Crypto Gloss

Tenderly

Definition:

Tenderly is an all-in-one Web3 developer platform that provides transaction debugging (with visual execution traces showing each EVM opcode and state change), smart contract monitoring with customizable alerts, a simulation API for testing transactions against any blockchain state, and dedicated RPC node infrastructure — helping development teams catch bugs before deployment and diagnose issues in production smart contracts faster than traditional blockchain explorers allow. Tenderly supports Ethereum, Polygon, Arbitrum, Optimism, Base, Avalanche, and most major EVM chains.

Core Features

Transaction Debugging:

Tenderly’s transaction debugger visualizes the full EVM execution trace of any on-chain transaction:

  • Function calls, internal calls, and delegate calls shown hierarchically
  • State changes (storage slots before/after) displayed per call
  • Event logs decoded with ABI context
  • Exact line of Solidity source where a revert occurred (with source mapping)
  • Gas usage at each call level

This transforms opaque hex revert data into readable debugging information — far beyond what Etherscan shows.

Transaction Simulation:

Simulate any transaction against any blockchain state without sending it:

  • Simulate as if you are any address (impersonate wallets)
  • Simulate against a specific historical block state
  • Simulate against a custom “virtual testnet” state (Tenderly Devnets)
  • Return value and state changes preview before paying gas

The simulation API is accessible programmatically, enabling agentic workflows and pre-flight checks in DApps.

Monitoring and Alerting:

Create real-time alerts for any on-chain event:

  • “Alert me if this address receives ETH”
  • “Alert if this contract function is called”
  • “Alert if this storage slot changes”
  • “Alert if gas usage exceeds X”

Webhooks, Slack, Discord, email, and PagerDuty integrations.

Virtual TestNets (Devnets):

Tenderly Virtual TestNets are isolated fork environments:

  • Fork any chain at any block
  • Persistent state between RPC calls (unlike Hardhat Network which resets)
  • Shareable environments for team testing
  • UI to inspect state and transaction history

Tenderly Web3 Gateway (RPC):

Tenderly provides reliable RPC endpoints as an alternative to Alchemy and Infura:

  • Low-latency JSON-RPC and WebSocket endpoints
  • Rate limits tailored for production use
  • Integrated with Tenderly monitoring (RPC calls visible in dashboard)

Tenderly SDK and CI/CD Integration

The Tenderly SDK enables programmatic simulation in CI pipelines:

“`typescript

const tenderly = new Tenderly({ accountName, projectName, accessKey });

const simulation = await tenderly.simulator.simulateTransaction({

network_id: “1”,

from: “0xSender”,

to: “0xContract”,

input: encodedCalldata,

value: “0”,

});

console.log(simulation.transaction.status); // “true” = success

console.log(simulation.transaction.gas_used);

“`

This enables pre-deployment testing and regression detection in GitHub Actions.

Debugger Workflow

  1. Paste a transaction hash (or import via Etherscan)
  2. Tenderly decodes the callstack: top-level call → internal calls
  3. Developer clicks any function call to see:
    Arguments passed
    Return value
    State changes during that call
    Gas consumed in that call
  4. Revert reason shown with highlighted Solidity source line

Pricing

Tenderly operates a freemium model:

  • Free: Limited simulations per month, basic monitoring, 5 contracts
  • Developer: More simulations, faster limits, TestNets
  • Teams/Enterprise: Unlimited, priority support, custom integrations

Users and Adoption

Tenderly is used by:

  • Uniswap, Aave, Compound — incident response debugging
  • Security audit firms — trace analysis for exploit investigation
  • DApp teams — pre-flight simulation before user transactions (MetaMask integration with Tenderly simulation for transaction preview)

MetaMask integrated Tenderly’s simulation API to power its transaction preview feature, giving users a preview of what their transaction will do before they sign it.

Related Terms

Sources

Last updated: 2026-04