Karina Gookin FaSP

#BinanceBlockchainWeek 🔔 *Blockchain Alert Overview*

A _blockchain alert_ is a real‑time notification that informs users or applications when a significant event occurs on a blockchain network. Think of it as a “push‑notification” for the decentralized ledger, helping stakeholders react quickly to changes that matter to them.
Why Alerts Matter
- *Speed* – Blockchains are immutable, but markets and operations move fast. Alerts let you act before a transaction confirms or a price swings.
- *Security* – Immediate notice of suspicious activity (e.g., large transfers, governance votes) can trigger defensive measures.
- *Operational Efficiency* – Automated alerts reduce manual monitoring, saving time and reducing human error.
Common Types of Blockchain Alerts
Type What Triggers It Typical Recipients
Transaction Alert A transaction exceeding a set value or involving a specific address Wallets, exchanges, compliance teams
Block‑Height Alert New block added (e.g., every 10 minutes on Bitcoin) Miners, network monitors
Smart‑Contract Event Emission of a Solidity event (e.g., Transfer, Approval) dApp front‑ends, auditors
Network‑Status Alert Fork, consensus failure, or node disconnection DevOps, validators
Price/ Market Alert Token price crossing a threshold Traders, portfolio managers
Governance Alert Proposal submitted, voting starts, or quorum reached DAO members, community bots
How Alerts Are Delivered
1. *On‑Chain* – Events are emitted by the smart contract and read by off‑chain services (e.g., The Graph, Chainlink).
2. *Off‑Chain Services* – Dedicated alert platforms (e.g., Alchemy Notify, Blocknative, QuickNode) poll the node or subscribe via websockets.
3. *Messaging Channels* – Email, SMS, Telegram, Discord, or webhook endpoints.

*Typical workflow:*
Smart contract emits event → Node broadcasts → Alert service filters → Webhook → Your app or chat bot → User receives notification

Quick Example (Ethereum)
pragma solidity ^0.8.20;

contract Token {
event Transfer(address indexed from, address indexed to, uint256 value);

function transfer(address to, uint256 amount) external {
// ... transfer logic ...
emit Transfer(msg.sender, to, amount);
}
}

- An off‑chain service (e.g., Alchemy) listens for `Transfer` events.
- When `value > 1e18`, it triggers a webhook that sends a Telegram message:
“⚠️ Large transfer: 1,000 ETH from 0xA… to 0xB…”
Choosing an Alert Solution
- *Ease of Integration* – Alchemy Notify (simple REST/WebSocket), Blocknative (advanced filters).
- *Supported Chains* – Ethereum, Polygon, Solana, etc.
- *Pricing* – Free tiers for low request volumes; paid plans for high throughput.
- *Custom Logic* – Ability to filter by contract address, event signature, numeric thresholds.$BNB