Gas and blocks

Gas

const gas = await provider.getGasData?.("base");

Etherscan and Blockscout on their EVM chains, Mempool on Bitcoin and Litecoin, Horizon on Stellar. Nobody else, and the reasons are on the provider pages: Blockstream's fee estimates don't match the recommendation shape, WhatsOnChain and Blockbook quote per kilobyte, Peppool has no fee endpoint, Arweave prices storage per byte rather than per gas unit, Haskoin keeps no fee estimates, and the rest simply don't publish fee data.

type GasUnit = "gwei" | "sat/vB" | "litoshi/vB" | "micro-lamports/CU" | "MIST" | "stroops";

interface GasData {
  chain: ChainKey;
  unit: GasUnit; // shared by every price field below
  safeGasPrice?: string;
  proposedGasPrice?: string;
  fastGasPrice?: string;
  baseFee?: string;
  priorityFee?: string;
}

The unit is part of the answer. gwei on EVM chains, sat/vB on Bitcoin, litoshi/vB on Litecoin, stroops per operation on Stellar, where Horizon's fee stats give the ledger base fee, the fee most operations paid over the last five ledgers as safe and the 95th percentile as fast, with no middle tier. Fields a provider doesn't quote are absent, not zero.

Blocks

const block = await provider.getBlockInfo?.(18_000_000, "ethereum");

Etherscan, Blockscout, Blockchair, Mempool on Bitcoin and Litecoin, Blockstream, Solscan, TRONSCAN, the Arweave gateway, dcrdata, WhatsOnChain, Blockbook, Haskoin, eCash Explorer and Horizon, where a block is a ledger. TONAPI and Blockberry don't expose a lookup that fits a single block number, Helius and Koios don't serve blocks, and Aptos serves nothing.

interface BlockInfo {
  number: number;
  hash: string;
  parentHash: string;
  timestamp: string; // ISO
  miner: string;
  gasUsed: string;
  gasLimit: string;
  txCount: number;
  baseFee?: string; // EIP-1559 chains
}

On chains without gas the two gas fields are still there, so a consumer can treat them as always present. Most providers outside EVM put "0" in both, Arweave, Decred and Stellar included. Three don't. Mempool and Blockstream put the block's size in gasUsed and its weight in gasLimit, and the explorer labels them as such. Solscan puts the block's fee rewards, in lamports, in gasUsed. A Stellar ledger also carries its base fee in stroops in baseFee.

CLI

explorers gas
explorers gas -c base
explorers gas -c bitcoin
explorers block 18000000
explorers block 1994692 -c arweave
explorers block 1000 -c dcr