We appreciate your interest in building with our APIs. To get an API key and start building for free, please create an account on the 0x Dashboard. You may also check out our enterprise options and contact our team for more custom needs. Our team will review and respond to you.

An app is a self-contained unit for each individual application that you’re building. Each app can have its own unique API keys and configurations.

Swap API is available on Ethereum (Mainnet and Goerli) as well as various EVM chains and L2 solutions, including: Arbitrum, Avalanche, Celo, Binance Smart Chain, Fantom, Optimism and Polygon (Mainnet and Mumbai). Tx Relay API is currently available on Ethereum and Polygon, with support for more EVM chains coming soon. Orderbook API is available on Ethereum, Binance Smart Chain and Polygon.

0x will levy fees on a limited set of tokens that is subject to change. Moreover, the fee may be forfeited on other trade conditions. The fee, when applied, will be returned in each API response.

You can monitor the API usage for your apps on the 0x Dashboard.

The Swap API has a powerful free plan that you can access by creating an account via the 0x Dashboard. However, we also offer paid plans with higher throughput to support you as your user base and transactions grow. You can review and select the perfect plan for your team's needs on our pricing page.

0x also takes an on-chain fee on swaps involving a select few token pairs for the Free and Starter tiers. This fee is charged on-chain to the users of your app during the transaction. If you are on the Growth tier, we completely waive this fee for your customers. In cases where we charge a fee, we'll return the value of the fee in the API response in the zeroExFee parameter. You can find more details about this in the Swap API reference.

For now we only support one user per team account, but we will add support for multiple users in the coming weeks.