How to Send Gasless Transactions? Complete Guide
Gasless transactions let users interact with dApps without holding native gas tokens by having a relayer or sponsor pay fees on their behalf; they’re implemented via meta‑transactions, trusted forwarders, or account abstraction.
Overview of Gasless Transaction
Gasless transactions (also called meta‑transactions) let a user sign an off‑chain intent which a relayer submits on‑chain while paying gas; the smart contract verifies the original signer and executes the action. This removes the onboarding friction of requiring users to buy native tokens before using a dApp.
Key components
- User: signs a structured message describing the desired contract call.
- Relayer / Sponsor: wraps the signed intent into a transaction, pays gas, and broadcasts it.
- Smart Contract Forwarder: verifies the signature and executes the requested function, ensuring the relayer cannot alter intent.
Standards and technologies
- EIP‑712 typed structured data signing is the cryptographic foundation for readable, secure off‑chain signatures.
- EIP‑2771 Trusted Forwarder standardizes how contracts accept meta‑transactions and recover the original signer.
- ERC‑4337 Account Abstraction enables smart‑contract wallets with programmable gas sponsorship and more decentralized bundler/relayer models.
Benefits
- Improved UX: users can interact immediately without buying gas tokens.
- Lower onboarding friction for mainstream users and mobile-first experiences.
Risks and tradeoffs
- Relayer trust and economics: relayers must be compensated (directly by dApp, via sponsorship, or via off‑chain settlement), and their incentives must be managed.
- Security: replay attacks, signature malleability, and improper forwarder verification are common pitfalls; implement nonce schemes and strict signature checks.
How to Send Gasless Transactions
Step 1 Prepare the intent
- Build the typed data payload (EIP‑712) describing the contract call and a nonce.
- Ask the user to sign the typed data with their wallet (wallet shows readable fields).
Step 2 Relay the signed intent
- Send the signed payload to a relayer endpoint (your backend or a relayer service).
- The relayer wraps the payload into a transaction calling the contract’s trusted forwarder or the contract directly (depending on implementation) and pays gas.
Step 3 On‑chain verification and execution
- The forwarder contract verifies the signature, nonce, and expiry, then calls the target contract as the original user.
- The target contract executes the requested function and emits events for tracking.
Practical tips
- Use audited forwarder libraries and follow EIP‑2771 or ERC‑4337 reference implementations.
- Implement replay protection with nonces and expirations.
- Monitor relayer economics and consider gas sponsorship caps to limit exposure.
Gasless transactions use EIP‑712 typed data so a user signs an off‑chain intent and a relayer submits it on‑chain; below are ready‑to‑use EIP‑712 payload examples (domain, types, message) and a short client snippet showing how to sign them.
EIP‑712 Payloads Essentials (quick)
Domain binds the signature to a dApp, chain, and contract; Types define the structured data schema; Message is the actual payload the user signs. Use nonces and expirations for replay protection.
Reas Also-
{
"domain": {
"name": "MyDApp",
"version": "1",
"chainId": 137,
"verifyingContract": "0xAaBbCc...1234"
},
"types": {
"EIP712Domain": [
{"name":"name","type":"string"},
{"name":"version","type":"string"},
{"name":"chainId","type":"uint256"},
{"name":"verifyingContract","type":"address"}
],
"Action": [
{"name":"user","type":"address"},
{"name":"action","type":"string"},
{"name":"value","type":"uint256"},
{"name":"nonce","type":"uint256"},
{"name":"deadline","type":"uint256"}
]
},
"primaryType": "Action",
"message": {
"user": "0xUserAddress...",
"action": "transferCredits",
"value": 100,
"nonce": 42,
"deadline": 1710000000
}
}