brk_indexer

Parses and indexes the entire Bitcoin blockchain so you can look up any block, transaction, input, output, or address by index in O(1).

How It's Organized

Every entity gets a sequential index in blockchain order:

Block 0, 1, 2, ... → height
Transaction 0, 1, 2, ... → txindex
Input 0, 1, 2, ... → txinindex
Output 0, 1, 2, ... → txoutindex
Address 0, 1, 2, ... → addressindex (per address type)

Data is stored in append-only vectors keyed by these indexes. Each block also stores the first index of each entity type it contains (e.g. first_txindex, first_txoutindex), so you can find all transactions, inputs, outputs, and addresses in any block in O(1).

What's Indexed

Per Block (keyed by height)

Block hash, timestamp, difficulty, size, weight

Per Transaction (keyed by txindex)

Txid, version, locktime, base size, total size, RBF flag, block height

Per Input (keyed by txinindex)

Spent outpoint, containing txindex, and the spent output's type and address index

Per Output (keyed by txoutindex)

Value in satoshis, script type, address index within that type, containing txindex

Script types: P2PK (compressed/uncompressed), P2PKH, P2SH, P2WPKH, P2WSH, P2TR, P2A, P2MS, OP_RETURN, Empty, Unknown

Per Address (keyed by addressindex, one set per type)

Raw address bytes (20-65 bytes depending on type: pubkey, pubkey hash, script hash, witness program, etc.)

Address types each get their own index space: P2PK65, P2PK33, P2PKH, P2SH, P2WPKH, P2WSH, P2TR, P2A

Per Non-Address Script (OP_RETURN, P2MS, Empty, Unknown)

Containing txindex

Key-Value Stores

On top of the vectors, key-value stores enable lookups that aren't sequential:

Store	Purpose
txid prefix → txindex	Look up a transaction by its txid
block hash prefix → height	Look up a block by its hash
address hash → addressindex	Look up an address (per type)
addressindex + txindex	All transactions involving an address
addressindex + outpoint	Unspent outputs for an address (live UTXO set)
height → coinbase tag	Miner-embedded message per block

How It Works

Block metadata — store block hash, difficulty, timestamp, size, weight
Compute TXIDs — parallel SHA256d across all transactions
Process outputs — classify script types, extract addresses, detect new unique addresses
Process inputs — resolve spent outpoints, look up address info
Finalize — update address stores, UTXO set mutations, push all vectors
Snapshot — periodic flush to disk for crash recovery

Reorg handling is built-in: on chain reorganization, the indexer rolls back to the last valid state.

Performance

Version	Machine	Time	Disk	Peak Disk	Memory	Peak Memory
v0.2.0-pre	MBP M3 Pro (36GB, internal SSD)	2h40	239 GB	302 GB	5.9 GB	13 GB
v0.1.0-alpha.0	Mac Mini M4 (16GB, external SSD)	4.9h	233 GB	303 GB	5.4 GB	11 GB

Full benchmark data: bitcoinresearchkit/benches

Recommended: mimalloc v3

Use mimalloc v3 as the global allocator to reduce memory usage.

Built On

vecdb for append-only vectors — integer-compressed (PcoVec) or raw bytes (BytesVec)
brk_iterator for block iteration
brk_store for key-value storage (fjall LSM)
brk_types for domain types