Modular Monitoring with Web3Actions - Tenderly

This guide demonstrates how to build a flexible monitoring system that can track any on-chain event, process transaction data, and deliver real-time notifications through webhooks. By combining powerful trigger criterias of Tenderly’s Alert system with Web3Actions, you’ll create a modular monitoring infrastructure that can adapt to any blockchain monitoring need, from simple event tracking to complex multi-contract interactions.

This guide assumes you have a Tenderly account and basic familiarity with Web3Actions and blockchain events.

Modular Monitoring with Web3Actions

Prerequisites

Before starting, ensure you have:

Node.js (v20 currently supported as latest version)
Tenderly CLI installed
A webhook endpoint for receiving data
Basic understanding of TypeScript

System Setup

Core Components

Transaction Processing

The system begins by processing transaction information:

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export const modularFn = async (context: Context, transactionEvent: TransactionEvent) => {
  const txHash = transactionEvent.hash;
  const txNetwork = transactionEvent.network;

  const blockHash = transactionEvent.blockHash;
  const blockNumber = transactionEvent.blockNumber;

  const WEBHOOK_URL = await context.secrets.get("WEBHOOK_URL");
  const BEARER = await context.secrets.get("BEARER");
  const ACCOUNT_SLUG = await context.secrets.get("ACCOUNT_SLUG");
  const PROJECT_SLUG = await context.secrets.get("PROJECT_SLUG");
  const EVENT_NAME = await context.secrets.get("EVENT_NAME");

  if (!EVENT_NAME) {
    throw new Error("EVENT_NAME not found in environment variables");
  }

  const url = `https://api.tenderly.co/api/v1/public-contract/${txNetwork}/trace/${txHash}`;

  const traceResponse = await axios.get(url, {
    headers: {
      authorization: BEARER,
    },
  });

  const traceData = traceResponse.data;

This component:

Captures transaction hash and network
Retrieves transaction traces via Tenderly API
Processes block information

Contract Information Retrieval

Contract information (names and ABIs) are fetched using the Contracts API.

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const fetchContractName = async (addr: string) => {
  const contractEndpoint = `https://api.tenderly.co/api/v1/account/${ACCOUNT_SLUG}/project/${PROJECT_SLUG}/contract/${txNetwork}/${addr}`;

  try {
    const contractResponse = await axios.get(contractEndpoint, {headers: {'Authorization': BEARER}});
    return contractResponse.data.contract.contract_name;
  } catch (error) {
    console.error(`Error fetching contract name from endpoint for ${addr}:`, error);
  }
};

const fetchContractAbi = async (addr: string) => {
  const contractEndpoint = `https://api.tenderly.co/api/v1/account/${ACCOUNT_SLUG}/project/${PROJECT_SLUG}/contract/${txNetwork}/${addr}`;

  try {
    const contractResponse = await axios.get(contractEndpoint, {headers: {'Authorization': BEARER}});
    return contractResponse.data.contract.data.abi;
  } catch (error) {
    console.error(`Error fetching contract ABI from endpoint for ${addr}:`, error);
  }
};

Event Processing

Event processing is handled through specialized functions:

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const extractEventAddresses = (logs: any[]): string[] =>
  Array.from(new Set(
    logs
      .filter(log => log.name === EVENT_NAME)
      .map(log => log.raw.address)
  ));

const extractEventDetails = (logs: any[]) => {
  return logs
    .filter(log => log.name === EVENT_NAME)
    .map(log => {
      const result: { [key: string]: string } = {
        name: log.name
      };

    log.inputs.forEach((input: any) => {
      const name = input.soltype.name;
      const value = input.value.toString();
      result[name] = value;
    });

    return result;
  });
};

This section:

Filters events by name
Extracts event parameters
Processes event addresses

Webhook interaction

The system sends this structured data to your webhook using Axios:

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{
  hash: string,              // Transaction hash
  transaction: object,       // Full transaction event
  blockHash: string,        // Block hash
  blockNumber: number,      // Block number
  matchReasons: Array<{     // Event details
    name: string,
    [parameterName: string]: string
  }>,
  sentinel: {               // Contract information
    contractName: string,
    abi: object
  },
  traceData: object,        // Transaction trace data
  addresses: string[]       // Involved addresses
}

Troubleshooting

Common issues and solutions:

Missing Events
- Verify EVENT_NAME matches contract events exactly
- Check alert configuration in Tenderly dashboard
- Review transaction logs for event emission
API Errors
- Validate BEARER token permissions
- Check API endpoint availability
- Verify network configuration
Webhook Issues
- Confirm WEBHOOK_URL accessibility
- Check payload format matches expectations
- Monitor webhook endpoint logs

Lido Validator Exit Notifications Node RPC Access

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