Cheat Sheet
0x Protocol Version​
We are currently on v4 of the 0x protocol
Swap API v1 Endpoints​
- Ethereum (Mainnet): https://api.0x.org/
- Ethereum (Sepolia): https://sepolia.api.0x.org/
- Arbitrum: https://arbitrum.api.0x.org/
- Avalanche: https://avalanche.api.0x.org/
- Base: https://base.api.0x.org/
- Binance Smart Chain: https://bsc.api.0x.org/
- Celo: https://celo.api.0x.org/
- Fantom: https://fantom.api.0x.org/
- Optimism: https://optimism.api.0x.org/
- Polygon: https://polygon.api.0x.org/
Gasless API v1 Endpoints​
Gasless API v1 is supported on the following chains via https://api.0x.org/. Select the chain in your request by providing the corresponding chain id with the 0x-chain-id header.
| Chain | Chain ID |
|---|---|
| Ethereum (Mainnet) | 1 |
| Polygon | 137 |
| Arbitrum | 42161 |
| Base | 8453 |
| Optimism | 10 |
Orderbook API Endpoints​
- Ethereum (Mainnet): https://api.0x.org/
- Polygon: https://polygon.api.0x.org/
- Binance Smart Chain: https://bsc.api.0x.org/
Exchange Proxy Addresses​
This is the primary contract for all interactions with the protocol. It is also the allowance-target/spender/operator for any ERC20, ERC721, and ERC1155 assets being traded. For most networks the address is identical, but be aware that a small number (marked with a *) are slightly different. The ABI can be found in the protocol repo's IZeroEx.json file. All 0x contract addresses can be found in the protocol repo's addresses.json file.
- Ethereum (Mainnet):
0xdef1c0ded9bec7f1a1670819833240f027b25eff - Ethereum (Sepolia):
0xdef1c0ded9bec7f1a1670819833240f027b25eff* - Polygon:
0xdef1c0ded9bec7f1a1670819833240f027b25eff - Binance Smart Chain:
0xdef1c0ded9bec7f1a1670819833240f027b25eff - Optimism:
0xdef1abe32c034e558cdd535791643c58a13acc10* - Fantom:
0xdef189deaef76e379df891899eb5a00a94cbc250* - Celo:
0xdef1c0ded9bec7f1a1670819833240f027b25eff - Avalanche:
0xdef1c0ded9bec7f1a1670819833240f027b25eff - Arbitrum:
0xdef1c0ded9bec7f1a1670819833240f027b25eff - Base:
0xdef1c0ded9bec7f1a1670819833240f027b25eff
Ancillary Contract Addresses​
These contracts are used within the 0x ecosystem but are not intended for direct interaction with users except in rare circumstances. They are less likely to remain fixed (compared to the Exchange Proxy Address). The latest addresses can be found in the protocol repo's addresses.json file. A subset of commonly used addresses can be found in contract-addresses.md.
0x Order Types​
An order is a message passed into the 0x Protocol to facilitate a trade (see How does 0x work?). The order types that we support include:
| Order Type | Summary | Order Structure | Supported Token Trade Types |
|---|---|---|---|
| Limit Orders | These are the standard 0x Order, which encodes a possible trade between a maker and taker at a fixed price. | Limit Order Structure | ERC20 <-> ERC20 trade |
| RFQ Orders | These are a stripped down version of standard limit orders, supporting fewer fields and a leaner settlement process. These orders are fielded just-in-time, directly from market makers, during the construction of a swap quote on 0x API, and can be filled through the fillRfqOrder() function on the Exchange Proxy. | RFQ Order Structure | ERC20 <-> ERC20 trade |