x402basequality 0.35

Pay-per-call API platform on Base with USDC payments via x402 — $0.02/request, no API keys needed.

Price
0.02 USDC / call
Protocol
x402
Verified
no
Endpoint
https://lowpaymentfee.com/api/v1/invoices/18

What it does

lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across data analytics, AI/ML inference, finance/Web3, and utility services. All endpoints are priced at $0.02 per request, settled in USDC on the Base network. The x402 protocol means no API keys, no accounts, and no rate limits — callers simply attach a payment header to each request.

The specific endpoint at `/api/v1/invoices/18` is listed as "Premium API Access" and returns an x402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment scheme is "exact" with a 300-second timeout. The endpoint accepts POST requests and returns application/json.

The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation — all at the same $0.02 price point. However, documentation beyond the landing page is extremely sparse (docs, pricing, and API pages all render only a "Connect wallet" prompt), so the actual functionality, request/response schemas, and data sources behind each endpoint are unverified.

Capabilities

x402-paymentusdc-basepay-per-requestdata-analyticsai-inferencesentiment-analysistext-summarizationclassificationembeddingsfinance-datacrypto-quotesgeocodingutility-services

Use cases

  • —Agents needing on-demand API access without managing API keys or subscriptions
  • —Programmatic access to AI inference (sentiment, summarization, classification, embeddings) at micro-payment scale
  • —Fetching real-time crypto quotes, gas estimates, or exchange rates with per-call billing
  • —Geocoding or data validation as a lightweight utility service

Fit

Best for

  • —AI agents and bots that can settle x402 payments autonomously
  • —Developers wanting zero-signup, pay-as-you-go API access on Base
  • —Low-volume or sporadic API consumers who don't want monthly commitments

Not for

  • —High-volume production workloads where per-call overhead matters (no bulk pricing documented)
  • —Users who need detailed API documentation, SLAs, or guaranteed uptime
  • —Consumers without a Base-compatible USDC wallet

Quick start

curl -X POST https://lowpaymentfee.com/api/v1/invoices/18 \
  -H "Content-Type: application/json" \
  -H "X-PAYMENT: <x402-payment-header>"

Endpoint

URLhttps://lowpaymentfee.com/api/v1/invoices/18
Transporthttp
Protocolx402
Pay to0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3
CurrencyUSD COIN

Quality

0.35/ 1.00

The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no request/response examples, and all documentation pages beyond the landing page are empty stubs. The specific purpose of /api/v1/invoices/18 ('Premium API Access') is vague and undocumented. This is effectively a stub listing.

Warnings

  • —Documentation pages (/docs, /pricing, /api, /README) all return only a 'Connect wallet' prompt with no actual content.
  • —No OpenAPI or schema available — request and response formats for this endpoint are unknown.
  • —The endpoint path '/api/v1/invoices/18' with description 'Premium API Access' is ambiguous; its actual functionality is unclear.
  • —The broader platform claims many endpoint categories (AI, finance, geo, etc.) but none are individually verified beyond the landing page listing.

Citations

Provenance

Indexed fromx402_bazaar
Enriched2026-04-18 21:52:07Z · anthropic/claude-opus-4.6 · v2
First seen2026-04-18
Last seen2026-04-23

Agent access

JSONhttps://clawmart.sh/api/listings/PPPD5B
Pay-per-call API platform on Base with USDC payments via x402 — $0.02/request, no API keys needed. — Clawmart · Clawmart