eth_getBlockByNumber

Returns information about a block identified by its number.

Tip

Flashblocks: call https://mainnet-preconf.base.org with "pending" to fetch the live Flashblock in progress — a real block object refreshed every ~200ms with new pre-confirmed transactions. The response shape is identical; the block is simply not yet sealed.

Parameters

Position	Name	Type	Description
1	block	string	Block number in hex, or "latest", "pending", "safe", "finalized", "earliest". Pass "pending" on a Flashblocks endpoint to get the in-progress block. Required.
2	fullTransactions	boolean	When true, returns full transaction objects; when false, returns only transaction hashes. Required.

Returns

result (object or null if no block was found):

Field	Type	Description
number	string	Block number in hex. null when pending.
hash	string	Block hash. null when pending.
parentHash	string	Hash of the parent block.
nonce	string	PoW nonce. Always "0x0000000000000000" on Base (PoS).
sha3Uncles	string	Hash of the uncles list. Always empty on Base.
logsBloom	string	Bloom filter for the block’s logs.
transactionsRoot	string	Root of the transaction trie.
stateRoot	string	Root of the final state trie.
receiptsRoot	string	Root of the receipts trie.
miner	string	Address of the fee recipient (coinbase).
difficulty	string	Always "0x0" on Base (PoS).
totalDifficulty	string	Always "0x0" on Base (PoS).
extraData	string	Arbitrary data field set by the sequencer.
size	string	Block size in bytes (hex).
gasLimit	string	Maximum gas allowed in this block (hex).
gasUsed	string	Total gas used in this block (hex).
timestamp	string	Unix timestamp (hex).
transactions	array	Array of transaction hashes or full transaction objects.
uncles	array	Always [] on Base.
withdrawals	array	Always [] on Base.
baseFeePerGas	string	EIP-1559 base fee per gas (hex).
blobGasUsed	string	Total blob gas used (EIP-4844, hex).
excessBlobGas	string	Excess blob gas for blob fee calculation (EIP-4844, hex).
parentBeaconBlockRoot	string	Parent beacon block root (EIP-4788).
requestsHash	string	Hash of requests (EIP-7685).

Flashblock-specific response fields

When you query "pending" on a Flashblocks endpoint, the response is a live snapshot of the block being built. A few fields behave differently:

Field	Standard latest	Flashblocks pending
number	Sealed block number	Current block number (being built)
hash	Final block hash	Hash of the partial block at this Flashblock index
gasUsed	Final gas used	Cumulative gas used up to this Flashblock
transactions	All sealed transactions	Transactions pre-confirmed so far
blobGasUsed	Final blob gas used	Propagated from cumulative Flashblock state

Example

Request

Standard (latest sealed block)

curl https://mainnet.base.org \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_getBlockByNumber",
    "params": ["latest", false],
    "id": 1
  }'

Flashblocks (pending, live at ~200ms)

curl https://mainnet-preconf.base.org \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_getBlockByNumber",
    "params": ["pending", false],
    "id": 1
  }'

Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "number": "0x158a0e9",
    "hash": "0x5c330e55a190f82ea486b61e5b12e27dfb4fb3cecfc5746886ef38ca1281bce8",
    "parentHash": "0x9edc29b8b0a1e31d28616e40c16132ad0d58faa8bb952595b557526bdb9a960a",
    "timestamp": "0x67bf8332",
    "gasLimit": "0x3938700",
    "gasUsed": "0xab3f",
    "baseFeePerGas": "0xfa",
    "transactions": ["0x7ef8f8a0..."],
    "withdrawals": [],
    "miner": "0x4200000000000000000000000000000000000011"
  }
}