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Gas station

Send a little native gas to up to 10 chains from one transaction, so a wallet can transact on chains it has never used. Off by default on each deployment.

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Arriving on a new chain with tokens but no gas is a dead end: the wallet can't even approve a swap. The gas station refuels up to 10 chains with their native gas token from one transaction on the chain the user already has funds on. It runs at app.layerhop.com/gas.

The gas station is off unless the deployment sets GAS_STATION_ENABLED=1; while it's off every /v1/gas/* route answers FORBIDDEN. The source is Gas.zip: one deposit, split evenly across the chains you pick, usually delivered within seconds. LayerHop takes no fee on refuels; Gas.zip's own fee is part of the quote.

Quote a refuel#

Terminal
curl -X POST https://api.layerhop.com/v1/gas/quote \
  -H "content-type: application/json" \
  -d '{"srcChain":"base","sender":"0xYourWallet","destinations":[{"chain":"arbitrum","usd":2},{"chain":"optimism","usd":2},{"chain":"bsc","usd":2}]}'

The quote (good for about 60 seconds) has:

  • tx: one transaction on srcChain, paid in its native token (value = depositWei). Send it from sender.
  • destinations: what each chain receives (expectedWei of its native token, its USD value, and the usual seconds).
  • fees: ourFeeBps: 0 and providerFeeUsd (the deposit minus what's delivered).
  • simulation: an eth_call of tx from sender. ok: false usually means the wallet doesn't hold enough for the deposit plus the network fee.

Before returning tx we decode it and check it is a deposit(chains, to) call on Gas.zip's deposit contract with exactly your destinations, your recipient and the quoted value. A mismatch is a PROVIDER_ERROR, never a transaction to sign. Gas.zip's own numbers are checked too: its price of the native token must be within 3% of LayerHop's price feed (the deposit is sized from it, and can't be worth more than the USD you asked for plus 3%), and each destination's Gas.zip chain id comes from a table LayerHop keeps, not from Gas.zip's live list (a chain whose id changed is not offered until we check it). Without a price of our own, or with prices apart, the quote is a PROVIDER_ERROR; try again shortly.

Rules#

  • 1 to 10 destinations, all different, none equal to srcChain.
  • One amount for all: Gas.zip splits a single deposit evenly, so every destination takes the same usd.
  • Between $0.50 and $50 per chain, within Gas.zip's own limits (GET /v1/gas/chains lists both, per chain).
  • Pay with the source chain's native token (srcToken may be omitted or name the native token).
  • recipient defaults to the sender.

Destinations Gas.zip can't serve right now (e.g. out of liquidity) make the quote fail with NO_ROUTE, naming them; drop them and quote again.

Watch it arrive#

  • GET /v1/gas/status/{txHash}: the deposit's outbound transfers per chain; status becomes filled once every one is confirmed.
  • GET /v1/gas/balances?address=…&chains=arbitrum,optimism: native balances, for comparing before and after. The app does both every few seconds after the user signs.

Any refuel can also be looked up with the transfer tracker.

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