x402 pay-per-call API suite on Base — data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is a collection of x402-protocol APIs that accept per-request micropayments in USDC on the Base network. The site advertises endpoints across four 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 priced at $0.02 per request with no API keys, no rate limits, and no minimum commitments.
The specific endpoint `/api/v1/nfts/88` is listed as "Premium API Access" and returns a live x402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals = $0.02) via the "exact" payment scheme. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The endpoint accepts HTTP POST and returns application/json.
Note: The `/api/v1/nfts/88` path suggests NFT-related data, but no further documentation describes the request body schema or response format. The site's docs, pricing, and README pages all resolve to a wallet-connect stub with no additional content. Without an OpenAPI spec, example payloads, or detailed documentation, the exact functionality of this endpoint remains unclear.
Capabilities
Use cases
- —Programmatic agents paying per-call for NFT or premium data without managing API keys
- —Integrating low-cost micropayment-gated endpoints into autonomous workflows
- —Accessing on-demand data feeds settled instantly in USDC on Base
Fit
Best for
- —Developers or agents wanting key-free, pay-as-you-go API access
- —x402-compatible wallets and agent frameworks on Base
- —Low-volume or bursty workloads where per-request pricing is economical
Not for
- —High-volume consumers needing bulk/subscription pricing
- —Users who need detailed API documentation or guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/nfts/88 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, confirming pricing and payment details. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page listing, and the NFT-specific endpoint purpose is unexplained. Effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —The /api/v1/nfts/88 path purpose is undocumented — 'Premium API Access' is the only description
- —Docs, pricing, and README pages all resolve to a wallet-connect stub with no content
- —Request body format and response structure are unknown
Citations
- —All endpoints priced at $0.02/request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (6 decimals = $0.02) on Basehttps://lowpaymentfee.com/api/v1/nfts/88
- —Site lists four API categories: Data & Analytics, AI & ML, Finance & Web3, Infrastructurehttps://lowpaymentfee.com