Who pays gas fees in stablecoin payments? Per step and per chain

The account that signs a blockchain transaction is the one that pays its network fee, called gas on Ethereum-style chains. The fee is usually charged in that chain's own coin, not in the stablecoin. If your own wallet signs, you pay. If a provider signs on your behalf, the cost is settled between you and the provider. On Lumx's own legs (on-ramp, off-ramp and transfer), Lumx subsidizes the network fee, so a customer does not need ETH or TRX in a wallet.

The rule is short. What trips teams up is which steps their own wallet signs, which coin each chain wants, and how a fee they never see as a line item can still sit inside the price. This post stays on the network fee. The rest of the fee stack is in how stablecoin API pricing works.

What a network fee is, and why the stablecoin usually cannot pay it

A blockchain charges for every transaction it includes, to pay validators and to keep spam out. A stablecoin transfer is a call to a token contract, so it pays like any other transaction, in the chain's native coin: ETH on Ethereum and Base, POL on Polygon, TRX on Tron, XLM on Stellar. USDC and USDT are the cargo. The native coin is the fuel.

So a wallet can hold a large USDC balance and still be unable to send it, because it holds no fuel. Ethereum's documentation adds a detail that costs money in operations: the fee is paid whether a transaction succeeds or fails. A retry after a failure is a second fee.

Local rails have no equivalent. Pix (Brazil's instant payment system, run by the Central Bank) and SEPA transfers move between bank accounts with no per-transaction coin to hold. The fee exists only on the blockchain leg, so it matters most to teams that touch that leg themselves.

Who pays the network fee at each step of a Lumx payment?

Count the signatures. Lumx has three transaction types, and each status in its lifecycle either happens on a bank rail, inside a trade, or on the chain.

Which step touches the blockchain in each Lumx transaction type, and who signs it

Read down the last column. Inside Lumx, every wallet is custodial and every move is one API call, so the customer does not sign the blockchain step with a key of its own, and Lumx subsidizes the network fee on those legs. The only signature on the customer's side is the one that funds the wallet from outside, and that one pays its fee in the sender's own coin on whatever chain they use. How custody works is covered in custodial vs non-custodial wallets for businesses.

There is no gas field to fill. A transfer request carries currency, from, to, amount and an optional blockchain. The receipt on an off-ramp breaks the fees into a Lumx fee and a partner fee in the quote currency, plus the transactionHash and a block explorer link for the chain leg.

How the network fee works on Ethereum, Base, Polygon, Tron and Stellar

Each network has its own coin and pricing model. The table below uses only what the network's own documentation states, read on November 1, 2026. It gives protocol figures, not live prices, because fee markets move by the hour.

Fee coin, pricing model and documented figure for the five networks Lumx wallets support

Two things to take from the table. Stellar is a fixed sliver of XLM per operation, so it is predictable. Ethereum moves with demand, because the base fee is set by the blocks before it. Tron hides the cost in a resource model: a USDT transfer is a smart contract call that burns Energy, and an account with none staked or delegated has TRX burned instead. That mechanic, and why a wallet full of USDT can still fail, is in USDT on Tron for business payouts. The networks' own documentation publishes protocol mechanics, not dollar costs, so this post gives no USD figure per chain. For the same reason it does not rank the networks by price. Which chain suits which corridor is a separate decision, compared in Stellar, Ethereum, Polygon and Tron compared.

Lumx wallets exist on all five networks: Ethereum (USDC, USDT), Polygon (USDC, USDT), Base (USDC), Tron (USDT) and Stellar (USDC, BRL on-ramp only), per the wallets docs and the coverage page. A project-level default decides which network is used, and a request can name the blockchain to target another.

Can the stablecoin, or someone else, pay the network fee?

Usually not the stablecoin, and sometimes someone else. On Base, Stellar and Tron the docs describe a way for another party to pay, or for the fee to be paid in a token. Sponsorship moves the cost without removing it, because somebody still budgets for it.

• Base: the documentation points to paymaster services that let an app cover a user's fee.

• Stellar: a second account wraps the transaction in a fee-bump and pays the fee.

• Tron: an account with staked TRX can delegate Energy to another, so the sender burns no TRX.

• Provider-submitted transfers: the provider holds the funds and signs the transfer, so the customer's side carries no fuel balance for that step. With Lumx, the network fee on its own legs is subsidized by Lumx, so there is nothing for the customer to top up.

Paying in a token is a separate option: Base's documentation points to paying gas in a token instead of ETH. On Lumx, wallets are custodial, each move is one API call, and Lumx subsidizes the network fee on its legs, so there is nothing to sponsor on the customer's side.

The recipient pays no network fee

No, not when the recipient is paid in local currency over a bank rail. The blockchain leg ends before the recipient's bank account, so the only fee they can meet is their own bank's. Lumx does not deduct a fee from the amount that arrives on a Pix, SPEI (Mexico's interbank transfer system) or Bre-B (Colombia's instant payment system) payout. The payer sees the Lumx and partner fees in the quote.

Small payouts feel the network fee more

A network fee is a cost per transaction, not per dollar. Whatever a chain charges is charged once whether the payout is 20 or 20,000, so the fee's share of the payment shrinks in proportion. Take each 1 USD of network cost:

Share of the payout taken by every 1 USD of fixed per-transaction cost

A platform sending thousands of small payouts feels it. A treasury paying a few large invoices barely does. That is why a flat network allowance in a quote matters more at small tickets, and why a pass-through that varies per payout is harder to reconcile at month end.

On Lumx, the number to read is the one that settles. A locked-rate quote returns a baseTargetAmount and a finalTargetAmount. The 30-second lock carries no fee, and the 1-minute and 5-minute locks do. The transaction receipt then itemizes the Lumx fee and the partner fee against the amounts that moved.

Comparing network cost between providers

You rarely see the network fee as its own line, so compare what lands.

1. Fix the route: same corridor, same stablecoin, same network, same amount.

2. Count the steps your own wallet signs. Each one is a fee on top of the quote and a second balance to keep funded.

3. Ask how the cost is priced: flat per network, a minimum, or folded into the spread.

4. Ask for the amount the recipient receives at your median payout and at your smallest common one.

5. Ask who absorbs the fee when a transaction fails or is retried.

I would start any provider comparison by counting how many transactions the client's own wallet has to sign in the flow, before looking at a single percentage. Each signed step is a network fee carried outside the quote and a second balance that someone has to keep funded and alert on. The cleanest answer for a fintech that never wants its operations team watching an ETH or TRX balance is zero signed steps, and I would take a higher quoted fee to get it. When a fee leaves a recipient short, why a recipient got less traces it.

When network fees are the wrong thing to optimize

Chasing the cheapest chain is the wrong first move in three cases. When payouts are large, the fee is a rounding error next to the FX spread, so the better question is the final amount at your size. When the recipient is paid over a bank rail, the fee never reaches them, so it is a cost line for you and a reason to change nothing on their side. And when the destination fixes your corridor, the rail and the stablecoin the destination supports decide the route before fee levels do. The off-ramp explainer shows where the blockchain leg sits in a payout.

What this looks like on a Pix payout with Lumx

Lumx is stablecoin payments infrastructure for businesses that move money between Latin America and the rest of the world: one API to collect, hold, convert, and pay out in BRL, MXN, COP, USD, EUR, and GBP or in USDC and USDT, over local rails such as PIX, SPEI, PSE, Bre-B, ACH, FEDWIRE, SEPA, and Faster Payments, with SWIFT and on-behalf-of payments and collections (POBO and COBO) in USD, EUR, and GBP, plus named virtual accounts, custodial wallets, and KYB/KYC built in.

Take a platform that pays a supplier in Brazil. The platform is a Lumx customer, already through KYB (know your business, the verification of a company and its owners). Its custodial wallet holds USDC on one of the supported networks, funded either by an on-ramp from a local deposit or by a stablecoin transfer from a wallet the platform controls elsewhere. Only that second route puts the platform in the role of signer, and that is where a network fee in its own coin sits. The fee on Lumx's legs is subsidized by Lumx, so the platform keeps no ETH or TRX balance for them.

For each payment the platform requests a quote, passes it to the off-ramp call, and Lumx debits the wallet, converts the amount and pays the reais over Pix. The supplier sees the amount that arrives, and Lumx does not deduct a fee from it on a Pix, SPEI or Bre-B payout. Only the recipient's own bank can charge them. If the platform asks for more than the wallet holds, the call fails with an insufficient balance error before anything moves. On success the receipt carries the amounts, the rate, the fees and the transaction hash, so the finance team reconciles against the receipt and not against the request.

The global payments page shows the full set of rails, and the USDC to BRL page shows the corridor this example runs on.

Methodology and sources

Fee mechanics were read in each network's own documentation on November 1, 2026: Ethereum gas, Base network fees, POL and EIP-1559 transactions on Polygon, Tron's resource model, and Stellar fees. Figures describe a protocol minimum or a documentation example, not a live price, and the 600 free Bandwidth on Tron is a chain parameter that can change. Lumx behavior comes from the Lumx docs pages on coverage, wallets, transactions, exchange rates and errors, and from the transfer and transaction endpoints, read on the same date.

Verified on November 1, 2026. Operational context, not legal, tax, or investment advice.

Cover photo: Zulfugar Karimov on Unsplash.