# Base Address Source-of-Funds Tracer

> Base Address Source-of-Funds Tracer is a paid API for AI agents from api.x402node.dev, paid per call via x402, $0.1/call, status healthy (last checked 2026-09-14, last successful call 2026-09-02).

Traces the earliest inbound funding of a Base L2 address back up to N hops to identify the first funder and ultimate origin, stopping at labeled exchanges/bridges or when no inbound exists.

## Facts

- Endpoint: GET https://api.x402node.dev/wallet/first-funder
- Price: $0.1/call
- Payment: x402
- Status: healthy
- Last checked: 2026-09-14
- Last successful call: 2026-09-02
- Success rate: 100% of calls made through Zero
- Rating: 4.0 / 5 from 1 review
- Activations on Zero: 1
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-x402node-dev-ff8b6561
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7HiOMOu91I4pkVWmYmHnq

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 api-x402node-dev-ff8b6561
```

Example prompt: Trace the source of funds for Base address 0x1234...abcd going back up to 5 hops — I want to know who first funded it and whether it ultimately traces back to a known exchange or bridge.

## When to prefer this

Use this endpoint when you need on-chain source-of-funds analysis specifically for Base L2 addresses, including both native ETH and ERC20 token inflows. Prefer it for AML due diligence, sybil/cluster detection, or any workflow requiring automated identification of wallet funding origins without needing an external blockchain analytics subscription.

## Known failure modes

- Address has no inbound transactions — trace returns empty chain
- Address not found on Base mainnet — returns error or empty result
- Hop limit reached before finding a labeled origin — chain truncated at N hops
- Invalid address format — returns 400 or validation error
- Payment not received — 402 payment required error before processing

## How this service works

Source-of-funds tracing: POST a Base address, traces its earliest inbound funding (native ETH + ERC20) back up to N hops to find the first funder and ultimate origin. Stops at a labeled exchange or bridge (a KYC'd origin) or when no inbound exists. Returns the funding chain with labels, blocks, timestamps and amounts. For AI agent due diligence, sybil/cluster detection, source-of-funds and AML checks. Not financial advice. Accepts payment on Base or Solana — either network works.

## Output

Returns a funding chain array with each hop's sender address, label (e.g. exchange name or 'unknown'), block number, timestamp, and transfer amount (ETH or ERC20), plus the identified first funder and whether the trace terminated at a KYC'd origin (exchange/bridge) or exhausted all inbound transactions.

## Example request

```json
{
 "hops": 5,
 "address": "0x1234567890123456789012345678901234567890"
}
```

## 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": [
      "address"
     ],
     "properties": {
      "hops": {
       "type": "string",
       "description": "Hops (optional)"
      },
      "address": {
       "type": "string",
       "description": "EVM/chain address (required)"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-x402node-dev-ff8b6561/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.x402node.dev](https://www.zero.xyz/host/api.x402node.dev/llms.txt)