Balancer DOCS

Native Asset as Address Zero

The Balancer protocol uses the address zero to represent the native asset address of the chain.

Joining with native asset

For example, to join the 50/50 WBTC/WETH pool with WBTC and ETH, the address zero needs to be used instead of the WETH address, like this:

//...
const AddressZero =  '0x0000000000000000000000000000000000000000';
// 50/50 WBTC/WETH Pool
let pool = await pools.find(
  '0xa6f548df93de924d73be7d25dc02554c6bd66db500020000000000000000000e'
);

const tokensIn = [
  '0x2260fac5e5542a773aa44fbcfedf7c193bc2c599', // WBTC
  AddressZero, // ETH
];
const amountsIn = ['10000000000', '1000000000000000000'];
const slippage = '1'; // 100 bps = 1%
const { to, data, minBPTOut } = sdk.pools.buildJoin({
  pool,
  userAddress: address,
  tokensIn,
  amountsIn,
  slippage,
});

Swap with native asset

The same applies to swaps:

//...
const AddressZero =  '0x0000000000000000000000000000000000000000';

const tokenIn = AddressZero; // eth
const tokenOut = '0x2260fac5e5542a773aa44fbcfedf7c193bc2c599'; // wBTC
const amount = String(BigInt(100e18)); // 100 eth

// Building the route payload
const payload = await sdk.swaps.buildRouteExactIn(
  sender, 
  recipient,
  tokenIn, // eth
  tokenOut, // wBTC
  amount,
);

But MATIC is not address zero

It's true, MATIC is the native asset of Polygon chain and has it's own address(0x0000000000000000000000000000000000001010). However, the Balancer protocol consider it like address zero for efficience purposes, avoiding the contracts to manage native assets for other addresses than address zero.

So, for example, to join the 50/50 WMATIC/BAL pool with BAL and MATIC, the address zero needs to be used, like this:

//...
const AddressZero =  '0x0000000000000000000000000000000000000000';
// 50/50 WMATIC/BAL Pool
let pool = await pools.find(
  '0x0280d9a1434c4a42014d35987243b9d893e00dcd000200000000000000000803'
);

const tokensIn = [
  '0x9a71012b13ca4d3d0cdc72a177df3ef03b0e76a3', // BAL
  AddressZero, // ETH
];
const amountsIn = ['10000000000', '1000000000000000000'];
const slippage = '1'; // 100 bps = 1%
const { to, data, minBPTOut } = sdk.pools.buildJoin({
  pool,
  userAddress: address,
  tokensIn,
  amountsIn,
  slippage,
});