Goodsong

Goodsong is an x402-native service at https://goodsong.dev, indexed from the x402 Bazaar (Coinbase's public discovery directory). It charges callers itself in USDC on Base and is paid directly at its own wallet; Monex Protocol passes your request and payment headers through untouched. 6 endpoints listed.

Base

Offers

Offer	Endpoint	Price
Verify Case Verify a legal case citation: does it exist, and does the given case name match the canonical record? Catches a fabricated case citation, including a real-looking citation number paired with an invented case name. Checked against CourtListener. Does not check whether a case is still good law -- no free authoritative source publishes that.	`/m/bz-goodsong-dev/verify/case`	0.01 USDC
Verify Citation Verify a citation: does it exist, is it retracted, and do the given title/authors/year/journal match the canonical record? Checked against Crossref (retraction data included) with OpenAlex as a fallback when no DOI is given.	`/m/bz-goodsong-dev/verify/citation`	0.005 USDC
Verify Package Verify a package: does it exist, is it deprecated or yanked, and does it have known vulnerabilities? Checked against the npm/PyPI/crates.io registry plus OSV.dev advisories.	`/m/bz-goodsong-dev/verify/package`	0.005 USDC
Verify Repo Verify a GitHub repo: does it exist, is it archived or disabled? Catches an agent recommending or depending on a repo that's been renamed, taken down, or abandoned. Checked against the GitHub REST API.	`/m/bz-goodsong-dev/verify/repo`	0.005 USDC
Verify Seller Verify an x402 seller before paying it: does it exist and respond with a well-formed 402 challenge, is its own declared input/output schema internally consistent, and is its payout address sanctioned? Checked live against the seller itself plus Chainalysis's sanctions oracle and Blockscout (Base payTo addresses only). Confirms the checkable things about a seller check out -- not a guarantee of tru	`/m/bz-goodsong-dev/verify/seller`	0.005 USDC
Verify Url Verify a URL: does it resolve, what's the final status and redirect chain, is it archived on the Wayback Machine, and (optionally) does expected text appear on the page. Checked via direct fetch and the Internet Archive.	`/m/bz-goodsong-dev/verify/url`	0.005 USDC

Machine-readable: openapi.json with x-payment-info offers.

Try it live

Run the full MPP flow from your browser: catch the 402, sign the payment with your wallet, and watch it settle on-chain.

This merchant settles over the mppx rail; pay it from an agent with the snippet below.

Pay with an agent

Any MPP or x402-compatible client works. With mppx, payment is automatic:

import { Mppx, evm } from 'mppx/client'
import { privateKeyToAccount } from 'viem/accounts'

const mppx = Mppx.create({
  methods: [evm({
    account: privateKeyToAccount(process.env.KEY),
    currencies: [evm.assets.base.USDC],
  })],
})

const res = await mppx.fetch('https://api.meshgateway.co/m/bz-goodsong-dev/verify/case')
// 402 challenge signed and settled automatically; response includes Payment-Receipt

Or inspect the challenge yourself:

curl -i https://api.meshgateway.co/m/bz-goodsong-dev/verify/case
# HTTP/1.1 402 Payment Required
# WWW-Authenticate: Payment id="…", method="evm", intent="charge", …