# Network Information **Chain IDs:** * Mainnet: `1027303` (`0xface7` in hex) * Sepolia: `16436858` (`0xface7a` in hex) **Block Parameters:** * Block time: 12 seconds (same as Ethereum) * Gas limit: 200 million gas per block **Block Explorers:** * Mainnet: * Sepolia: **RPC Endpoints:** * Mainnet: * Sepolia: These endpoints support all read-only Ethereum JSON-RPC methods: * `eth_estimateGas` - Estimate gas for transactions * `eth_getBalance` - Query FCT balances * `eth_getBlockByNumber` - Retrieve block data * `eth_call` - Execute read-only contract calls * And all other standard read methods **Sending Transactions:** Facet transactions are sent through Ethereum L1. See [Sending Transactions](/immutable-sequencing/sending-transactions.md) for details. **Pre-deployed Contracts:** See [Genesis Contracts](/reference/genesis-contracts.md) for the full list of contracts available at genesis. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.facet.org/reference/network-information.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.