# SDK API Reference

# AddLiquidity

This class provides functionality to:

• Perform on-chain queries to see the result of an addLiquidity operation
• Build an addLiquidity transaction, with slippage, for a consumer to submit
• Supported add types: SingleToken, Unbalanced, Proportional
• Supports Balancer v2 and v3

# Example

See the addLiquidity guide and the addLiquidity exampleopen in new window.

# Constructor

const addLiquidity = new AddLiquidity();

# Methods

# query

Simulate addLiquidity operation by using an onchain call.

query(
  input: AddLiquidityInput,
  poolState: PoolState
): Promise<AddLiquidityQueryOutput>

Parameters

Returns

Promise<AddLiquidityQueryOutput>;

AddLiquidityQueryOutputopen in new window - Data that can be passed to buildCall. Includes updated bptOut amount.

# buildCall

Builds the addLiquidity transaction using user defined slippage.

buildCall(input: AddLiquidityBuildCallInput): AddLiquidityBuildCallOutput

Parameters

Returns

AddLiquidityBuildCallOutput;

AddLiquidityBuildCallOutputopen in new window - Encoded call data for addLiquidity that user can submit.

# buildCallWithPermit2

Builds the addLiquidity transaction using user defined slippage and Permit2 signature for token approval.

buildCallWithPermit2(input: AddLiquidityBuildCallInput, permit2: Permit2): AddLiquidityBuildCallOutput

Parameters

Returns

AddLiquidityBuildCallOutput;

AddLiquidityBuildCallOutputopen in new window - Encoded call data for addLiquidity that user can submit.

# RemoveLiquidity

This class provides functionality to:

• Perform on-chain queries to see the result of an removeLiquidity operation
• Build a removeLiquidity transaction, with slippage, for a consumer to submit
• Supported remove types: Unbalanced, SingleTokenExactOutInput, SingleTokenExactInInput, Proportional
• Supports Balancer v2 and v3

# Example

See the removeLiquidity guide and the removeLiquidity example.

# Constructor

const removeLiquidity = new RemoveLiquidity();

# Methods

# query

Simulate removeLiquidity operation by using an onchain call.

query(
  input: RemoveLiquidityInput,
  poolState: PoolState,
): Promise<RemoveLiquidityQueryOutput>

Parameters

Returns

Promise<RemoveLiquidityQueryOutput>;

RemoveLiquidityQueryOutputopen in new window - Data that can be passed to buildCall. Includes updated amountsOut amount.

# queryRemoveLiquidityRecovery

Calculates proportional exit using pool state. Note - this does not do an onchain query.

queryRemoveLiquidityRecovery(
  input: RemoveLiquidityRecoveryInput,
  poolState: PoolState,
): Promise<RemoveLiquidityQueryOutput>

Parameters

Returns

Promise<RemoveLiquidityQueryOutput>;

RemoveLiquidityQueryOutputopen in new window - Data that can be passed to buildCall. Includes updated amountsOut amount.

# buildCall

Builds the removeLiquidity transaction using user defined slippage.

buildCall(
  input: RemoveLiquidityBuildCallInput,
): RemoveLiquidityBuildCallOutput

Parameters

Returns

RemoveLiquidityBuildCallOutput;

RemoveLiquidityBuildCallOutputopen in new window - Encoded call data for addLiquidity that user can submit.

# buildCallWithPermit

Builds the removeLiquidity transaction using user defined slippage and Permit signature for token approval.

buildCallWithPermit(
  input: RemoveLiquidityBuildCallInput,
  permit: Permit,
): RemoveLiquidityBuildCallOutput

Parameters

Returns

RemoveLiquidityBuildCallOutput;

RemoveLiquidityBuildCallOutputopen in new window - Encoded call data for addLiquidity that user can submit.

# Swap

This class provides functionality to:

• Perform on-chain queries to see the result of a Swap operation
• Build a Swap transaction, with slippage, for a consumer to submit
• Supports Balancer v2 and v3

# Example

See the swap guide swap exampleopen in new window.

# Constructor

const swap = new Swap(swapInput: SwapInput);

Note: SwapInput data is normally returned from an API SOR query but may be constructed manually.

# Methods

# query

Gets up to date swap result by querying onchain.

query(
  rpcUrl?: string,
  block?: bigint,
): Promise<ExactInQueryOutput | ExactOutQueryOutput>

Parameters

Returns

Promise<ExactInQueryOutput | ExactOutQueryOutput>;

ExactInQueryOutputopen in new windowExactOutQueryOutputopen in new window

The updated return for the given swap, either expectedAmountOut or expectedAmountIn depending on swap kind.

# buildCall

Builds the swap transaction using user defined slippage.

buildCall(
  input: SwapBuildCallInput,
): SwapBuildOutputExactIn | SwapBuildOutputExactOut

Parameters

Returns

SwapBuildOutputExactIn | SwapBuildOutputExactOut;

SwapBuildOutputExactInopen in new window | SwapBuildOutputExactOutopen in new window - Encoded call data for swap that user can submit. Includes minAmountOut or maxAmountIn depending on swap kind.

# buildCallWithPermit2

Builds the swap transaction using user defined slippage and Permit2 signature for token approval.

buildCallWithPermit2(
  input: SwapBuildCallInput,
  permit2: Permit2,
): SwapBuildOutputExactIn | SwapBuildOutputExactOut

Parameters

Returns

SwapBuildOutputExactIn | SwapBuildOutputExactOut;

SwapBuildOutputExactInopen in new window | SwapBuildOutputExactOutopen in new window - Encoded call data for swap that user can submit. Includes minAmountOut or maxAmountIn depending on swap kind.

# quote

Gives the combined return amount for all paths. Note - this always uses the original path amounts provided in constructor and does not get updated.

public get quote(): TokenAmount

Returns

TokenAmount;

TokenAmountopen in new window - Gives the combined return amount for all paths (output amount for givenIn, input amount for givenOut).

# inputAmount

public get inputAmount(): TokenAmount

Returns

TokenAmount;

TokenAmountopen in new window - Gives the combined input amount for all paths.

# outputAmount

public get outputAmount(): TokenAmount

Returns

TokenAmount;

TokenAmountopen in new window - Gives the combined output amount for all paths.

# queryCallData

public queryCallData(): string

Returns

string;

Encoded query data for swap that a user can call to get an updated amount.

# PriceImpact

This class provides helper functions to calculate Price Impact for add/remove/swap actions.

• Supports Balancer v2 and v3

# Example

See the price impact exampleopen in new window.

# Methods

# addLiquiditySingleToken

Calculate price impact on add liquidity single token operations.

addLiquiditySingleToken(
  input: AddLiquiditySingleTokenInput,
  poolState: PoolState,
): Promise<PriceImpactAmount>

Parameters

Returns

Promise<PriceImpactAmount>;

PriceImpactAmountopen in new window - Price impact for operation.

# addLiquidityUnbalanced

Calculate price impact on add liquidity unbalanced operations.

addLiquidityUnbalanced = async (
    input: AddLiquidityUnbalancedInput,
    poolState: PoolState,
): Promise<PriceImpactAmount>

Parameters

Returns

Promise<PriceImpactAmount>;

PriceImpactAmountopen in new window - Price impact for operation.

# addLiquidityNested

Calculate price impact on add liquidity nested token operations.

addLiquidityNested = async (
  input: AddLiquidityNestedInput,
  nestedPoolState: NestedPoolState,
): Promise<PriceImpactAmount>

Parameters

Returns

Promise<PriceImpactAmount>;

PriceImpactAmountopen in new window - Price impact for operation.

# removeLiquidity

Calculate price impact on remove liquidity operations.

removeLiquidity = async (
  input:
      | RemoveLiquiditySingleTokenExactInInput
      | RemoveLiquidityUnbalancedInput,
  poolState: PoolState,
): Promise<PriceImpactAmount>

Parameters

Returns

Promise<PriceImpactAmount>;

PriceImpactAmountopen in new window - Price impact for operation.

# removeLiquidityNested

Calculate price impact on remove liquidity single token nested operations.

removeLiquidityNested = async (
  input: RemoveLiquidityNestedSingleTokenInput,
  nestedPoolState: NestedPoolState,
): Promise<PriceImpactAmount>

Parameters

Returns

Promise<PriceImpactAmount>;

PriceImpactAmountopen in new window - Price impact for operation.

# swap

Calculate price impact on swap operations.

swap = async (
  swapInput: SwapInput,
  rpcUrl?: string,
  block?: bigint,
): Promise<PriceImpactAmount>

Parameters

Note: SwapInput data is normally returned from an API SOR query but may be constructed manually.

Returns

Promise<PriceImpactAmount>;

PriceImpactAmountopen in new window - Price impact for operation.

# BalancerApi

This class provides helper functions for interacting with the Balancer API.

# Example

See the examples for add/remove/swap linked above as these use BalancerApi to fetch required data.

# Constructor

const balancerApi = new BalancerApi(balancerApiUrl: string, chainId: ChainId);

# Methods

# pools.fetchPoolState

Finds state of given pool.

pools.fetchPoolState(id: string): Promise<PoolState>

Parameters

Returns

Promise<PoolState>;

PoolStateopen in new window - State of given pool.

# pools.fetchPoolStateWithBalances

Finds state of given pool including token balances and pool shares.

fetchPoolStateWithBalances(
  id: string,
): Promise<PoolStateWithBalances>

Parameters

Returns

Promise<PoolStateWithBalances>;

PoolStateWithBalancesopen in new window - State of given pool including token balances and pool shares.

# nestedPools.fetchPoolState

Finds state of a set of nested pools.

fetchNestedPoolState(id: string): Promise<NestedPoolState>

Parameters

Returns

Promise<NestedPoolState>;

NestedPoolStateopen in new window - state of a set of nested pools.

# sorSwapPaths.fetchSorSwapPaths

Finds optimized swap paths for a given swap config.

fetchSorSwapPaths(sorInput: SorInput): Promise<Path[]>

Parameters

Returns

Promise<Path[]>;

Path[]open in new window - optimized swap paths for the given swap.

# Utils

Helper functions.

# calculateProportionalAmounts

Given pool balances (including BPT) and a reference token amount, it calculates all other amounts proportional to the reference amount.

Example

See calculateProportionalAmounts exampleopen in new window.

calculateProportionalAmounts(
  pool: {
    address: Address;
    totalShares: HumanAmount;
    tokens: {
      address: Address;
      balance: HumanAmount;
      decimals: number
    }[];
  },
  referenceAmount: InputAmount,
): {
  tokenAmounts: InputAmount[];
  bptAmount: InputAmount;
}

Parameters

Returns

{
  tokenAmounts: InputAmount[];
  bptAmount: InputAmount;
}

Amounts proportional to the reference amount.

# Permit2 Helper

Balancer v3 handles token approval through Pemit2 and this helper facilitates Permit2 signature generation.

Each operation (i.e. addLiquidity, addLiquidityNested, addLiquidityBoosted and swap) has its own method that leverages the same input type of the operation itself in order to simplify signature generation.

Example

See addLiquidityWithPermit2Signature exampleopen in new window.

Function

static async signAddLiquidityApproval(
    input: AddLiquidityBaseBuildCallInput & {
        client: PublicWalletClient;
        owner: Address;
        nonces?: number[];
        expirations?: number[];
    },
): Promise<Permit2>

Parameters

Returns

Promise<Permit2>;

Permit2open in new window - Permit2 object with metadata and encoded signature

# Permit Helper

Balancer v3 conforms with EIP-2612 and this helper facilitates Permit signature generation.

Each operation (i.e. removeLiquidity, removeLiquidityNested and removeLiquidityBoosted) has its own method that leverages the same input type of the operation itself in order to simplify signature generation.

Example

See removeLiquidityWithPermitSignature exampleopen in new window.

Function

static signRemoveLiquidityApproval = async (
    input: RemoveLiquidityBaseBuildCallInput & {
        client: PublicWalletClient;
        owner: Hex;
        nonce?: bigint;
        deadline?: bigint;
    },
): Promise<Permit>

Parameters

Returns

Promise<Permit>;

Permitopen in new window - Permit object with metadata and encoded signature