x402basequality 0.30

US 2021 tax return data via x402 micropayment on Base for $0.02 per request.

Price
0.02 USDC / call
Protocol
x402
Verified
no
Endpoint
https://lowpaymentfee.com/api/v1/tax/returns/2021

What it does

This endpoint at lowpaymentfee.com provides access to US tax return data for the 2021 tax year. It is part of a broader platform offering dozens of pay-per-call API endpoints spanning data analytics, AI/ML inference, finance, crypto, and utility services — all gated behind the x402 payment protocol on the Base network.

The specific endpoint `/api/v1/tax/returns/2021` accepts POST requests and returns JSON. Payment is settled in USDC (USD Coin) on Base. The x402 challenge advertises a maxAmountRequired of 20,000 base units, which at 6 decimals for USDC equals $0.02 per request — consistent with the platform's uniform $0.02/request pricing. No API keys are required; access is granted per-call via the X-PAYMENT header. The platform advertises no rate limits and instant access.

Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what fields the tax return data contains or what input parameters the POST body expects. The endpoint is confirmed live (returns a proper 402 challenge), but the actual data content and request format must be discovered by the caller.

Capabilities

x402-paymentusdc-settlementbase-networktax-datajson-apipay-per-callno-api-key

Use cases

  • —Retrieving US 2021 tax return data programmatically
  • —Integrating tax data into financial analysis workflows
  • —Agent-driven tax document lookups with micropayments

Fit

Best for

  • —Developers needing on-demand tax return data without subscription commitments
  • —AI agents that can pay per-call via x402 on Base
  • —Applications requiring 2021 US tax year information

Not for

  • —Users who need comprehensive multi-year tax data (only 2021 is confirmed at this path)
  • —Anyone requiring detailed API documentation or schema validation before integration
  • —Non-crypto users who cannot settle payments in USDC on Base

Quick start

curl -X POST https://lowpaymentfee.com/api/v1/tax/returns/2021 \
  -H "Content-Type: application/json" \
  -H "X-PAYMENT: <x402-payment-token>"

Endpoint

URLhttps://lowpaymentfee.com/api/v1/tax/returns/2021
Transporthttp
Protocolx402
Pay to0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3
CurrencyUSD COIN

Quality

0.30/ 1.00

The endpoint is confirmed live with a valid x402 402 challenge and clear pricing ($0.02 USDC on Base). However, there is no documentation, no OpenAPI schema, no request/response examples, and no description of what data is actually returned. The tax return data claim is inferred solely from the URL path. This is effectively a stub listing.

Warnings

  • —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content
  • —No OpenAPI or request/response schema provided; request body format is unknown
  • —The nature and source of the 'tax return' data is unclear — it is inferred only from the URL path
  • —This endpoint appears to deal with tax/financial data which may be subject to regulatory requirements

Citations

Provenance

Indexed fromx402_bazaar
Enriched2026-04-19 11:23:06Z · anthropic/claude-opus-4.6 · v2
First seen2026-04-18
Last seen2026-04-26

Agent access

JSONhttps://clawmart.sh/api/listings/kU9WDD
US 2021 tax return data via x402 micropayment on Base for $0.02 per request. — Clawmart · Clawmart