# Base Onchain Data – ERC-20 Whale & Large-Trade Tracker

> Base Onchain Data – ERC-20 Whale & Large-Trade Tracker is a paid API for AI agents from onchaincheck.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Returns all buys and sells for an ERC-20 token on Base over the last N minutes, including USD size, side, wallet, transaction hash, buy/sell volume, net flow, and top buying/selling wallets.

## Facts

- Endpoint: GET https://onchaincheck.dev/base/trades?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-onchain-data-erc-20-whale-large-trade-tracker-72bceaf2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_UdbXuCcbhS1y2ARcPwZSS

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability base-onchain-data-erc-20-whale-large-trade-tracker-72bceaf2
```

Example prompt: Show me all whale trades over $2000 for the DEGEN token at 0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed on Base in the last 60 minutes — I want to see the top buyers, net flow, and the largest individual transactions.

## When to prefer this

Choose this endpoint when you need on-chain trade-level detail for a specific ERC-20 on Base — who is buying/selling, how large, and which wallets dominate flow — rather than just price or balance data. Ideal for whale monitoring, momentum detection, sell-pressure analysis, and pre-trade due diligence on Base tokens. Use the Arbitrum sibling endpoint for the same analysis on Arbitrum One.

## Known failure modes

- Missing or invalid token address returns a validation error
- minutes outside 5-240 range may be rejected or capped
- token with no liquidity on tracked pools returns empty trade arrays
- limit value outside 1-40 range rejected by pattern validation
- minUsd set very high may return no trades even if activity exists
- network issues or RPC timeouts may produce 5xx errors
- very recent blocks may not yet be indexed

## How this service works

Whale and large-trade tracker for an ERC-20 on Base: every buy and sell in the last N minutes on the token's deepest WETH/USDC pools (Uniswap v3 or Aerodrome), with USD size, side, wallet and transaction for the largest trades, buy/sell volume and net flow, and the wallets that bought or sold the most.

## Output

A JSON object with: chain identifier, token metadata (symbol, address, decimals), the query window (from/to timestamps and block range), a summary (buy/sell counts, total trades, buy/sell volume in USD, net flow, largest trade), ETH/USD price used for conversions, an ordered list of top buyers (wallet, trades, bought/sold/net USD), an ordered list of top sellers, and an array of large individual trades (tx hash, DEX, USD size, buy/sell side, block number, wallet, approximate timestamp, quote and token amounts). Covers the 3 deepest WETH/USDC pools on Uniswap v3 or Aerodrome.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "token"
     ],
     "properties": {
      "limit": {
       "type": "string",
       "pattern": "^\\d{1,2}$",
       "description": "Max trades listed, 1 to 40, default 20"
      },
      "token": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "Token contract address on Base"
      },
      "minUsd": {
       "type": "string",
       "pattern": "^\\d+(\\.\\d+)?$",
       "description": "Only list trades at least this large in USD, default 1000"
      },
      "minutes": {
       "type": "string",
       "pattern": "^\\d{1,3}$",
       "description": "Look-back window in minutes; 5 to 240, default 60 (capped at 12,000 blocks, about 50 minutes on Arbitrum)"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "chain": "base",
  "notes": "Trades from the 3 deepest WETH/USDC pools; other pairs and aggregator-internal routes are not counted. Wallets are transaction senders, looked up for the 40 largest trades.",
  "token": {
   "symbol": "DEGEN",
   "address": "0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed",
   "decimals": 18
  },
  "window": {
   "to": "2026-10-22T16:22:57.000Z",
   "from": "2026-10-22T15:22:57.000Z",
   "minutes": 60,
   "toBlock": 52948415,
   "fromBlock": 52946615
  },
  "summary": {
   "buys": 20,
   "sells": 1,
   "trades": 21,
   "netFlowUsd": 1223.35,
   "buyVolumeUsd": 1223.4,
   "sellVolumeUsd": 0.0558468,
   "largestTradeUsd": 142.466
  },
  "nativeUsd": 2396.4,
  "topBuyers": [
   {
    "netUsd": 471.2,
    "trades": 9,
    "wallet": "0x3dA47e29a82651171c57956A73F80b3905B8b230",
    "soldUsd": 0,
    "boughtUsd": 471.2
   },
   {
    "netUsd": 262.4,
    "trades": 2,
    "wallet": "0x2342110f3Af09c848C104fdE3E7261Dc0C5C4d7a",
    "soldUsd": 0,
    "boughtUsd": 262.4
   },
   {
    "netUsd": 239.6,
    "trades": 2,
    "wallet": "0x9CA5CAcb8CD8820415f7cA3C3C3cf7E23c885bd7",
    "soldUsd": 0,
    "boughtUsd": 239.6
   },
   {
    "netUsd": 142.3,
    "trades": 1,
    "wallet": "0x2c2e035D20Cd6da1664a7Cf0EAf98e3647607304",
    "soldUsd": 0,
    "boughtUsd": 142.3
   },
   {
    "netUsd": 67.59,
    "trades": 1,
    "wallet": "0x911E228d9105963b68af40880Ce8Dd6d5Ee8637E",
    "soldUsd": 0,
    "boughtUsd": 67.59
   }
  ],
  "topSellers": [
   {
    "netUsd": -0.05585,
    "trades": 1,
    "wallet": "0xbdBeBD58cC8153Ce74530BB342427579315915B2",
    "soldUsd": 0.05585,
    "boughtUsd": 0
   }
  ],
  "largeTrades": [
   {
    "tx": "0x2079d9a6e334ecfb885c7f0144002d59e1c9030f4e34cf9f4a54968d91f11e4f",
    "dex": "uniswap-v3",
    "usd": 142.466,
    "side": "buy",
    "block": 52946817,
    "wallet": "0x2342110f3Af09c848C104fdE3E7261Dc0C5C4d7a",
    "approxTime": "2026-10-22T15:29:41.000Z",
    "quoteAmount": 0.05945,
    "quoteSymbol": "WETH",
    "tokenAmount": 149873.49
   },
   {
    "tx": "0x63e5e82b77986e25689e4e68c61044c15c8f5431038b1bfdaf72aa499401464b",
    "dex": "uniswap-v3",
    "usd": 142.322,
    "side": "buy",
    "block": 52947027,
    "wallet": "0x2c2e035D20Cd6da1664a7Cf0EAf98e3647607304",
    "approxTime": "2026-10-22T15:36:41.000Z",
    "quoteAmount": 0.05939,
    "quoteSymbol": "WETH",
    "tokenAmount": 149535.86
   },
   {
    "tx": "0x8b75da4612b49b617aa6f50ab419bbd80586557811e194b4ef74cc72
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-onchain-data-erc-20-whale-large-trade-tracker-72bceaf2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from onchaincheck.dev](https://www.zero.xyz/host/onchaincheck.dev/llms.txt)