Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint `/api/v1/transactions/16` is listed as "Premium API Access" and returns a 402 challenge requiring payment of up to 20,000 base units of USDC (i.e., $0.02) per call. No API keys or rate limits are required; callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform advertises multiple API categories including 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.
However, the specific functionality behind `/api/v1/transactions/16` is not documented beyond the label "Premium API Access." The crawled docs, pricing, and README pages all returned only a "Connect wallet" prompt with no additional content. There is no OpenAPI schema, no request/response examples, and no detailed documentation available for this or any other endpoint on the platform. The endpoint is live and responds with a valid x402 challenge, but what data or service it actually returns upon successful payment is unknown.
Capabilities
Use cases
- —Accessing premium API data with per-request USDC micropayments on Base
- —Integrating pay-as-you-go API calls into agent workflows without API key management
- —Testing x402 protocol payment flows against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents needing keyless, pay-per-call API access on Base
- —Low-volume consumers who prefer no subscription commitments
Not for
- —Users who need detailed API documentation before purchasing
- —High-volume consumers who need bulk pricing or rate guarantees
- —Anyone without a Base-network USDC wallet
Quick start
# The endpoint requires an x402 X-PAYMENT header with a valid payment proof.
# First, fetch the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/transactions/16
# Then construct and attach the X-PAYMENT header per x402 spec
# paying up to $0.02 USDC on Base to 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation, no OpenAPI schema, no request/response examples, and the actual functionality behind 'Premium API Access' is completely undocumented. The docs, pricing, and README pages are all empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —The actual data or service returned by /api/v1/transactions/16 upon successful payment is completely undocumented.
- —All documentation pages (docs, pricing, README, api) returned only 'Connect wallet' with no useful content.
- —No OpenAPI schema or request/response examples are available for any endpoint on the platform.
- —The platform lists many API categories (AI, analytics, finance, etc.) but provides no evidence these endpoints return real data.
Citations
- —Endpoint returns 402 with x402 challenge requiring up to 20,000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/16
- —USDC asset contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/transactions/16
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Multiple API categories listed: Data & Analytics, AI & ML, Finance & Web3, Infrastructurehttps://lowpaymentfee.com