---
title: Gas drop
description: Delivering destination-chain native asset alongside the payout, so the recipient can transact on arrival.
---

import { MAX_GAS_DROP_ARBITRUM, MAX_GAS_DROP_SOLANA, MAX_GAS_DROP_SUI } from "/snippets/vars.mdx";

A user bridging USDC to a chain where they hold nothing cannot move it afterwards. Gas drop solves that: the fulfillment delivers a requested amount of the destination chain's native asset in the same transaction as the payout, out of vault float.

## Requesting it

`gas_drop` is a decimal string in base units of the destination chain's native asset: wei on EVM chains, lamports on Solana, MIST on Sui. Send an empty string or omit it for none.

```ts
const quote = quoteOf(
  await hular.getQuote({
    srcChain: "solana",
    dstChain: "arbitrum",
    srcToken: usdcOnSolana,
    dstToken: usdcOnArbitrum,
    tradeType: TradeType.EXACT_INPUT,
    amount: "25000000",
    recipient,
    refundAddress,
    gasDrop: "100000000000000",
  }),
);
```

It is priced into the quote like any other component: the cost appears in `fee_breakdown` as `gas_drop` on the destination side, and `amount_out` is already net of it.

## Ceilings

Each chain caps how much can be dropped. Exceeding the cap fails the quote with `gas drop exceeds the allowed maximum`.

| Destination | Maximum | Unit |
| --- | --- | --- |
| `arbitrum` | {MAX_GAS_DROP_ARBITRUM} | wei |
| `solana` | {MAX_GAS_DROP_SOLANA} | lamports |
| `sui` | {MAX_GAS_DROP_SUI} | MIST |

Read the live ceiling from `GetChains` rather than hardcoding it:

```ts
const { chains } = await hular.getChains({});
const dst = chains.find((c) => c.chain === "arbitrum");

dst.maxGasDrop;        // ceiling, base units
dst.nativeSymbol;      // "ETH"
dst.nativeDecimals;    // 18
```

`native_symbol` and `native_decimals` come back on the same message, which is everything needed to render a slider from zero to the cap without a second source of truth.

## Behavior

The drop is part of the fulfillment, not a separate transfer: the recipient receives tokens and native asset in one transaction, or neither. On a refund it is never delivered and never charged: refunds deduct only the committed refund fees, and `gas_drop` sits on the destination side.

When the destination token is itself the native asset, the request's `gas_drop` is ignored and priced as zero, because the payout already is gas. Same-chain swaps never carry a drop.

<Note>
  A recipient that is a contract must be able to receive native asset. If the transfer to it fails, the fulfillment fails with it.
</Note>