Best Smart Contract Monitoring Tools in 2026

Updated November 2026 6 min read

Quick answer. The best smart contract monitoring tools in 2026, ranked:

Guardian Managed Security
Hypernative
Hexagate (Chainalysis)
BlockSec Phalcon
Cyvers
Tenderly
OpenZeppelin Monitor
Forta
Blockaid

Watch: Best Smart Contract Monitoring Tools in 2026 1:40

Video transcript

Smart contract monitoring tools now compete on response, not just alerts. We ranked nine platforms, and the real question is who acts when an alert fires.

Disclosure: Guardian publishes this guide and ranked its own service first. The category has also changed. Chainalysis bought Hexagate, and OpenZeppelin shut down hosted Defender in July 2026.

Guardian Managed Security puts an engineer on every alert. Hypernative automates onchain response across many chains. Hexagate offers programmable detection, Phalcon blocks attacks automatically, and Cyvers adds AML screening.

Then Tenderly for engineering teams, OpenZeppelin Monitor for self-hosted control, Forta for dependency risk, and Blockaid for wallets at the moment of signing.

Tools detect, and most can automate actions. But who reads the alert at three AM, and who holds the key to pause? Managed detection and response adds people, an SLA and agreed authority.

Guardian responds to every alert, onchain and offchain, with a fifteen minute SLA on Critical alerts.

To choose, inventory every contract and privileged role. Define your detections. Decide which responses run automatically. Test on a fork with a past exploit. And cover offchain too.

Most teams holding real value run both a detection platform and a team that acts on it. Read the full ranking, or talk to Guardian about putting a response team behind your monitors.

Disclosure: Guardian publishes this guide, and we ranked our own service first. Claims about other vendors come from their own sites or reputable reporting, linked in our sources at the end.

Smart contract monitoring tools watch deployed contracts and the transactions around them. They alert or act when something matches a rule or looks like an attack.

The category has changed. Chainalysis bought Hexagate in December 2024, and OpenZeppelin shut down hosted Defender on July 1, 2026.

The leading platforms now compete on automated response, not just alerts. This guide ranks nine tools on what they detect, how they respond and who acts.

How We Evaluated

Detection: contract calls and events, the mempool, offchain surfaces, and chains supported.
Response: alerts only, or automated actions such as pausing a contract or blocking a transaction.
Who acts: your own team, or people who triage and respond for you.
Deployment and control: SaaS, self-hosted or managed, and which privileges automated responses need.
Fit: protocols, institutions, wallets or chains.

Comparison at a Glance

#	Tool	Type	Response	Best for
1	Guardian Managed Security	Managed service with a 24/7 MDR team	An engineer on every alert; custom actions including automated pauses	Teams that want people, not just alerts
2	Hypernative	SaaS platform plus services	Automated onchain response, including pauses	Enterprises and protocols across many chains
3	Hexagate (Chainalysis)	SaaS	Contract pauses, transaction blocking, playbooks	Programmable detection and pre-signing checks
4	BlockSec Phalcon	SaaS	Automated blocking transactions that front-run attacks; pauses	Automatic attack blocking
5	Cyvers	SaaS and API	Pause contracts, block transactions, trigger playbooks	Institutions wanting monitoring plus AML screening
6	Tenderly	Developer platform	Web3 Actions	Engineering teams
7	OpenZeppelin Monitor	Open source, self-hosted	Notifications; responses through OpenZeppelin Relayer	Full control, no vendor in the loop
8	Forta	Risk platform and sequencer firewall	Firewall stops screened transactions before execution	Dependency risk; chains
9	Blockaid	Transaction security platform	Blocks malicious transactions at signing; programmatic responses	Wallets and consumer apps

The 9 Best Smart Contract Monitoring Tools

1. Guardian Managed Security

Model: managed security service with a global 24/7 MDR team
Watches: contracts on every block; domains, DNS, certificates, cloud and code host offchain
Response: an engineer on every alert, with a 15-minute SLA on Critical alerts

Guardian ranks first because monitoring is only half the job.

Managed Security watches privileged calls, role changes, upgrades, multisig transactions and large fund movements, with monitors customized to your protocol.

When something fires, a Guardian engineer responds. Your existing monitoring can stream into the same MDR team.

Guardian says Managed Security runs on least privilege and is read-only, with monitoring built on public chain state.

2. Hypernative

Model: SaaS platform plus security services, including expert incident response
Watches: 300+ risk types across 70+ chains, by its own account
Response: automated onchain response, including automatic contract pauses

Hypernative positions itself as "Proactive Onchain Security for Enterprises", selling to institutions, chains, DeFi protocols, exchanges and custodians.

In October 2025, Hypernative and Cantina announced a partnership: Hypernative handles detection, and Cantina handles response.

3. Hexagate (Chainalysis)

Model: SaaS, sold by Chainalysis since it acquired Hexagate in December 2024
Watches: key compromises, exploits, phishing, governance attacks and anomalous token flows, on 75+ chains
Response: contract pauses and transaction blocking, with alerts to Slack, Telegram, email and SIEM tools

Gatelang, Hexagate's custom detection language, lets teams write their own monitors. GateSigner simulates and analyzes transactions before they are signed, and works with Safe wallets.

4. BlockSec Phalcon

Model: SaaS from BlockSec
Watches: mempool transactions, checked against over 200 typical hacking characteristics
Response: automatic blocking transactions that front-run the malicious one through gas bidding; automatic pauses for L2 protocols

Phalcon is explicit that someone needs authority to act. It offers three modes: Pre-Signed Transaction, Delegation of privileges such as pausing, and Multi-Sig with Delegation.

5. Cyvers

Model: SaaS, with a dashboard, REST API, webhooks and SDKs
Watches: "Real-time smart contract & wallet monitoring across chains"
Response: pause contracts, block transactions and trigger playbooks

Cyvers pairs monitoring with a Pre-Transaction Firewall that simulates each transaction before signing. It integrates with Safe, Fireblocks and major MPC providers.

Its Compliance and Risk product covers AML counterparty screening, and it lists SOC 2 Type II.

6. Tenderly

Model: developer platform: Simulator, Console, Monitor and Node
Watches: alerts and invariants you define, on 100+ supported networks
Response: Web3 Actions, custom responses that can "top up accounts, pause execution"

Monitoring sits inside the developer workflow. The team that writes an alert can simulate the fix, inspect the failing transaction and ship the response.

7. OpenZeppelin Monitor

Model: open source (AGPL-3.0, Rust), self-hosted or hosted by OpenZeppelin's Managed Service
Watches: functions, events and transaction properties you specify, on EVM networks, Stellar and Solana
Response: Slack, Discord, email, Telegram, webhooks and scripts; automated responses through Relayer

It succeeds Defender's monitoring module; our guide to OpenZeppelin Defender alternatives covers the migration.

Detection is the rules you write, not prebuilt attack detection. You also run the service, its RPC endpoints and its storage.

8. Forta

Model: Forta Risk and Forta Firewall, beside the Forta Monitoring Network of detection bots
Watches: every dependency behind your assets, "mapped, quantified in USD and monitored block by block"
Response: Forta Firewall screens transactions at the sequencer and stops undesired activity

Forta's homepage now leads with Forta Risk and Forta Firewall. Its documentation still describes the Monitoring Network and how to run detection bots.

9. Blockaid

Model: transaction security platform for wallets, dApps, DeFi and institutions
Watches: transactions, addresses, tokens and dApps
Response: stops scams, drainers and hacks before they reach users

Blockaid centers on the moment of signing, with End User Protection for wallets and dApps, a Cosigner for wallet operations, and Onchain Monitoring for DeFi teams.

Tools vs Managed MDR

Every tool above produces detections, and most can run automated actions. None of them, on its own, answers the questions that decide an incident:

Who reads the alert at 3 AM, and how quickly?
Who has authority to pause, and through which key?
Who handles a false positive that paused your protocol?
Who investigates afterwards, and who covers the domain, frontend and cloud?

Managed detection and response adds people, an SLA and agreed response authority on top of detection.

Most teams that hold real value run both: a detection platform and a team that acts on it, in-house or managed.

We explain the category in What Is Web3 MDR?, and why minutes matter in our look at how fast crypto hacks are detected.

How to Choose

Inventory first: every contract, chain, privileged role and multisig you need watched.
Define the detections: role changes, upgrades, parameter changes, large outflows, oracle deviations, exploit contracts.
Decide the response: which actions run automatically, which need a human, and what privilege each needs.
Test on a fork: replay a past exploit pattern and confirm detection and response both work.
Cover offchain: onchain tools miss a hijacked domain or leaked cloud key until it reaches the chain.
Keep rules portable: keep detection logic in version control. Defender's shutdown showed why.

Where Guardian Fits

Guardian's Managed Security is the response layer: an MDR team on every alert, onchain and offchain, with a 15-minute SLA on Critical alerts.

For configuration drift and external exposure, Guardian's Risk Monitoring tracks deployed contracts, privileged roles and internet-facing hosts. An engineer confirms each finding.

Frequently Asked Questions

What are the best smart contract monitoring tools in 2026?

Against this guide's criteria, Guardian Managed Security ranks first, followed by Hypernative, Hexagate (Chainalysis), BlockSec Phalcon, Cyvers, Tenderly, OpenZeppelin Monitor, Forta and Blockaid. Guardian publishes this guide, so weigh the ranking accordingly.

Can monitoring tools stop an exploit automatically?

Hypernative, Hexagate, Cyvers and BlockSec Phalcon say they can, by pausing contracts or blocking transactions. Those actions need privileges you grant, such as a pauser role or pre-signed transactions, so test them and decide who holds them.

Do I need offchain monitoring as well?

Yes, if users reach you through a website or you run on cloud accounts, keys and DNS. Onchain tools miss a hijacked domain, changed frontend or leaked cloud credential until it shows up onchain.

Sources

Put a response team behind your monitors

Guardian Managed Security puts an engineer on every alert, onchain and offchain, with a 15-minute SLA on Critical alerts.

Talk to Guardian Explore Managed Security