How Gasless Transactions Work in DeFi

Gasless transactions in DeFi work by separating the user who signs a transaction from the account that pays for its on-chain execution. Through meta-transactions, gas relayers, or account abstraction (ERC-4337), a third party — typically a platform like Definitive — pays the gas fee on behalf of the trader. The user's action executes onchain without requiring any native chain tokens in their wallet.

The Technical Mechanics of Gasless Transactions

To understand how gasless transactions are possible, start with how standard transactions work on EVM chains.

Standard EVM transaction model

An EVM transaction has a sender (msg.sender) who:

1. Signs the transaction with their private key
2. Pays gas from their own account in the chain's native token (ETH on Ethereum, MATIC on Polygon)
3. Initiates the state change on-chain

The gas payment and the transaction sender are coupled by default. The network won't process a transaction unless the sender's account has sufficient ETH to cover the maximum gas cost. This is a fundamental constraint of the base protocol.

Decoupling the signer from the gas payer

Gasless transactions work by creating a layer of indirection between the user who authorizes an action and the account that pays for it. The user still cryptographically signs their intent — this ensures the action is authorized by the legitimate account owner. But the gas payment comes from a different account.

This decoupling can be implemented in several ways:

Approach 1: Off-chain signed messages + on-chain relayer execution

The user signs a structured message (not a standard Ethereum transaction) expressing their intent — "swap 1000 USDC for ETH using Definitive." This signed message is not a transaction and costs nothing to create.

The signed message is submitted to a relayer service. The relayer validates the signature, verifies the user has the necessary token approvals, and constructs a real Ethereum transaction that calls a smart contract function with the user's signed message as a parameter.

The smart contract verifies the user's signature, confirms the intent is valid and authorized, and executes the action. The relayer's account pays gas. The state change occurs as if the user had initiated it directly.

Approach 2: ERC-2771 (Trusted Forwarder)

ERC-2771 formalizes the meta-transaction pattern. A "trusted forwarder" contract is designated, and the target contracts recognize this forwarder as authorized to relay transactions on behalf of users. The actual user's address is embedded in the call data (appended to msg.data), so contracts can still identify the original user despite the forwarder being the technical sender.

This is simpler than fully custom meta-transaction implementations and has been widely adopted in DeFi protocols. The limitation: contracts must explicitly support ERC-2771 by recognizing the trusted forwarder pattern.

Approach 3: ERC-4337 (Account Abstraction)

ERC-4337 introduces a fundamentally different transaction model that doesn't require changes to the EVM itself. Rather than a special transaction type, it works through:

• User operations (UserOps): Instead of regular transactions, users create and sign UserOps — structured objects describing the intended action
• Bundlers: Similar to relayers, bundlers collect UserOps, package them into real transactions, and submit them to the network
• EntryPoint contract: A singleton contract that processes bundled UserOps and coordinates execution
• Paymasters: Smart contracts that can pay gas for UserOps, enabling gasless experiences. A paymaster can be sponsored by a platform (Definitive covers your gas), or can accept gas payment in ERC-20 tokens instead of ETH

ERC-4337 enables more sophisticated gasless experiences than meta-transactions: multi-call operations in a single UserOp, flexible signature schemes (biometrics, multi-factor), and programmable gas payment logic. It's the most powerful and flexible approach for truly gasless user experiences.

Meta-Transactions and Account Abstraction

Meta-transactions and ERC-4337 account abstraction are distinct solutions to the same problem — gasless execution — with different trade-offs.

Meta-transactions

Meta-transactions are the older approach, predating ERC-4337. They rely on off-chain signed messages, relayer infrastructure, and smart contracts that understand how to verify and execute meta-transaction calls.

Advantages:

• No EVM changes required — works with existing Ethereum infrastructure
• Can be applied to existing smart contracts through minimal integration work (ERC-2771 trusted forwarder pattern)
• Well-understood and battle-tested since 2019
• Works today on all EVM chains

Limitations:

• Signature verification adds overhead to each contract call
• The "original sender" address handling requires care — some contracts don't correctly implement ERC-2771, leading to address extraction bugs
• Replay protection (preventing the same signed message from being executed twice) requires careful nonce management
• The relayer is a trusted party and single point of failure

ERC-4337 Account Abstraction

ERC-4337 launched on Ethereum mainnet in 2023 and has seen significant adoption on L2s. It standardizes the UserOp/Bundler/Paymaster model and creates a robust, protocol-level framework for programmable transaction execution.

Advantages:

• Standardized paymaster model makes gas sponsorship straightforward and auditable
• Smart contract wallets become first-class citizens — Safe, Squads, and other multisig wallets can fully participate
• Enables complex logic: batched operations, session keys, conditional execution
• Gas paid in ERC-20 tokens or sponsored externally through paymasters
• Less reliance on trusted forwarder patterns; more robust address handling

Limitations:

• Higher overhead per UserOp compared to regular transactions (EntryPoint contract interactions)
• Requires ERC-4337-aware bundler infrastructure, which is still developing in some environments
• Not yet available on all chains — deployment varies by network

What Definitive uses

Definitive's gas sponsorship draws on the most appropriate mechanism per chain. On EVM chains with mature ERC-4337 infrastructure, paymaster-based account abstraction provides the most robust gasless experience. On chains where meta-transaction patterns are more established, ERC-2771-based relaying provides equivalent user experience with proven infrastructure. For Solana, Definitive handles the fee abstraction through its own infrastructure given Solana's non-EVM fee model.

The implementation detail is largely invisible to traders — the experience is consistent: sign a trade, it executes, no gas cost.

Who Pays the Gas

Gas sponsorship raises the immediate question: if the user doesn't pay, who does? Understanding the economics of gas sponsorship clarifies whether it's sustainable and where the costs sit.

The gas payer in meta-transactions

In a relayer-based system, the relayer's wallet pays gas for every transaction it processes. The relayer needs to maintain funded accounts on every chain it supports, manage gas price estimation to avoid overpaying or failing, and have infrastructure to top up these accounts as they're depleted.

For Definitive, this means maintaining funded infrastructure wallets across Base, Arbitrum, Ethereum, Optimism, Polygon, Avalanche, BNB, HyperEVM, and Solana. As users trade, gas is consumed from these wallets. Definitive absorbs this cost as part of providing the service.

The gas payer in ERC-4337

In ERC-4337, the Paymaster contract pays gas. The Paymaster itself needs to be funded with ETH (or the chain's native token), and whoever funds the Paymaster is ultimately paying for gas. For sponsored gas models, the platform deposits ETH into the Paymaster contract. For pay-in-token models, the user's ERC-20 payment is converted to ETH by the Paymaster.

Definitive's paymaster is funded by Definitive — the company absorbs the cost of keeping the paymaster contract funded with sufficient ETH across chains.

The economic model

Gas sponsorship is not free charity. The costs are real and need to be offset by revenue. Definitive's model:

• Free-tier trading (majors and stablecoins on major chains): Trading fee is zero. Gas is sponsored. These trades don't directly generate fee revenue for Definitive. The rationale: high-volume institutional trading on these pairs benefits from zero friction; Definitive earns indirectly through volume-based tier progression and ecosystem growth.
• Fee-bearing trading (other assets): 85 bps at T5 down to 25 bps at T1 based on 30-day volume and EDGE staking. On these trades, trading fees offset gas costs and provide margin. On Arbitrum at $0.05–$0.10 gas per transaction, even a $100 swap at 85 bps ($0.85 fee) covers gas costs with margin remaining.
• EDGE staking: The staking model provides revenue and alignment incentives that support the platform's economic sustainability.

The economics work because gas costs on L2 chains are low, and trading fees on mid-tier and long-tail assets are meaningful. Ethereum mainnet gas is the most expensive; for mainnet transactions, fee revenue from larger trades (the typical mainnet trade size) covers sponsorship costs.

Limitations and Trade-offs

Gasless transactions solve a real problem but come with trade-offs that sophisticated traders should understand.

Relayer trust dependency

Meta-transaction relayers are trusted parties in the execution flow. If the relayer is compromised, it could potentially:

• Delay or drop transactions
• Execute transactions in a different order than intended
• Censor specific addresses

Well-designed relayer architectures include replay protection, signature verification by the destination contract, and fallback mechanisms. But the trust assumption is real. For meta-transaction-based gasless systems, the relayer's reliability and security is a dependency.

Replay attack risk

A signed meta-transaction message, if not properly protected with nonces, could theoretically be replayed — submitted multiple times. Robust implementations include nonce management (ensuring each signed message can only be executed once) and chain ID binding (ensuring a message signed for Arbitrum can't be executed on Ethereum). Definitive's implementation includes these protections, but traders should understand this is a non-trivial engineering consideration in any gasless system.

Smart contract risk for ERC-4337

The EntryPoint contract in ERC-4337 is a high-value target — it handles execution and gas payment for potentially millions of UserOps. The contract has been audited and is widely deployed, but as a complex smart contract handling significant value flows, it carries inherent smart contract risk. Higher-level components (Paymasters, Bundlers) add additional contract surface area.

Gas price estimation complexity

When users pay their own gas, they directly observe and choose gas price settings. In sponsored systems, the relayer or bundler estimates appropriate gas prices and overpays if necessary to ensure inclusion. During gas price spikes, the relayer may choose conservative settings that result in delayed transaction inclusion. The user loses direct control over this parameter — they're trusting the platform's gas management to be competent.

Chain availability

Gasless transaction infrastructure is not uniformly available across all chains and environments. Some chains have limited ERC-4337 adoption, limited relayer infrastructure, or unique fee models that require chain-specific solutions. Definitive has built out sponsorship infrastructure for its specific chain roster, but extending to new chains requires new integration work.

The UX cost of the relayer layer

Sponsored transactions add an infrastructure layer between the user's signing action and on-chain execution. In normal operation this is invisible, but under high network load or relayer stress, the relayer layer can add latency or fail entirely. Trading platforms need robust relayer infrastructure — including fallback mechanisms — to make gasless execution reliably work in production conditions.

For traders who want full control over gas settings and don't want dependency on a third-party relayer, standard direct transaction submission is always available. Gasless is a convenience feature that's appropriate for most active trading scenarios; the trade-off is the additional infrastructure dependency.

For the practical implications and user-facing comparison of gasless vs. gas-paying trading, see What is Gasless Crypto Trading. For the full feature set of Definitive's trading infrastructure, the onchain trading terminal overview provides context.

Frequently Asked Questions

What is the difference between meta-transactions and ERC-4337?

Meta-transactions are an off-chain signing pattern where a user signs an intent and a relayer submits it on-chain — an older approach that works with existing infrastructure. ERC-4337 (account abstraction) is a newer standard that introduces UserOps, Bundlers, and Paymasters as protocol-level constructs, enabling more sophisticated gas payment models including paying in ERC-20 tokens. Both can produce gasless user experiences; ERC-4337 is more powerful and standardized but requires more ecosystem support.

Do gasless transactions work with hardware wallets and custody providers?

Yes. Gasless transaction systems based on signed messages work with any signing device — Ledger, Trezor, Fireblocks, Fordefi, Safe, Squads. The user signs the intent with their hardware wallet or through their custody provider's approval workflow; the relayer handles on-chain submission. For ERC-4337, smart contract wallets like Safe are first-class participants. Definitive supports Fireblocks, Fordefi, Safe, and Squads natively.

Can gasless transactions be front-run or MEV-targeted?

The underlying trade execution in a gasless transaction is subject to the same MEV considerations as a standard transaction — it's the trade routing that determines MEV exposure, not whether gas is sponsored. Definitive's MEV protection (private market makers, smart order splitting, private relay infrastructure) applies to gasless transactions the same as any other. See the MEV protected trading guide for details.

What happens if the gas relayer goes offline during a trade?

If the relayer is unavailable when a trade is submitted, the transaction cannot be submitted to the blockchain until the relayer is back online. Well-designed systems include redundant relayer infrastructure and fallback mechanisms to minimize this risk. For time-sensitive operations (stop loss execution during a market move), relayer reliability is a critical requirement. Definitive's infrastructure is designed for production trading with high-availability standards.

Is gasless trading only available on Ethereum?

No. Gasless transaction infrastructure exists on all EVM-compatible chains and beyond. Definitive provides gasless trading on Base, Arbitrum, Ethereum, Optimism, Polygon, Avalanche, BNB, HyperEVM, and Solana. Each chain has its own gas fee structure, and sponsorship covers the fees specific to each chain's native model.

Ready to trade onchain with institutional-grade execution? Try Definitive — gasless, multichain, and built for serious traders.