Track mempool state, estimate transaction fees via projected block building, and query address mempool activity. Updates automatically with 1-second sync cycles.

Key Features

Projected blocks: Simulates Bitcoin Core's block template algorithm with CPFP awareness
Fee estimation: Multi-tier fee recommendations (fastest, half-hour, hour, economy, minimum)
Address tracking: Maps addresses to their pending transactions
Dependency handling: Respects transaction ancestry for accurate fee calculations
Rate-limited rebuilds: Throttles expensive projections to 1/second

Core API

let mempool = Mempool::new(&rpc_client);

// Start background sync loop
std::thread::spawn(move || mempool.start());

// Query current state
let fees = mempool.get_fees();
let info = mempool.get_info();
let blocks = mempool.get_block_stats();
let snapshot = mempool.get_snapshot();

// Address lookups
let tracker = mempool.get_addresses();

Fee Estimation

Returns RecommendedFees with sat/vB rates for different confirmation targets:

fastest_fee - Next block (index 0)
half_hour_fee - ~3 blocks (index 2)
hour_fee - ~6 blocks (index 5)
economy_fee - ~8 blocks (index 7, last projected block)
minimum_fee - Relay minimum

Block Projection

Builds projected blocks by:

Constructing transaction dependency graph
Calculating effective fee rates (including ancestors)
Selecting transactions greedily by ancestor-aware fee rate
Partitioning into 1MB vsize blocks

Built On

brk_error for error handling
brk_rpc for mempool RPC calls
brk_types for MempoolInfo, MempoolEntryInfo, RecommendedFees