Pay-per-request API collection on Base via x402 — $0.02/call in USDC, no API keys required.
What it does
lowpaymentfee.com hosts a collection of pay-per-request APIs accessible via the x402 payment protocol on the Base network. The endpoint at `/api/v1/collections/39` is labeled "Premium API Access" and accepts POST requests with an x402 payment header. Payment is settled in USDC (contract 0x8335…2913 on Base) at a maximum cost of $0.02 per request (20,000 base units with 6 decimals). No API keys, rate limits, or upfront commitments are required — each call is individually paid.
The broader platform 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 listed endpoints share the same $0.02/request pricing. However, the specific endpoint `/api/v1/collections/39` does not clearly map to any single one of these categories — it may serve as an aggregated collection endpoint or a gateway to the broader API suite.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled material. The x402 challenge confirms the endpoint is live and accepting payment-gated POST requests, but what data or functionality it actually returns is unknown from the available sources.
Capabilities
Use cases
- —Accessing pay-per-request data or AI endpoints without needing API key registration
- —Making USDC micropayments on Base for individual API calls
- —Integrating x402-compatible agents with a low-cost API collection
Fit
Best for
- —Developers or agents wanting zero-signup, pay-as-you-go API access
- —x402-compatible wallets and autonomous agents on Base
- —Low-volume or experimental usage where per-call pricing is preferred over subscriptions
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume production workloads where per-call costs add up quickly
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/collections/39 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge confirms the endpoint is live with clear pricing ($0.02 USDC on Base), but there is zero documentation on request/response schemas, no OpenAPI spec, and all doc pages render only a wallet-connect prompt. The actual functionality behind this specific endpoint is unknown.
Warnings
- —No OpenAPI or schema documentation available — request and response formats are entirely unknown
- —All documentation pages (docs, API, pricing, README) return only a 'Connect wallet' prompt with no content
- —The specific purpose of /api/v1/collections/39 ('Premium API Access') is unclear — it may differ from the individually listed endpoints
- —No examples or error handling documentation found
Citations
- —Endpoint returns 402 with x402 challenge accepting USDC on Base at maxAmountRequired 20000https://lowpaymentfee.com/api/v1/collections/39
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/collections/39
- —API categories include Data & Analytics, AI & ML, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com