@ekubo/yul-router-sdk

Builds the packed swap calldata for the Ekubo Yul Router on EVM chains, and the calldata for reading a price quotation for that same route.

The router takes custom packed calldata rather than a conventional ABI-encoded function call. This SDK is what produces those bytes: you describe a route as a list of hops, and it returns the 0x… calldata to send to the router address.

Installation

npm install @ekubo/yul-router-sdk
# or
bun add @ekubo/yul-router-sdk

viem is a peer dependency.

Constructing a swap transaction

encodeRoutes(...) / generateCalldata(...) take a set of multi-hops and return the calldata for the swap. Every multi-hop starts from the same specifiedToken and ends at the same calculatedToken; the router executes them all under one Core lock, aggregates the amounts, applies a single slippage check, and settles once.

import { generateCalldata, YUL_ROUTER_ADDRESS } from "@ekubo/yul-router-sdk";

const data = generateCalldata({
  multiHops: [
    {
      specifiedAmount: 10n ** 18n,
      hops: [{ poolKey, sqrtRatioLimit: MIN_SQRT_RATIO }],
    },
  ],
  specifiedToken: tokenIn,
  calculatedToken: tokenOut,
  calculatedAmountThreshold: minimumOut, // required; guards slippage
  recipient,
});

// Send with any EVM client:
await walletClient.sendTransaction({ to: YUL_ROUTER_ADDRESS, data, value });

calculatedAmountThreshold is mandatory — a positive minimum output for exact-input routes, a negative maximum input for exact-output. Omitting it throws rather than silently encoding an unbounded slippage threshold.

Exact-input amounts are positive; exact-output amounts are negative.

Obtaining a price quotation

generateQuoteCalldata(...) / encodeQuoteCalldata(...) produce the calldata for the router's quote(bytes) entrypoint, which runs the identical route inside a Core lock and returns the resulting amounts without settling. No token balance and no approval are required, and all pool and extension state changes are rolled back.

import { generateQuoteCalldata } from "@ekubo/yul-router-sdk";

const data = generateQuoteCalldata({ multiHops, specifiedToken, calculatedToken });
const { data: result } = await publicClient.call({ to: YUL_ROUTER_ADDRESS, data });
// decodes to (specifiedToken, calculatedToken, specifiedAmount, calculatedAmount)

Direct execution, forwarding, and quoting all return the same four-word tuple for the same route and starting state, so a quotation and the swap built from it stay byte-for-byte comparable.

Hop types

Also exported

• encodeRoute(...) — encode a single route body
• encodeSignedSwapMeta(...) — encode the metadata for a signed exclusive swap
• encodePoolBalanceUpdate(...) — encode a pool balance delta
• calldataSize(...) — byte length of encoded calldata
• YUL_ROUTER_ADDRESS, YUL_ROUTER_ABI, and the sqrt-ratio and threshold bounds

License

See the repository.