Today’s meditation is about optimizing your Forta bot for gas efficiency, using as little compute as possible to stay fast, light, and affordable.
Why Gas Efficiency is important
Even though Forta bots don’t execute on-chain, they simulate or parse transactions and logs.
Bots are executed by scan nodes, and so inefficient logic can:
Drain node resources
Increase latency in detection
Lead to missed alerts
Your requests may be slowed down or delayed
Cost more if hosted yourself
Efficiency = faster detection + lower costs + better reputation.
What Consumes Resources in a Forta Bot?
Principles of Efficient Bot Design
Think like a minimalist security monk. Only compute what you must.
1. Early exits
if (tx.value < THRESHOLD) return [];
Avoid logic when you can skip processing entirely.
2. Narrow event filters
txEvent.filterLog(MY_EVENT_ABI, CONTRACT_ADDRESS)
Instead of parsing all logs, filter by exact event + address.
3. Avoid unnecessary JSON parsing
Avoid converting logs to strings or decoding ABI data unless it’s necessary.
4. Limit state writes
Only store values that you will use in future blocks.
state.set("lastLargeTx", timestamp);
5. Cache expensive lookups
If you check a contract’s type repeatedly, cache the result to reuse it later:
const isERC20 = await isERC20Contract(addr);
// cache result to avoid calling again
6. Avoid redundant alerts
Use limiting or uniqueness logic to avoid saturation.
if (state.alreadyAlerted(tx.hash)) return [];
Monitor Bot Resource Usage
You can check:
Scan Node Logs (if self-hosted)
Forta Explorer bot stats
Gas profiler CLI (coming soon)
Track:
Average execution time per tx/block
Memory usage
Alert frequency
Practical Example – Before and After
This would be Inefficient:
txEvent.logs.forEach(log => {
// decode manually
const decoded = web3.eth.abi.decodeLog(...);
if (decoded.to == TARGET) ...
});
This would be Efficient:
const logs = txEvent.filterLog(MY_ABI, CONTRACT);
logs.forEach(log => {
if (log.args.to == TARGET) ...
});
Key Concepts Recap
Gas efficiency makes your bot faster, cheaper, and more reliable
Use early returns, precise filtering, and limit how often you write to state — they all help optimize performance
Avoid wasteful loops, log parsing and excessive state saves
Forta rewards efficient bots
In Lesson 20, we will step back and build a monitoring strategy across chains, contracts, and all the places where attacks could potentially happen.
Until next meditation,
The Blockchain Security Monk