Fee Sponsor on EVM

We're excited to announce that Dfns now supports gas fee sponsorship on Ethereum and other EVM-compatible chains. This feature allows you to pay gas fees on behalf of your users directly through your wallet infrastructure leveraging the latest protocol-level capability called EIP-7702, which is now live as part of Ethereum’s Pectra upgrade. It is supported by a lightweight, gas-optimized smart account architecture developed by Dfns. 

At Dfns, we’re focused on building tools that don’t just secure digital assets but also make them easier to use in real-world applications. Earlier this year, we introduced Fee Sponsors on Solana. Today, we’re expanding this feature to Ethereum and other major EVM chains, making it easier than ever to create frictionless, gasless experiences for your users.

Pectra, a new approach to onchain fee for EVMs

The Ethereum roadmap has long aimed to increase the programmability of accounts. With the activation of EIP-7702 as part of the Pectra upgrade, Ethereum has made significant progress. This upgrade introduces a new transaction type (0x04), which allows an Externally Owned Account (EOA)—the standard wallet controlled by a private key—to behave like a smart contract but only for the duration of a single transaction.

Here’s how it works:

1. The user’s EOA initiates and signs the transaction.
2. The transaction includes logic that delegates execution to a smart contract without converting the user’s wallet into a full smart contract wallet.
3. After the transaction is completed, the EOA behaves like a normal wallet again, but now also supports smart contract functionality through op code 0x04.

This innovative design unlocks a range of powerful use cases that require fast, automatic fee sponsorship to avoid bad user experiences or transaction workflow failures. By leveraging the right contract logic, a transaction initiated by an EOA can now include a mechanism that delegates the payment of gas fees to another wallet, all within a single seamless transaction flow without the need to convert the user wallet into a full smart contract account.

How fee sponsors work on Ethereum

We've built on top of this capability with a minimal, gas-efficient smart account architecture. This architecture enables fee sponsorship natively within our Wallets-as-a-Service platform, with full support for policies, audit trails, and permission models already trusted by institutional clients. 

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This smart contract is inspired from the SafeLite example, fully tested and audited by RAID Square, and is deployed on the following chains:

Here’s how the end-to-end flow works:

1. Set up a sponsor wallet: Choose an organization-controlled wallet on Dfns and fund it with ETH. This wallet will act as the sponsor and cover gas fees.
2. Collect user intent: A user initiates a transfer from their organization-controlled wallet. No ETH required on their end.
3. Pass feeSponsorId in the API request: Use the Dfns API to link the transfer to the sponsor wallet by including the feeSponsorId.
4. Dfns constructs an EIP-7702 transaction: Our infrastructure prepares the payload to delegate execution to the smart contract and attaches the sponsor’s signature.
5. Broadcast the transaction: The user wallet initiates the transfer, the sponsor wallet pays the gas, and everything is logged complete with audit trails, policy context, and cryptographic signatures.

Creating a sponsored transfer on Ethereum

Creating a sponsored transfer on Ethereum (or any supported EVM chain) is simple and uses the same familiar Dfns endpoint:

POST /wallets/:walletId/transfers
{
  "kind": "Native" | "ERC20" | "ERC721",
  "network": "Ethereum",
  "feeSponsorId": "fs-xxx",
  ...
}

The transaction only proceeds if both the sponsor and sender are properly authorized through policy checks. The entire process is governed by your organization’s existing permission and policy framework, so you don't need to manage relayers or deploy custom contract logic.

Fully audited 7702 smart contract

Security is core to everything we build at Dfns. Our smart account architecture for fee sponsorship is no exception. To ensure the robustness of our implementation, we commissioned a full independent audit from RAID Square, a cybersecurity firm specializing in blockchain infrastructure and smart contract risk mitigation, and founding member of the Ligue pour la Sécurité du Web3 (LSW3).

The audit covered our DfnsSmartAccount.sol contract and was completed in May 2025. RAID Square found no critical or high-severity vulnerabilities. The contract follows best practices in both logic and deployment, and we continue to apply rigorous internal and third-party testing processes. This gives developers and institutions confidence that our fee sponsors are built on secure, production-grade infrastructure, with full audit trails and cryptographic guarantees.

A gasless future, finally ready to scale

With Fee Sponsors now live on Ethereum and other EVM-compatible networks, it’s easier than ever to create smooth, gasless user experiences without compromising on control or reliability. Whether you're building a consumer app, managing treasury movements, or onboarding new users, Fee Sponsors let you:

• Remove the need for users to hold ETH or native gas tokens
• Automate transfers using your existing policies and permissions
• Streamline operations with secure, auditable transactions through one API call

You can use Fee Sponsors today on Ethereum, Base, BNB Chain, Optimism, and more: app.dfns.io/get-started

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