Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API marketplace that offers a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no commitments required. The x402 protocol handles payment inline: callers attach a payment header to each HTTP request and receive the response immediately upon settlement.
The specific endpoint at `/api/v1/charges/68` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this equals $0.02 per call. The challenge specifies the `exact` payment scheme 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 essentially empty (docs, pricing, and README pages only show a "Connect wallet" prompt), so the actual behavior and response schemas of individual endpoints are undocumented.
Capabilities
Use cases
- —Agents that need on-demand API access without pre-registration or API keys
- —Programmatic access to utility endpoints (geocoding, validation, conversion) with per-call billing
- —Testing x402 payment protocol integrations against a live endpoint
Fit
Best for
- —Developers exploring x402 pay-per-call patterns on Base
- —AI agents needing keyless, instant API access
- —Low-volume or sporadic API consumers who want no subscriptions
Not for
- —High-volume production workloads where $0.02/request adds up quickly
- —Users who need detailed API documentation and response schemas before integrating
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/68 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, there is no OpenAPI schema, no documentation of request/response formats, and no examples. The docs, pricing, and README pages are all blank beyond a wallet-connect prompt. The specific purpose of '/api/v1/charges/68' labeled 'Premium API Access' is unclear — it doesn't map to any of the named endpoints on the landing page. This is effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, and README pages are empty
- —The endpoint path '/api/v1/charges/68' does not correspond to any of the named endpoints listed on the landing page; its actual functionality is unknown
- —No request or response schema is documented anywhere
- —No examples of successful responses are available
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/charges/68
- —Platform offers endpoints across data analytics, AI/ML, finance/Web3, and infrastructure categorieshttps://lowpaymentfee.com