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 platform that offers a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are pay-per-request at $0.02 each, settled in USDC on the Base network. No API keys, accounts, or rate limits are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/policies/56` is listed as "Premium API Access" and returns `application/json` via POST. Its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913, which has 6 decimals), equating to $0.02 per call. The payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The platform's landing page advertises additional endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point. However, documentation pages (/docs, /pricing, /api, /README) all returned only a "Connect wallet" prompt with no substantive content, so the actual behavior, input schemas, and response formats of these endpoints are undocumented in the crawled material. The exact functionality behind the `/api/v1/policies/56` path is unclear — the name "Premium API Access" is generic and no input/output schema details are provided beyond the x402 challenge metadata.
Capabilities
Use cases
- —Accessing premium API data without creating an account or managing API keys
- —Making one-off paid API calls from autonomous agents using x402 protocol
- —Paying for API access in USDC on Base L2 with no subscription commitment
Fit
Best for
- —Agents or developers who want frictionless pay-per-call API access
- —x402-compatible clients that can attach payment headers automatically
- —Users who prefer crypto micropayments over traditional API billing
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume consumers who want bulk pricing or subscription discounts
- —Developers who cannot transact in USDC on Base network
Quick start
# The endpoint requires an x402 payment header with USDC on Base.
# First, probe for the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/policies/56
# Then attach a valid X-PAYMENT header per x402 spec:
curl -X POST https://lowpaymentfee.com/api/v1/policies/56 \
-H "X-PAYMENT: <signed-x402-payment-payload>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI schema, no input/output examples, and the purpose of '/api/v1/policies/56' is entirely opaque. All doc pages returned only 'Connect wallet' with no content.
Warnings
- —The exact functionality of /api/v1/policies/56 is unknown — 'Premium API Access' is a generic label with no further description.
- —No documentation is available: /docs, /pricing, /api, and /README all returned only a 'Connect wallet' prompt.
- —No input schema or response schema is documented; callers cannot know what to send or expect back.
- —The platform lists many endpoints on its landing page but none have documented behavior or examples.
Citations
- —All endpoints priced at $0.02 per 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 (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equating to $0.02https://lowpaymentfee.com/api/v1/policies/56
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com