LI.FI public demoGas fronting custom

Custom destination gas amount demo

This page shows the full gas-fronting loop: fetch LI.FI's suggested fromAmount, override it with a custom fromAmountForGas, then request a quote so the response visibly proves what the API accepted.

Gas fronting docs

Customer path

Choose a tested preset or switch to custom to reproduce a specific customer route.

From addressUsed by /quote. Defaults to a valid placeholder so a reviewer can fetch quote data without connecting a wallet.To address

The default is a low-gas demo recipient so the official Widget can surface its auto-refuel / Get gas message without needing a connected destination wallet.

SlippageIntegrator

API recommendation

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Custom fromAmountForGas

0.03 USDC · 30000

Custom vs recommended

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Total source amount (USDC)This is the full /quote fromAmount before reserving destination gas.Destination gas paid from source USDCThis becomes /quote fromAmountForGas. Increase it if the default recommendation is too low for the UX you want.

Fetch a gas suggestion or request a quote.

Suggested native gas

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Suggestion limit

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Quote HTTP

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Quote tool

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To amount

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Min to amount

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Steps

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Transaction request

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Gas suggestion request / response

{
  "request": {
    "chainId": "10",
    "fromChain": "8453",
    "fromToken": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
  },
  "note": "Click Get API suggestion."
}

Quote request / response

{
  "request": {
    "fromChain": "8453",
    "toChain": "10",
    "fromToken": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "toToken": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
    "fromAmount": "10000000",
    "fromAmountForGas": "30000",
    "fromAddress": "0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266",
    "toAddress": "0x3333333333333333333333333333333333333333",
    "slippage": "0.005",
    "integrator": "lifi-public-demo"
  },
  "response": {
    "note": "Click Fetch quote with custom gas."
  }
}

Official LI.FI Widget · wide gas/refuel mode

Open network and tool selection in the production Widget UI

This is the Widget's wide variant in refuel mode. Use the route controls below to pass bridge/exchange allow or deny lists into the official Widget. An allow list deliberately forces the target tool, so a better competing route cannot hide the new-chain route being tested.

Path: Base USDC → Optimism USDC + Optimism ETH

Widget source amount: 10 USDC

API custom gas: 0.03 USDC

Route visibility controls

Tool options are loaded from LI.FI's live /v1/tools API. Select multiple bridges or exchanges, then Apply. Selecting a tool in Allow automatically removes it from Deny, and vice versa.

All tools available

Allow bridgesAny

Force one or more bridge/solver tools for new-chain testing.

Loading LI.FI tools…

Deny bridgesAny

Exclude bridge tools while leaving the remaining routes comparable.

Loading LI.FI tools…

Allow exchangesAny

Force one or more exchange tools when the route includes swaps.

Loading LI.FI tools…

Deny exchangesAny

Exclude exchange tools without forcing one exact exchange.

Loading LI.FI tools…

Loading official LI.FI Widget…

Boundary to show in the demo

/gas/suggestion returns a recommended source-token fromAmount plus the destination native-token amount and limit.
The user/custom UI can set a larger fromAmountForGas in /quote; the raw request panel proves the exact value sent.
This is destination gas fronting. It does not sponsor the source-chain transaction and should not be presented as Composer/contractCalls support.