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 & machine learning, 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 payment protocol allows agents and clients to pay per call by attaching a payment header to each HTTP request.
The specific endpoint at `/api/v1/charges/235` 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 translates to $0.02 per request, consistent with the site's advertised pricing. 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. However, documentation pages (docs, pricing, README) all returned only a "Connect wallet" prompt with no substantive content, so the actual behavior and schemas of these endpoints remain undocumented. Without request/response schemas or examples, it is unclear what inputs each endpoint expects or what outputs it returns.
Capabilities
Use cases
- —Agents needing on-demand API access without API key registration
- —Pay-per-call AI inference (sentiment, summarization, classification, embeddings)
- —Fetching real-time crypto quotes and gas estimates with micropayments
- —Geocoding and data conversion utilities paid in USDC
Fit
Best for
- —AI agents that can settle x402 payments on Base
- —Developers wanting zero-commitment, pay-as-you-go API access
- —Use cases requiring low-cost ($0.02) per-request pricing without rate limits
Not for
- —Users who need detailed API documentation and request/response schemas before integrating
- —High-volume workloads where subscription pricing would be more cost-effective
- —Users without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/235 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI schema, no request/response examples, and all documentation pages return only a wallet-connect prompt. The actual functionality behind 'Premium API Access' at /charges/235 is entirely opaque.
Warnings
- —No API documentation available — docs, pricing, and README pages all return only 'Connect wallet' with no content.
- —No request or response schema provided for any endpoint, including this one.
- —The specific purpose of /api/v1/charges/235 ('Premium API Access') is unclear — it does not map to any of the named endpoints listed on the homepage.
- —Cannot verify what data or service is actually delivered after payment.
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge for /api/v1/charges/235 requests maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/charges/235
- —Platform offers endpoints across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com