Marketplace · API · x402

data.spencermcw.com/v1/tax/sales-rate

What is the sales tax rate at this US address, ZIP+4 or ZIP? The combined rate and each state, county, city and district rate in the 24 Streamlined Sales Tax states (WA, OH, MI, NJ, TN, …), computed by Distill from each state’s SST rate and boundary files. Refreshed quarterly (live freshness: /status). $0.005 per call (x402, USDC on Base); 3 free calls a day.

Endpoint	`https://data.spencermcw.com/v1/tax/sales-rate`
Trust	Not checked yet
Pricing	Pay per call with x402, no account. Call it to get an exact quote before paying.
network	eip155:8453
scheme	exact
pay to	0xE6900aE625875b748f56Fb45C3e06a59Be8870DF
method	GET
last updated	2026-11-11T15:13:29.84Z

Use it

Call it (an x402 client pays automatically)

curl -i https://data.spencermcw.com/v1/tax/sales-rate
# 402 reply -> sign PAYMENT-REQUIRED with an x402 client (e.g. @x402/fetch) -> retry with PAYMENT-SIGNATURE

This listing as JSON

curl https://aipaygen.com/v1/catalog/api/x402-ab206754c3b79280

Search the whole marketplace from your agent (MCP)

{
  "mcpServers": {
    "aipaygen": {
      "url": "https://aipaygen.com/mcp"
    }
  }
}