank.
• Signature Verification: A smart contract verifies the user's signature before execution. This is a foundational pattern for gasless onboarding and is formalized in systems like ERC-2771 for meta-transactions.

A user experience pattern that grants temporary, limited permissions to a dApp to perform actions on the user's behalf without requiring a signature for each transaction. This abstracts gas by:

• Batching operations: Multiple actions within a session (e.g., gaming moves, DeFi swaps) can be bundled into a single gas-paid transaction.
• Sponsored sessions: The dApp or a paymaster can cover the gas for the entire user session.
• Reduced friction: Eliminates the need for a wallet popup and gas approval for every interaction.

An implementation where users pay transaction fees using an ERC-20 token instead of the native chain token (e.g., ETH). This is facilitated by:

• Paymaster Contracts: As defined in ERC-4337, which swap the user's ERC-20 tokens for the native gas token.
• DEX Integration: The paymaster often uses an on-chain Automated Market Maker (AMM) like Uniswap to perform the token swap atomically within the transaction.
• Stablecoin Dominance: This is particularly popular for paying fees in stablecoins like USDC or USDT, providing price predictability.

Infrastructure that aggregates multiple user operations (UserOps) into a single on-chain transaction to amortize gas costs. Key aspects include:

• Economies of Scale: By batching operations, the fixed base gas cost is shared, reducing the effective fee per user.
• Bundler Network: A decentralized network of nodes that compete to bundle and submit UserOps, similar to validators in a blockchain.
• Fee Market: Bundlers can set their own fee policies and prioritize UserOps, creating a secondary gas market for abstracted transactions.

A business model where a third party (e.g., a dApp, protocol, or advertiser) fully covers the gas cost for a user's transaction to reduce friction. Common in:

• Onboarding Flows: Allowing new users to mint an NFT or perform their first swap without any crypto.
• Promotional Campaigns: Brands sponsoring gas for specific actions like voting or claiming rewards.
• Enterprise Use Cases: Companies covering gas for employee interactions with corporate wallets. This is often implemented via a whitelisted paymaster that only sponsors specific, approved transaction types.

A paymaster is a smart contract that sponsors transaction fees on behalf of users, creating a new trust vector. Key security considerations include:

• Contract Integrity: The paymaster logic must be secure against exploits that could drain its funding.
• Validation Rules: Paymasters can implement rules (e.g., whitelisted tokens, dApps) which must be correctly enforced to prevent subsidy abuse.
• Front-running Risks: Mempool visibility of sponsored transactions can lead to Denial-of-Service (DoS) attacks by spamming the paymaster.

Sustainable gas abstraction requires viable economic models for sponsors. Common approaches include:

• dApp-Sponsored: Applications pay fees to reduce user friction, costing a portion of their revenue.
• Token-Sponsored: Projects pay fees for transactions using their own ERC-20 token, creating a circular economy.
• Subscription/Flat Fee: Users pay a flat rate (e.g., monthly) for unlimited transactions, with the service provider managing gas cost volatility. Each model must account for gas price volatility and user acquisition cost to remain solvent.

Block builders and validators are ultimately paid in the chain's native token (e.g., ETH). Gas abstraction must ensure their incentives are preserved:

• Fee Payment Guarantee: Systems like EIP-4337's bundlers must convert sponsored fees to native ETH, ensuring validators are paid.
• Bundler Economics: Bundlers aggregate user operations; they face MEV risks and must manage transaction ordering to remain profitable after covering sponsored costs.
• Staking Requirements: In some designs, paymasters or bundlers may need to stake native tokens, aligning them with network security.

Simplifying gas for users can introduce centralization points:

• Relayer Dependence: Users may rely on a few dominant relayers or bundler services to submit transactions, creating a single point of failure.
• Censorship: A centralized paymaster could censor transactions based on user, dApp, or token type.
• Wallet Lock-in: Solutions are often tied to specific smart contract wallets, potentially reducing user sovereignty and portability. The trade-off between seamless UX and decentralized, permissionless access is a core design challenge.

Widespread gas abstraction can fundamentally alter a blockchain's fee market and token utility:

• Reduced Native Token Demand: If most fees are paid in stablecoins or altcoins, demand pressure on the native token (critical for security) may decrease.
• Fee Market Complexity: Multiple currencies and sponsorship logic can make gas price prediction and wallet estimation more complex.
• Monetary Policy: For chains where fee burning is part of monetary policy (e.g., EIP-1559), abstraction must ensure the value accrual mechanism to the native token remains intact.

A user experience where the end-user does not hold or spend the native blockchain token for fees. This is achieved through meta-transactions or paymaster sponsorship.

• Relayers: Off-chain services that receive signed messages, pay the gas, and broadcast the transaction.
• Gas Station Network (GSN): An early implementation of a decentralized relayer network for meta-transactions.
• Key Benefit: Drastically lowers onboarding friction for new users.

Temporary private keys granted to an application, allowing it to perform a limited set of actions on a user's behalf without requiring a signature for each transaction. This enables batch transactions with a single gas payment.

• Use Case: A gaming dApp can perform multiple in-game actions within a pre-defined session without interrupting the player.
• Granular Permissions: Keys can be restricted to specific contracts, functions, spending limits, and time windows.
• Revocable: Users can revoke session keys at any time.

A network participant in the ERC-4337 ecosystem that aggregates multiple UserOperations into a single on-chain transaction. The bundler is responsible for paying the gas fee upfront and is reimbursed by the EntryPoint contract.

• Role: Acts as a transaction miner for the account abstraction layer.
• Economics: Earns fees via priority fees (tips) included in UserOperations.
• Decentralization: A competitive market of bundlers is essential for network health and censorship resistance.

A transaction where the gas fee is paid by a party other than the transaction sender, typically a dApp developer or service provider. This is the most common form of gas abstraction.

• Business Model: Used for user acquisition, onboarding, or as a premium service feature.
• Implementation: Managed through a paymaster contract that validates the sponsorship logic.
• Examples: A decentralized exchange sponsoring a user's first swap, or a social media platform covering posting fees.