Other Components

Fee Policy

Controls initial fee suggestion and replacement fee bumping.

Fees are derived from the chain: maxFee = baseFee * base_multiplier + tip, where the tip comes from eth_maxPriorityFeePerGas. The gwei values are floors, not the primary source.

Config Key	Meaning
fees.base_multiplier	Headroom for the base fee rising while the tx waits
fees.min_priority_gwei	Lower bound for the tip (Polygon typically wants 25-30)
fees.min_maxfee_gwei	Lower bound for maxFeePerGas
fees.replacement_factor	Fee bump factor, never applied below the 10% nodes require
tx.max_replacements	Limit of fee bump attempts

Implement a custom policy by binding a new class to FeePolicy:

use Farbcode\LaravelEvm\Support\FeeSnapshot;

class MyAdaptivePolicy implements FeePolicy
{
    public function suggest(FeeSnapshot $snapshot): array
    {
        return [$priorityWei, $maxFeeWei];   // maxFee must be >= priority
    }

    public function replace(int $oldPriority, int $oldMax): array
    {
        return [$priorityWei, $maxFeeWei];   // both at least 10% above the old values
    }
}

$this->app->singleton(FeePolicy::class, fn() => new MyAdaptivePolicy());

Nonce Management

Local nonce memory prevents collision during sequential sends. Transactions for one signing address are serialised by a cache lock, so a second worker cannot race the nonce; for horizontal scaling across machines add a distributed (Redis/DB) manager.

The cache is dropped and re-read from the chain whenever it can no longer be trusted - a failed broadcast, or a transaction that was never mined. A custom NonceManager must implement invalidate(string $address) for that.

Signer

Owns the key and performs the signing, so nothing outside it ever holds the key. Current driver: private_key.

A KMS, HSM or remote signer is a plain implementation of the contract:

class KmsSigner implements Signer
{
    public function getAddress(): string { /* ... */ }

    public function sign(array $fields): string
    {
        // return the raw 0x-prefixed payload for eth_sendRawTransaction
    }
}

Health Snapshot

Quick connectivity check:

$status = \Farbcode\LaravelEvm\Facades\EvmRpc::health();

Reports chain id and latest block per configured endpoint, with a matchesConfiguredChain flag so a url pointing at the wrong chain is visible. Endpoint credentials are redacted.

Encoding Helpers

Use Encoding::stringToBytes32('text') for static bytes32 arguments.

Security Considerations

Concern	Recommendation
Private key exposure	Keep in env; the signer never hands it out
RPC credentials	Logged redacted; keep .env out of git
Nonce race	Single worker per address
RPC reliability	Configure multiple endpoints
Fee underpricing	Monitor TxReplaced frequency