Ledgerbell
Onchain alerts for wallets, Safe multisigs and contracts: token approvals, queued Safe transactions, proxy upgrades with change reports. Free tools; Pro via USDC (x402).
Hosted MCP Server
npx add-mcp 'https://ledgerbell.quietworklabs.workers.dev/mcp'Installs into Claude Code, Codex, Cursor and more
Documentation
Know within minutes when something changes onchain.
Ledgerbell watches your wallets, Safe multisigs and contracts on Base, Ethereum, Arbitrum and OP Mainnet and posts an alert to Discord, Slack, Telegram, ntfy or any webhook. Free for 3 watches. No signup.
Use cases
After OpenZeppelin Defender
Hosted Defender Monitor is gone. Recreate the common monitors (proxy upgrades, ownership and role changes, pauses, custom events) in a minute without running your own infrastructure.
Defender monitor alternative →
Safe signer monitoring
Alert the team channel when a Safe adds or removes an owner, changes the threshold, enables a module or guard, executes a transaction, or when a new transaction is queued before anyone signs it.
Phishing approval alerts
Most wallet drains start with a signed approval. Get pinged the moment a watched wallet grants an ERC-20 approval or setApprovalForAll, and revoke it before it is used.
Proxy upgrades: what changed
When a proxy you depend on emits Upgraded, Pro sends a report comparing the old and new implementation: added/removed functions and events, changed source files, verification status.
Treasury and payment inflows
Know when USDC or any ERC-20 arrives or leaves a treasury, hot wallet or payment address. Zero-value "address poisoning" transfers are filtered out.
Custom events for bots and agents
Any contract + event signature, delivered as JSON to your webhook. Also usable by AI agents: pay for Pro with x402 and manage watches over HTTP.
What an alert looks like
⚠️ Approved 0x3f2a…91c0 to spend UNLIMITED token 0x8335…2913. If you did not mean to, revoke it.
[hot wallet] Base · block 52750911
https://basescan.org/tx/0x…
🕒 New queued Safe transaction #412 on [Treasury] Safe 0x9a1b…77e2 (Ethereum)
addOwnerWithThreshold → 0x9a1b…77e2
⚠️ changes Safe settings
Signatures 1/3 · proposed by 0x4e28…88cF
Pricing
| Free | Pro — 5 USDC / 30 days | |
|---|---|---|
| Watches | 3 | 30 |
| Alerts per day | 50 | 1,000 |
| Wallet transfers + approvals, admin events, custom events | ✓ | ✓ |
| Queued Safe transaction alerts | – | ✓ |
| Proxy-upgrade "what changed" reports | – | ✓ |
Paid in USDC on Base (any wallet or exchange withdrawal), or by AI agents via x402. Details.
FAQ
Do I need an account?
No. You get an API key (lb_…) in one click. No email, no password, no card.
Which chains?
Base, Ethereum, Arbitrum One and OP Mainnet.
How fast are alerts?
Chains are polled every 5 minutes; alerts usually arrive within about 5 minutes of the block. Queued Safe transactions are checked every ~15 minutes, or every ~5 minutes with your own Safe API key.
Is this a replacement for an audit or an incident-response team?
No. It is a notification tool. Use it alongside your other controls.