Pay-per-call premium API endpoint on Base via x402, settled in USDC at $0.02/request.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints accessible via the x402 payment protocol on the Base network. This specific endpoint (`/api/endpoint-18`) is labeled "Premium API Access" and accepts POST requests. Payment is settled in USDC (contract 0x8335…2913 on Base) with a maximum amount of 20,000 base units, which equals $0.02 per request (USDC uses 6 decimals). No API keys or rate limits are advertised; access is granted instantly upon valid x402 payment.
The broader lowpaymentfee.com platform advertises endpoints spanning 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 priced at $0.02 per request. However, this particular endpoint (`/api/endpoint-18`) does not correspond to any of the named endpoints listed on the site, so its exact functionality is unclear. The x402 challenge confirms the endpoint is live and accepting payment negotiations, but no OpenAPI schema, request/response examples, or detailed documentation were found.
Because the docs, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content, the actual behavior behind this endpoint remains undocumented. Agents should treat this as a generic premium endpoint whose concrete capabilities are unverified.
Capabilities
Use cases
- —Programmatic access to a premium API endpoint with per-call USDC micropayments
- —Agent-driven workflows that need keyless, instant API access on Base
- —Testing x402 payment protocol integrations against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment flows
- —Agents that can settle USDC payments on Base L2
- —Low-cost per-request API consumption without subscriptions
Not for
- —Users who need documented request/response schemas before integrating
- —High-throughput use cases where per-call payment overhead is impractical
- —Anyone requiring fiat-only payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/endpoint-18 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The x402 challenge confirms the endpoint is live and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no documentation, no request/response examples, and the endpoint path does not match any named service on the site. Functionality is entirely unknown.
Warnings
- —Endpoint /api/endpoint-18 does not match any of the named endpoints listed on the provider's homepage — its actual functionality is undocumented.
- —All documentation pages (docs, pricing, README, api) returned only 'Connect wallet' with no substantive content.
- —No OpenAPI spec, request schema, or response schema available — agents cannot predict what this endpoint returns.
- —The provider site lists many endpoints but none at this specific path; this may be a test or placeholder endpoint.
Citations
- —The x402 challenge returns maxAmountRequired of 20000 in USDC (6 decimals) on Base, equaling $0.02 per request.https://lowpaymentfee.com/api/endpoint-18
- —The site advertises $0.02/request pricing with no API keys, no rate limits, and instant access on the Base network.https://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.https://lowpaymentfee.com/api/endpoint-18
- —Documentation, pricing, README, and API pages all returned only 'Connect wallet' with no further content.https://lowpaymentfee.com/docs