x402-gated premium API access on Base, pay $0.02 per request in USDC — no API keys required.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" behind an x402 payment wall on the Base network. The provider operates a suite of pay-per-call APIs spanning data & analytics, AI/ML inference, finance & Web3 data, and infrastructure utilities — all priced at $0.02 per request, settled in USDC on Base.
The specific endpoint `/api/v1/charges/317` is listed as "Premium API Access" and accepts POST requests. Payment is handled via the x402 protocol: callers receive a 402 challenge containing the payment parameters (asset, amount, payTo address) and must attach an `X-PAYMENT` header with a valid payment proof. The max amount required is 20,000 base units of USDC (6 decimals), which equals $0.02. No API keys, rate limits, or upfront commitments are advertised.
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no description of what data or functionality this particular charge endpoint returns. The endpoint is confirmed live (402 challenge captured), but the actual payload delivered after payment is unknown from the available material.
Capabilities
Use cases
- —Accessing premium data or services with per-request USDC micropayments on Base
- —Agent-driven API consumption without pre-registration or API key management
- —Programmatic pay-as-you-go access to a generic premium endpoint
Fit
Best for
- —Developers or agents wanting zero-signup, pay-per-call API access
- —x402-compatible clients on the Base network
- —Low-cost micropayment experimentation ($0.02/call)
Not for
- —Users needing detailed documentation or known response schemas before purchasing
- —High-throughput use cases where per-call crypto settlement overhead matters
- —Anyone without a Base-network USDC wallet
Quick start
# 1. Send a POST to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/charges/317
# 2. Parse the 402 JSON for payment params (payTo, asset, maxAmountRequired)
# 3. Construct and sign an x402 payment proof
# 4. Retry with the X-PAYMENT header:
curl -X POST https://lowpaymentfee.com/api/v1/charges/317 \
-H "X-PAYMENT: <signed-payment-proof>"Example
Response
{
"error": "X-PAYMENT header is required",
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3",
"scheme": "exact",
"network": "base",
"mimeType": "application/json",
"resource": "https://lowpaymentfee.com/api/v1/charges/317",
"description": "Premium API Access",
"maxAmountRequired": "20000",
"maxTimeoutSeconds": 300
}
],
"x402Version": 1
}Endpoint
Quality
The endpoint is confirmed live with a valid 402 challenge and clear pricing ($0.02 USDC on Base). However, there is no OpenAPI schema, no documentation of request parameters or response format, and no examples of what the endpoint actually returns after payment. The docs pages are empty stubs. The specific functionality behind 'Premium API Access' at /charges/317 is entirely unknown.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or schema describing request parameters or response format for this endpoint.
- —The actual data or service delivered after successful payment is unknown from available material.
- —The endpoint path '/api/v1/charges/317' does not match any of the advertised API categories on the homepage, making its purpose unclear.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/charges/317
- —All APIs are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The provider offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with 6 decimalshttps://lowpaymentfee.com/api/v1/charges/317