# Reference

*SDK, CLI, APIs, and network details*

Exact options, commands, endpoints, and network values. For step-by-step guides, see [Build](/build.md).

## Payments

* [radius-sdk](/reference/radius-sdk.md): options, helpers, receipts, and error codes for the TypeScript SDK.
* [radius-cli](/reference/radius-cli.md): commands for local wallets, transfers, and paying x402 endpoints.
* [x402 facilitator API](/reference/facilitator-api.md): verify and settle endpoints of the Radius facilitator.

## Network

* [Network and RPC](/reference/network.md): chain IDs, RPC endpoints, explorers, and faucets.
* [Fees](/reference/fees.md): gas pricing, transaction costs, and Turnstile conversion.
* [Contract addresses](/reference/contract-addresses.md): stablecoin and utility contracts on testnet and mainnet.
* [Ethereum compatibility](/reference/ethereum-compatibility.md): where Radius differs from Ethereum.

## JSON-RPC

* [Overview](/reference/json-rpc.md): how the JSON-RPC interface behaves on Radius.
* [Methods](/reference/json-rpc/methods.md): supported methods, parameters, and differences.