x402basequality 0.35

Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.

Price
0.02 USDC / call
Protocol
x402
Verified
no
Endpoint
https://lowpaymentfee.com/api/v1/inbox/22

What it does

lowpaymentfee.com is an x402-enabled API platform that provides a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/inbox/22` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). Payment is handled via the x402 protocol — no API keys, accounts, or subscriptions are required; callers simply attach an X-PAYMENT header with a valid payment proof.

The wider platform advertises four endpoint categories: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at the same $0.02/request price point.

However, the specific functionality of the `/api/v1/inbox/22` endpoint is unclear. The path pattern ("inbox/22") does not match any of the documented API categories, and the description is simply "Premium API Access" with no further detail. There is no OpenAPI spec, no request/response schema documentation, and the crawled docs pages (pricing, README, API) all returned only a "Connect wallet" prompt with no additional content. Prospective callers should be aware that the actual behavior of this particular endpoint is undocumented.

Capabilities

x402-paymentusdc-settlementbase-networkpay-per-requestno-api-keypost-endpoint

Use cases

  • —Programmatic access to pay-per-call API services without account registration
  • —Agent-driven API consumption where payment is settled on-chain per request
  • —Testing x402 protocol integrations with a low-cost endpoint

Fit

Best for

  • —Developers or agents wanting zero-signup, pay-as-you-go API access
  • —x402 protocol experimentation on Base with USDC
  • —Low-cost per-request API consumption without rate limits

Not for

  • —Users who need detailed API documentation or guaranteed SLAs before calling
  • —High-volume batch workloads where per-request pricing may add up
  • —Anyone who needs to understand the exact response schema before paying

Quick start

# The endpoint requires an x402 X-PAYMENT header with a valid USDC payment proof on Base.
# Without payment, it returns a 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/inbox/22
# Response: 402 with x402 challenge JSON describing payment requirements.
# After constructing a valid payment, attach it:
curl -X POST https://lowpaymentfee.com/api/v1/inbox/22 \
  -H "X-PAYMENT: <base64-encoded-payment-proof>"

Example

Response

{
  "error": "X-PAYMENT header is required",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3",
      "scheme": "exact",
      "network": "base",
      "mimeType": "application/json",
      "resource": "https://lowpaymentfee.com/api/v1/inbox/22",
      "description": "Premium API Access",
      "maxAmountRequired": "20000",
      "maxTimeoutSeconds": 300
    }
  ],
  "x402Version": 1
}

Endpoint

URLhttps://lowpaymentfee.com/api/v1/inbox/22
Transporthttp
Protocolx402
Pay to0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3
CurrencyUSD COIN

Quality

0.35/ 1.00

The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC on Base at $0.02/request. However, there is no OpenAPI spec, no request/response schema, no documentation of what this specific endpoint actually does, and the path 'inbox/22' doesn't match any documented category. The listing is essentially a stub with confirmed liveness but unknown functionality.

Warnings

  • —The specific functionality of /api/v1/inbox/22 is completely undocumented — the path does not match any of the advertised API categories
  • —No OpenAPI spec or request/response schema is available for any endpoint on this platform
  • —Documentation pages (/pricing, /README, /api) returned only 'Connect wallet' with no useful content
  • —The purpose of 'inbox/22' is unclear — it may be a generic or placeholder endpoint

Citations

Provenance

Indexed fromx402_bazaar
Enriched2026-04-21 21:37:38Z · anthropic/claude-opus-4.6 · v2
First seen2026-04-21
Last seen2026-04-22

Agent access

JSONhttps://clawmart.sh/api/listings/YAAWQy
Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request. — Clawmart · Clawmart