Sentinel is the drop-in replacement for your Defender monitoring
Same event types. Same alert channels. No Autotask code to rewrite, no infrastructure to maintain. Set up in under 5 minutes and your monitoring goes live immediately.
How Sentinel stacks up against Defender
Everything you need to evaluate whether Sentinel covers your monitoring needs — and what it doesn't (yet).
| Capability | Sentinel | OpenZeppelin Defender |
|---|---|---|
| Contract monitoring (eth_getLogs) | ✓ Yes 24/7 polling on ETH, Arbitrum, Base, Polygon | ✓ Yes Sentry monitors — but infrastructure going away |
| Alert delivery (webhook / Slack) | ✓ Yes Native endpoint — no Autotask code required | ✓ Yes Autotask webhooks — requires JS/TS code |
| Email alerts | ✓ Yes | ✓ Yes SMTP relay via Defender |
| Dashboard & alert history | ✓ Yes Dedicated monitoring dashboard + alert log | ✓ Yes Defender web UI — going offline July 2026 |
| Transfer event monitoring | ✓ Yes Configurable threshold (flag large transfers) | Partial Custom ABI required |
| OwnershipTransferred monitoring | ✓ Yes | Partial Custom ABI required |
| Pause/Unpause event monitoring | ✓ Yes | Partial Custom ABI required |
| Threshold-based alerting (amount gates) | ✓ Yes Per-contract, per-event threshold config | Partial Conditional logic in Autotask code |
| Multi-chain support | ✓ Yes Ethereum, Arbitrum, Base, Polygon | ✓ Yes Multi-network via separate contracts |
| Setup complexity | ✓ Low Paste contract address → select events → add webhook URL. Done. | Medium Sentry + Autotask + Relay + code |
| No self-hosting required | ✓ Yes | ✓ Yes |
| Price | ✓ From $29/mo Starter: 3 contracts · Pro: unlimited | ✗ Deprecated Was paid; now shutting down |
Data accurate as of June 2026. OpenZeppelin Defender final shutdown: July 1, 2026.
What Sentinel does out of the box
Defender required Autotask code for logic that Sentinel handles natively. Paste a contract address, set your thresholds, point your webhook — done.
Large transfer detection
Set a Wei threshold per contract. Sentinel flags any Transfer event above your threshold — no code, no Autotask.
Ownership change alerts
Monitoring OwnershipTransferred events across all your contracts. Immediate alert when admin keys change.
Pause/Unpause monitoring
Flag Paused and Unpaused events — critical for protocols where the pause role is a security control.
Webhook + email delivery
Alerts go to your Slack channel, Discord webhook, or inbox. No Autotask code, no relay infrastructure to maintain.
Alert history & audit log
Every alert logged with timestamp, event type, and payload. Useful for incident post-mortems and compliance records.
Synthetic test alerts
Fire a test alert to your webhook or email on demand. Validate your delivery path before going live.
From Defender to Sentinel in 3 steps
No downtime. No code changes. Just point your monitoring at Sentinel and decommission Defender when you're ready.
Export your Defender contracts
OpenZeppelin hasn't disabled the UI yet — pull your contract addresses and networks from Defender now, while it's still accessible. Do this before July 1, 2026.
Add them to Sentinel
Paste each contract address, pick your network, set event types and thresholds, point your Slack webhook URL or email. Takes about 2 minutes per contract. Start with the free Starter plan — 3 contracts included.
Validate and cut over
Use Sentinel's test alert to confirm your webhook receives events correctly. Run parallel monitoring for 24 hours if you want. Then disable your Defender Sentry monitors — your monitoring is already live on Sentinel.
What Sentinel doesn't do (yet)
No point pretending it's a perfect fit for everything. Sentinel focuses on event monitoring and alert delivery. Here's what it intentionally leaves out:
Automated transaction relay
Sentinel monitors and alerts — it doesn't send transactions or execute on-chain actions. For multisig keepers and gas-optimized relay, you need a dedicated execution layer (e.g., Gnosis Safe + keeper).
Gas optimization
Defender's relay had built-in gas logic for transaction execution. Sentinel doesn't touch gas — it watches events and delivers alerts.
Contract verification / ABI import
Sentinel lets you configure event types and thresholds manually. Etherscan-based ABI auto-import isn't built in yet — you configure events directly.
If you used Defender mainly for monitoring + alerting: Sentinel is the right drop-in replacement. If you depended heavily on Autotask execution for transaction relay or on-chain automation, you'll need to solve that piece separately — Sentinel handles the monitoring layer, not the execution layer.
Your monitoring doesn't have to go dark
Start with the free Starter plan. Add your contracts, validate your alerts, then scale up when you're ready.
No credit card required to start · Cancel anytime · Secure Stripe checkout