Block Explorer Node

The Block Explorer node reads on-chain data directly from public block explorers. One node covers six query types — address balance, transaction details, token transfers, contract info, gas prices, and block info — across the EVM chains (Ethereum, BSC, Polygon, Arbitrum) via the Etherscan family, plus Bitcoin via Blockchain.com. Pick an explorer, a network, and a query type, and the input fields change to match. The output shape is discriminated on the query type, so downstream nodes always know what they're reading.

Why Block Explorer

Block explorers index everything that happens on a chain — every balance, transaction, contract, and block — and expose it over a free REST API. The Block Explorer node brings that into your workflows without running a node or wrangling RPC:

• Wallet monitoring — track a wallet's native balance and react when it moves.
• Transaction tracking — confirm a tx landed, check its status, and read its details.
• Contract verification — fetch a contract's verified source, ABI, and proxy implementation.
• Gas optimization — read the live gas oracle and act only when fees are low.
• Multichain on one key — the four EVM explorers share a single Etherscan key (V2 multichain API), selected by chain.

Explorers & Networks

Query Types

Configuration

Dynamic Fields

The address, transaction hash, contract address, and block number fields support the f(x) toggle. Click it to switch a field from a static value to an expression that resolves at runtime from an upstream node:

{function.walletAddress}

This lets you build workflows where the address or txid comes from an earlier node — for example, looping over a list of wallets, or checking a transaction whose hash was produced by an Exchange Order node.

Setting Up Your API Key

EVM queries run on NickAI credits by default. To run them free on your own key (and avoid sharing rate limits), connect an Etherscan API key. Bitcoin needs no key.

Step 1: Get an Etherscan API Key

1. Sign up at etherscan.io/register ↗ (free) and verify your email.
2. Go to etherscan.io/apidashboard ↗ → + Add.
3. Name the key and copy it.

The free tier allows 5 calls/sec and 100,000 calls/day — and the same key works across BSC, Polygon, and Arbitrum via the V2 multichain API.

Step 2: Add the Credential in NickAI

1. Go to Credentials in NickAI.
2. Click Add Credential and select Etherscan API.
3. Paste your API key, name it (e.g. "My Etherscan Key"), and save.

Step 3: Select in the Node

1. Open your workflow and select the Block Explorer node.
2. In the API Credential section, select your credential. Running with your own key is free.

Billing & Credits

The node runs one of two ways, chosen by the API Credential field:

• NickAI Credits (default) — runs on NickAI's Etherscan access and charges 2 NickAI credits per call.
• Your own Etherscan key — runs on your key; NickAI charges nothing for the node step.

Workflow Examples

Wallet Balance Monitor

Alert when a wallet's balance drops below a threshold.

The Block Explorer fetches the native balance, the Conditional checks {wallet.balance.formatted} against a threshold, and Telegram fires only when it's low.

Gas Price Optimizer

Run an action only when gas is cheap.

The Conditional gates on {gas.gas.fast} so the downstream action only runs when network fees are favorable.

Transaction Confirmation Watcher

Confirm a transaction landed, then notify.

Pipe a tx hash in via the f(x) toggle (e.g. from an Exchange Order node), check {tx.transaction.status}, and email on success.

Output

Every result includes the queryType discriminator and a metadata block; the data lives under a key that matches the query type.

Output by query type

Example Output

{
  "queryType": "address_balance",
  "balance": {
    "address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "raw": "5690864439481747771",
    "formatted": "5.690864439481747771",
    "symbol": "ETH",
    "decimals": 18
  },
  "metadata": {
    "source": "Etherscan",
    "explorer": "etherscan",
    "network": "mainnet",
    "requestedAt": "2026-06-24T22:58:56.844Z",
    "creditsUsed": 0
  }
}

Common Errors

Next Steps

• Conditional Node — Route on balances, gas prices, or transaction status.
• LLM Node — Summarize contract source or transaction activity with AI.
• Function Node — Parse token transfers or format raw values with custom code.
• Loop Node — Iterate over a list of wallets or transactions.
• Telegram Notification — Deliver on-chain alerts.
• Credentials — Connect your Etherscan API key.