March 2026 — 0agent

OpenZeppelin confirmed it: Defender sunsets July 1, 2026.

If you use Defender's wallet monitoring or alerting features, you have roughly four months to find a replacement. This post explains what 0watch is, why we built it the way we did, and how to get your first wallet monitored in under five minutes — no account required.

What 0watch does

0watch monitors on-chain wallet activity and delivers alerts through whatever channel your team actually uses: email, Slack, Telegram, PagerDuty, or HTTP webhooks.

The key distinction: 0watch classifies transactions before alerting. When a wallet moves funds, you don't get raw calldata — you get a structured event that tells you what actually happened. ETH transfer. ERC-20 approval. Uniswap swap. Large transfer anomaly. 0watch decodes the action first, then fires the alert.

That matters in practice. An alert that says "transaction detected on 0x..." requires you to go look it up. An alert that says "large_transfer — 52 ETH outbound — severity: high" tells you immediately whether you need to wake someone up.

Current coverage: Ethereum, Base, Arbitrum, Optimism.

Who this is for

Three types of teams have the most to gain right now:

DeFi protocol teams replacing OZ Defender. If you're running keeper bots, relayers, or treasury multisigs and you've been using Defender for monitoring and alerting — 0watch handles that workload. One API call to register a wallet. Alerts start flowing immediately.

AI agent operators. The tools that monitor wallets were all built before autonomous agents existed. They were designed for developers debugging contracts or analysts watching whale wallets — not for teams operating fleets of smart wallets executing live transactions. 0watch is the first product designed around the actual operational pattern: an agent acts, something deviates from expected behavior, someone gets paged.

Teams evaluating "build vs. buy." The two most common raw-webhook alternatives (Alchemy Notify, QuickNode Streams) deliver events but no notification stack. You still have to build the email/Slack/PagerDuty routing yourself. That's 2–5 days of engineering time to reach feature parity with 0watch's $49/mo Developer tier. The math on build vs. buy is straightforward.

How to get started

No account required for the first request.

Add a wallet and get your API key in one call:

curl -X POST https://watch.0agent.ai/api/auth/signup \
  -H 'Content-Type: application/json' \
  -d '{
    "email": "[email protected]",
    "password": "YourPassword123",
    "first_wallet": "0xYourWalletAddress",
    "wallet_label": "keeper-bot-1"
  }'

Response includes your API key (owk_...) and confirms monitoring is active.

Register a webhook alert on that wallet:

curl -X POST https://watch.0agent.ai/api/webhooks \
  -H "Content-Type: application/json" \
  -H "X-API-Key: $API_KEY" \
  -d '{
    "url": "https://your-endpoint.example.com/hook",
    "wallet_address": "0xYourWalletAddress",
    "threshold_eth": 0.1
  }'

When any transaction on that wallet exceeds 0.1 ETH, 0watch POSTs a signed JSON payload to your endpoint. HMAC signature verification is included — no need to trust the source blindly.

That's the setup. Two API calls. Under five minutes from zero to live alerts.

Why crypto-native billing matters

Every DeFi team we've talked to has the same friction with developer tooling: you ship on-chain, but your SaaS subscriptions still run through Stripe and credit card approvals. The billing stack doesn't match where your treasury actually sits.

0watch accepts USDC on Base. No Stripe, no card, no billing form. Pay from the wallet your team already uses for on-chain operations.

Pricing

Tier Price Wallets Alert channels History
Free $0 3 Email 7 days
Developer $49/mo 10 Email, Slack, Webhook 90 days
Team $199/mo 50 + PagerDuty, all channels 1 year
Enterprise Custom Unlimited Custom SLA Unlimited

Free tier is unrestricted time-wise — useful for evaluation and low-volume monitoring. Developer tier ($49/mo) covers most team use cases: 10 wallets, sub-5-minute alert latency, full notification stack.

For teams coming from OZ Defender: we're offering a 3-month free trial on the Developer tier for Defender migrants before July 1. Reply to this post or email [email protected] to claim it.

The migration path from OZ Defender

The Defender wallet monitoring workflow maps cleanly to 0watch:

Defender 0watch equivalent
Defender Sentinels (wallet monitor) POST /api/wallets
Notification channels (Slack, email) Configured per-account at signup
Webhook notifications POST /api/webhooks
Alert history GET /api/wallets/{address}/alerts

What Defender had that 0watch doesn't: smart contract event monitoring (function calls, event emissions). If that's your primary use case, Tenderly is the right replacement. 0watch is the right replacement if your monitoring is wallet-address-level — watching what moves where, not what a contract does internally.

Get started

Base URL: https://watch.0agent.ai

Quickstart: watch.0agent.ai/docs/0watch-quickstart

API reference: watch.0agent.ai/docs/0watch-api-reference

For questions or migration help: [email protected]

The July 1 deadline is real. Four months goes fast when you're shipping other things. The setup takes five minutes — might as well do it now.