At a glance
| Decision | Practical answer |
|---|---|
| Start here | Choose a supported sponsored flow when customers should not need a second gas asset. |
| Choose deliberately | Check first-time approval, wallet compatibility and recipient-account readiness before advertising it. |
| Main tradeoff | The customer avoiding native gas does not make execution cost disappear. |
A customer has enough USDC for lunch but no ETH or SOL. Whether they can pay depends on the payment flow. An ordinary wallet transfer and a sponsored checkout are different operations even when they move the same asset.
The useful merchant question is: can this supported customer complete this request without first acquiring a second token? That is narrower than claiming that the blockchain transaction has no cost.
Three different meanings of gasless
| Claim | What it can mean | What to verify |
|---|---|---|
| Customer does not need a native gas balance | Another party submits or funds the transaction | Wallet, asset, sponsor and required setup |
| Customer pays a fee in a stablecoin | Service funds native gas and charges the customer differently | Total amount and conversion/markup |
| Payment tool is currently free to use | Operator does not currently charge a particular usage fee | Scope, exclusions and future pricing |
These claims are not interchangeable. Solana's fee documentation still specifies native network fees, and Ethereum's gas documentation explains fees for EVM execution.
EVM: a signature can authorize a transfer
In an EIP-3009 flow, a compatible token supports a signed authorization that a relayer can submit. The customer authorizes the transfer details; the submitting party handles the onchain transaction. This can avoid a customer-funded gas transaction for that transfer.
The x402 EVM specification distinguishes this path from Permit2 and other supported methods. Do not infer the authorization method from the stablecoin's symbol. Check the exact contract, network and implementation.
A successful signing prompt is not itself a settled payment. Staff or fulfillment logic must wait for the applicable verified result. See payment processing.
Permit2: first approval is a separate question
A Permit2-based flow can support tokens without EIP-3009, but the wallet must establish the necessary allowance. The standard direct approval is an onchain transaction; supported permit or sponsored-approval paths can change the preparation required.
Therefore, distinguish a repeat payer with a suitable existing allowance from a first-time payer. Ask whether the checkout supports approval sponsorship or a compatible permit, and whether the payer's wallet can complete that method. Do not promise a first-time gasless experience based solely on a successful repeat payment.
The USDT/x402 guide explains why Polygon USDT0 requires different handling from a USDC EIP-3009 route.
Solana: the signer and fee payer can differ
Solana's x402 flow uses a transaction signed by the customer and a separate sponsor fee-payer signature. The SVM specification describes that separation. It does not require EIP-3009, which is an EVM token authorization standard.
A sponsor still needs to accept the transaction and fund its costs. Receiving-token-account readiness is another condition: not every deployed service creates a missing account or pays its rent. In the current PayIn flow, prepare the merchant's Solana USDC receiving account in advance. See Solana payment preparation.
A counter checklist before advertising the experience
- Identify the exact accepted asset and network.
- Confirm that the customer uses a supported signing wallet, not an unrelated exchange-withdrawal flow.
- Check whether a first approval or receiving-account setup is required.
- Confirm the configured sponsor and its supported route.
- Keep a clear recovery path if signing or settlement fails.
- Verify the completed receipt before handover.
Use a local configuration review or appropriate test environment for setup; do not ask staff to experiment with production revenue. A wallet's displayed estimate or a successful signature is not proof of merchant receipt.
What merchants should say
A precise statement is: “This supported checkout can sponsor the payment's network transaction; check the request and wallet prompts.” Avoid “USDC always needs no gas,” “x402 is free,” or “every customer can pay with only USDC.”
PayIn currently uses supported USDC routes, not arbitrary USDT or other-token payments. The full-cost worksheet separates sponsored execution from service, conversion and withdrawal charges. Return to the series overview for asset and provider decisions.