Assemble

The /sor/assemble endpoint is used after calling /sor/quote/v3 and receiving a pathId. The pathId is used in the assemble request to return the call data to be executed onchain.

A quote is valid for 60 seconds. If it is not assembled within that time, the path must be re-quoted.
Use the data from this endpoint exactly as provided — modifying calldata can lead to irreversible loss of funds.
Odos does not provide support for transactions using modified calldata.

---

Request Body

Parameter	Description	Required
userAddr	Address of the user who requested the quote.	Yes
pathId	ID of the path returned from /sor/quote/{version}.	Yes
simulate	Simulate the transaction to ensure it executes successfully. Increases response time. Defaults to false.	No
receiver	Optional address to receive transaction output (default = userAddr).	No

---

Response Body

Parameter	Description
deprecated	Message if endpoint or fields are deprecated.
blockNumber	Block number the quote was generated for.
gasEstimate	Naive gas estimate.
gasEstimateValue	USD value of the gas estimate.
inputTokens	List of input token addresses and amounts.
outputTokens	List of output token addresses and amounts.
netOutValue	Net USD value of output tokens after gas.
outValues	Output values corresponding to output tokens.
transaction	Transaction object required for execution.
simulation	Results of transaction simulation.

---

Transaction Object

This structure can be signed by a wallet and executed on the Odos router contract.
In a smart contract, use the following call pattern:

(bool success, bytes memory result) = router.call{value: $ethInput}(data);

Where $ethInput is 0 unless the native coin is used as input.
ERC20 inputs must be approved to the router address beforehand.
The router address is provided in the to field or can be retrieved from /info/router/{version}/{chain_id}.

Parameter	Description
chainId	Chain ID for execution.
gas	Suggested gas limit (2x naive estimate or +10% above simulation).
gasPrice	Gas price used during path generation.
value	Input amount of gas token (0 if gas token is not an input).
to	Odos router address to execute against.
from	Source wallet executing the transaction.
data	Encoded calldata payload for the Odos router.
nonce	Standard Ethereum nonce.

---

Simulation Object

Result of the transaction simulation.

Parameter	Description
isSuccess	Indicates if the transaction executed successfully.
amountsOut	Token output amounts from the simulation.
simGasUsed	Gas used during the simulation.
gasEstimate	Gas estimate from eth_estimateGas.
simulationError	Error details if the simulation failed.

---

Example: Assemble a Transaction

JavaScript

import 'dotenv/config';
import fetch from 'node-fetch';

const assembleUrl = 'https://enterprise-api.odos.xyz/sor/assemble';

const assembleRequestBody = {
  userAddr: '0x...',        // same user address used in quote step
  pathId: quote.pathId,     // from /sor/quote response
  simulate: true
};

const response = await fetch(assembleUrl, {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'x-api-key': process.env.ODOS_API_KEY
  },
  body: JSON.stringify(assembleRequestBody)
});

const assembled = await response.json();
console.log(assembled.transaction);

Python

import os
import requests
from dotenv import load_dotenv

load_dotenv()

assemble_url = 'https://enterprise-api.odos.xyz/sor/assemble'

assemble_request_body = {
    "userAddr": "0x...",
    "pathId": quote["pathId"],
    "simulate": True
}

headers = {
    "Content-Type": "application/json",
    "x-api-key": os.getenv("ODOS_API_KEY")
}

response = requests.post(assemble_url, json=assemble_request_body, headers=headers)
assembled = response.json()
print(assembled["transaction"])

---

Example Response

{
  "blockNumber": 23619524,
  "gasEstimate": 214504,
  "gasEstimateValue": 1.12,
  "transaction": {
    "to": "0x221a4c9e54baebd678ff1823e4fca2ac3685ca64",
    "from": "0x5AD89031aAfFe2F82dF3b98Fa4181E08B5dCFF9C",
    "data": "0x12ab34cd...",
    "chainId": 8453,
    "gas": 235000,
    "gasPrice": "1000000000",
    "value": "0",
    "nonce": 112
  },
  "simulation": {
    "isSuccess": true,
    "amountsOut": ["1833893"],
    "simGasUsed": 203421,
    "gasEstimate": 214504,
    "simulationError": null
  }
}