@rpc-bastion/fees

A priority-fee oracle with pluggable providers and quorum logic, plus a helper to apply an estimate to a web3.js v2.0 (@solana/kit) transaction message.

Oracle

import { createFeeOracle, nativeFeeProvider, heliusFeeProvider, staticFeeProvider } from '@rpc-bastion/fees';

const oracle = createFeeOracle({
  providers: [
    heliusFeeProvider({ rpcUrl: HELIUS_URL }),
    nativeFeeProvider({ rpc }),                 // your resilient @rpc-bastion/core rpc
    staticFeeProvider({ values: 10_000n }),     // offline floor
  ],
  strategy: 'median',          // 'first-success' | 'median' | 'max'
  cacheTtlMs: 2_000,
  timeoutPerProviderMs: 1_500,
  fallbackEstimate: 10_000n,
  bus,                         // optional @rpc-bastion/core event bus
});

const fee = await oracle.estimate({ level: 'high' });
// { microLamportsPerCu, level, source, fetchedAt }

The oracle never throws while any provider succeeds. If they all fail it returns fallbackEstimate and emits fee.estimate with source: 'fallback' (treat that as a warning), and does not cache it.

| Provider | Source | |---|---| | nativeFeeProvider | getRecentPrioritizationFees → percentiles (p50/p75/p90/p99 → levels). The dependable fallback. | | heliusFeeProvider | Helius getPriorityFeeEstimate | | tritonFeeProvider | Triton / RPCPool fee API (experimental) | | staticFeeProvider | Fixed values (tests / offline / floors) |

Applying a fee

import { applyFeeToTransactionMessage } from '@rpc-bastion/fees';

// Fixed limit:
const withFee = await applyFeeToTransactionMessage(message, fee, { computeUnitLimit: 200_000 });

// Or simulate to size the limit (sets limit = ceil(units × 1.1)):
const sized = await applyFeeToTransactionMessage(message, fee, { computeUnitLimit: 'simulate', rpc });

It sets SetComputeUnitPrice to fee.microLamportsPerCu and SetComputeUnitLimit to the chosen limit, replacing any existing ComputeBudget limit/price instructions and placing the new pair at the front.