How to replace OpenZeppelin Defender Monitor alerts

What Defender Monitor did

• Custom filters: your own code received the matches for a block and decided which ones counted.
• Confirmation blocks: how many blocks to wait before notifying, to trade speed for safety against reorganisations.
• An alert threshold and a minimum time between notifications, to cap repeated alerts.
• Notification channels from chat apps to incident tools and custom APIs, Telegram among them, with an editable message template.
• Actions and Workflows that ran when a match happened, for an automated on-chain response.
• Templates for common cases, five risk categories and a severity level for grouping.

The shutdown and OpenZeppelin Monitor

What a contract rule covers

• Event emitted: one event from the standard catalog, one of the events listed for a well-known contract, a pasted event signature, or every event the contract emits.
• Method called: one function, by pasting its signature or 4-byte selector, or any method, with a choice of succeeded, failed or either.
• Argument conditions by name: is, is not, is one of, greater than, at least, contains and similar, depending on the argument's type; [] means any element of an array.
• Transaction conditions: Caller (tx.from) is, or is not, one of a list of addresses, and the ETH value sent.
• Delivery: one Telegram message per transaction per rule, to a chat or a group, within seconds of the transaction being confirmed.

• Smart contract event alerts
• Smart contract function call alerts
• Safe multisig alerts

What it doesn't do

• Ethereum mainnet only. More networks are planned, but none is live yet.
• Telegram is the only live channel. Discord, Slack, email and webhooks are coming.
• Alerts arrive within seconds of the transaction being confirmed. Pending (mempool) transactions are not alerted.
• No custom filter code and no OR or NOT expressions: all the conditions on a rule must match. Use one rule per alternative.
• No conditions on gas, nonce or the transaction's to field; only Caller and ETH value.
• No automated actions or relaying. Alerts on Chain is read-only: it never signs or sends a transaction in response to a match.
• No alert threshold, quiet period or confirmation-depth setting, and no editable message template: every alert uses the same format.
• Method calls are direct calls only. Calls made through Safes, routers or multicall are coming with Premium; events are emitted either way.
• No USD values; amounts are raw token units unless you set the token's decimals.

Map a Defender Monitor setup onto rules

• Contracts: each contract is its own watched address. If one Defender Monitor covered several contracts with the same ABI, add each address and give it the same rules.
• Events: one rule per selected event, since several events were an OR. To keep everything a contract emits, use one rule on every event.
• Functions: one Method called rule per selected function. Paste the function signature with parameter names, so conditions can refer to them.
• Event and function conditions: name the argument instead of its position. Terms joined with and become several conditions on one rule; terms joined with or become separate rules.
• Transaction filter: from becomes a Caller condition, value an ETH value condition, and status the method rule's succeeded or failed choice. Gas fields have no equivalent.
• Notifications: connect each Telegram chat or group on the Channels tab, then pick it on the rule.
• Custom filters, Actions, Workflows and thresholds: no equivalent. Keep them in your own code, or use OpenZeppelin Monitor for that part.

Set it up step by step

From sign-in to your first alert, in the actual dashboard.

1. 1
   Sign in at alertsonchain.com with Google or with your wallet. A wallet sign-in is a signed message, not a transaction, so it costs no gas.
2. 2
   Open the Channels tab and connect Telegram: start a chat with @alertsonchain_com_bot, send /start, and paste the 8-character code it replies with.
3. 3
   Open the Everything on a contract template and paste the contract address from your Defender Monitor setup. Use the proxy address for upgradeable contracts.
4. 4
   Open the rule and choose the event from the catalog, or paste the event or method signature. Add one rule per event or function you had selected.
5. 5
   Add the argument conditions, then Caller or ETH value conditions in place of the transaction filter, and pick the Telegram chat the rule sends to.
6. Click Create rule. The rule is active straight away, and the next matching transaction sends a Telegram message.