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  • Introduction
    • Welcome
    • Supported Chains and Providers
    • Demo Apps
    • FAQ
    • API Issues & Error Codes
    • Need Help?
  • Swap API
    • Introduction
    • FAQ
  • Gasless API
    • Introduction
    • Gasless FAQ
  • Cross-Chain API
    • Introduction
    • Learn More
  • Trade Analytics API
    • Introduction
    • Transaction Data
    • Trade Analytics FAQ
  • Core Concepts
    • Introduction to 0x
    • 0x Cheat Sheet
    • Contracts
    • Order Types
    • Glossary
    • White Paper
    • Transaction Data
  • Developer Resources
    • Bounties
    • Rate Limits
    • System Status
  • Upgrading
    • Overview
    • Upgrading to Swap v2
    • Upgrading to Gasless v2
  • Need Help?
    • FAQ
    • API Issues & Error Codes
    • Contact Support
    • Contact Sales
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On this page
  • What is Swap API?
  • Why use Swap API?
  • Try it out
  • How does it work?
  • Supported Chains
  • Get Started
Swap API

Introduction

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Get Started with Swap API

Built with

Prefer to watch a video or see a code demo instead? Jump to 0x Videos or 0x Code Examples.

What is Swap API?

Swap API is a professional-grade DEX aggregation and smart order routing API that lets you add crypto trading with a single API. It sources the best real-time prices from 150+ public and private liquidity providers across supported chains.

Swap Widget

Want to build a gasless trading app? Check out Gasless API instead.

Why use Swap API?

Swap API is designed to protect your users, streamline integration for developers, and unlock new revenue opportunities for your team.

  • ⛓️ Multi-chain liquidity: Tap into deep liquidity across major networks. See supported chains.
  • 🤑 Built-in monetization: Earn fees on every swap.
  • 🛡️ User protection: Our smart contracts reduce allowance risk by supporting modern standards like AllowanceHolder and Permit2 for safer token approvals.
  • ↩️ Reliable execution: We offer some of the lowest revert rates in the industry.
  • 💰 Exclusive RFQ liquidity: Access private, off-chain RFQ quotes with 0 slippage.
  • 🚀 Developer-friendly: Easy to integrate, customizable, and designed to find the best price with a single request.

Try it out

Run the request below to get a live quote for selling 100,000 WETH for DAI:

$# Sell 100,000 WETH for DAI
$# Taker address is vitalik.eth
$# Replace "YOUR_API_KEY" with your actual API key from https://dashboard.0x.org/create-account
$curl --request GET \
>  --url "https://api.0x.org/swap/allowance-holder/quote?sellAmount=100000000000000000000000&taker=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045&chainId=1&sellToken=0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2&buyToken=0x6b175474e89094c44da98b954eedeac495271d0f" \
>  --header "0x-api-key: YOUR_API_KEY" \
>  --header "0x-version: v2"

You’ll receive an unsigned Ethereum transaction that can be signed and submitted directly to a node. Learn more about the response parameters in the API docs.

Expand to see response
${
>    "allowanceTarget": "0x0000000000001ff3684f28c67538d4d072c22734",
>    "blockNumber": "23187566",
>    "buyAmount": "235932519449815263461168645",
>    "buyToken": "0x6b175474e89094c44da98b954eedeac495271d0f",
>    "fees": {
>        "integratorFee": null,
>        "zeroExFee": {
>            "amount": "326467223589357163093426",
>            "token": "0x6b175474e89094c44da98b954eedeac495271d0f",
>            "type": "volume"
>        },
>        "gasFee": null
>    },
>    "issues": {
>        "allowance": {
>            "actual": "0",
>            "spender": "0x0000000000001ff3684f28c67538d4d072c22734"
>        },
>        "balance": {
>            "token": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>            "actual": "0",
>            "expected": "100000000000000000000000"
>        },
>        "simulationIncomplete": false,
>        "invalidSourcesPassed": []
>    },
>    "liquidityAvailable": true,
>    "minBuyAmount": "233569649951068991418492945",
>    "route": {
>        "fills": [
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "source": "Uniswap_V3",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "source": "Uniswap_V3",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "source": "Curve",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "source": "Curve",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "source": "Uniswap_V4",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "source": "Uniswap_V2",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "source": "SushiSwap",
>                "proportionBps": "500"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "source": "RingSwap",
>                "proportionBps": "500"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
>                "source": "Uniswap_V3",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
>                "source": "Uniswap_V2",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
>                "source": "SushiSwap",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "Uniswap_V3",
>                "proportionBps": "499"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "Uniswap_V3",
>                "proportionBps": "249"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "Uniswap_V3",
>                "proportionBps": "499"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "Curve",
>                "proportionBps": "249"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "Uniswap_V4",
>                "proportionBps": "249"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "Uniswap_V4",
>                "proportionBps": "756"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "Uniswap_V2",
>                "proportionBps": "499"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "Uniswap_V4",
>                "proportionBps": "249"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "source": "Uniswap_V3",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "source": "Uniswap_V3",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "source": "Uniswap_V3",
>                "proportionBps": "1251"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "source": "Uniswap_V4",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "source": "Uniswap_V2",
>                "proportionBps": "1000"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "source": "PancakeSwap_V3",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "to": "0xf939e0a03fb07f59a73314e73794be0e57ac1b4e",
>                "source": "Curve",
>                "proportionBps": "250"
>            },
>            {
>                "from": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "to": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "source": "Uniswap_V3",
>                "proportionBps": "174"
>            },
>            {
>                "from": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "Uniswap_V3",
>                "proportionBps": "2036"
>            },
>            {
>                "from": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "0x_RFQ",
>                "proportionBps": "290"
>            },
>            {
>                "from": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
>                "source": "Uniswap_V3",
>                "proportionBps": "104"
>            },
>            {
>                "from": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
>                "source": "Curve",
>                "proportionBps": "2955"
>            },
>            {
>                "from": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "to": "0xf939e0a03fb07f59a73314e73794be0e57ac1b4e",
>                "source": "Curve",
>                "proportionBps": "366"
>            },
>            {
>                "from": "0xf939e0a03fb07f59a73314e73794be0e57ac1b4e",
>                "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "source": "Curve",
>                "proportionBps": "616"
>            },
>            {
>                "from": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
>                "source": "Maker_PSM",
>                "proportionBps": "6191"
>            }
>        ],
>        "tokens": [
>            {
>                "address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>                "symbol": "WETH"
>            },
>            {
>                "address": "0x2260fac5e5542a773aa44fbcfedf7c193bc2c599",
>                "symbol": "WBTC"
>            },
>            {
>                "address": "0xdac17f958d2ee523a2206206994597c13d831ec7",
>                "symbol": "USDT"
>            },
>            {
>                "address": "0xf939e0a03fb07f59a73314e73794be0e57ac1b4e",
>                "symbol": "crvUSD"
>            },
>            {
>                "address": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
>                "symbol": "USDC"
>            },
>            {
>                "address": "0x6b175474e89094c44da98b954eedeac495271d0f",
>                "symbol": "DAI"
>            }
>        ]
>    },
>    "sellAmount": "100000000000000000000000",
>    "sellToken": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
>    "tokenMetadata": {
>        "buyToken": {
>            "buyTaxBps": "0",
>            "sellTaxBps": "0"
>        },
>        "sellToken": {
>            "buyTaxBps": "0",
>            "sellTaxBps": "0"
>        }
>    },
>    "totalNetworkFee": "31754911939128290",
>    "transaction": {
>        "to": "0x0000000000001ff3684f28c67538d4d072c22734",
>        "data": "0x2213bc0b000000000000000000000000df31a70a21a1931e02033dbba7deace6c45...truncated...",
>        "gas": "87021770",
>        "gasPrice": "364907677",
>        "value": "0"
>    },
>    "zid": "0xf7107a43f9382b57c6b0c4e7"
>}

How does it work?

Swap API is a professional-grade DEX aggregator and smart order-routing API. It pulls prices from 150+ liquidity sources—both public AMMs and private market makers—across multiple blockchains to return the best executable price.

Below is a high-level diagram showing how Swap API works under the hood:

How 0x works

1A user requests a quote.
2

Swap API simultaneously (a) fetches a quote from AMM and (b) requests quotes from market makers.

3Market makers respond with signed quotes at their discretion.
4

Swap API aggregates all quotes, compares them, and returns the best price.

5

If the user accepts, the signed order is submitted on-chain and settled via 0x.

For more details about how 0x orders are executed, check out How does 0x work?

Under the hood, Swap API performs a series of tasks:

  • Queries prices from multiple DEXs and market makers and aggregates the liquidity from the queried sources to provide the best price possible. Think of how Google flights aggregates flight prices for a certain time and date to help you find the best price, /swap similarly helps you find the best price across DeFi liquidity sources.
  • Swap API’s smart order routing algorithm splits up your transaction across different sources to maximize the overall return on your swap. Read more about smart order routing here.
  • The response returned by Swap API is a valid unsigned Ethereum transaction that can be signed and submitted directly to an Ethereum node. Easily execute using the transaction using the web3 library of your choice.

Supported Chains

Swap API supports multiple blockchain networks. Refer to the Supported Chains page for the full list of currently supported networks and chain IDs.

Get Started

Create an account and get live API keys on the 0x Dashboard.

Next, Get Started with Swap API