Pay-per-call API platform on Base (USDC) via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint `/api/v1/payments/149` is listed as "Premium API Access" and charges up to 20,000 base units of USDC (i.e., $0.02 per call, since USDC uses 6 decimals). No API keys, rate limits, or upfront commitments are required — each request is individually settled on-chain.
The broader platform advertises several categories of endpoints including 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 endpoints are uniformly priced at $0.02 per request.
However, the specific functionality behind this particular endpoint (`/api/v1/payments/149`) is not documented beyond the label "Premium API Access." There is no OpenAPI schema, no request/response examples, and the docs, pricing, and API pages all resolve to a minimal "Connect wallet" prompt with no further detail. The endpoint is confirmed live (returns a valid 402 x402 challenge), but what data or service it actually returns upon successful payment is unknown.
Capabilities
Use cases
- —Agents that need to call paid APIs without pre-registering for API keys
- —Programmatic access to a pay-per-use endpoint settled in USDC on Base
- —Testing x402 protocol integrations with a low-cost live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —AI agents with USDC wallets on Base that need on-demand API access
- —Low-volume, no-commitment API consumption without signup
Not for
- —Users who need detailed documentation or guaranteed SLAs before paying
- —High-volume use cases where $0.02/request adds up without bulk discounts
- —Anyone who needs to know exactly what the endpoint returns before paying
Quick start
# The endpoint requires an x402 payment header with USDC on Base.
# 1. Send a POST to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/payments/149
# 2. Parse the 402 JSON, construct an X-PAYMENT header
# with a signed USDC transfer of 0.02 USDC to
# 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3
# 3. Resend the POST with the X-PAYMENT header attached.Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, but there is zero documentation on what the endpoint actually returns. No OpenAPI schema, no request/response examples, and the docs pages are empty stubs. The label 'Premium API Access' is generic and uninformative.
Warnings
- —No documentation exists for this specific endpoint — the actual service/data returned is unknown
- —All doc, pricing, API, and README pages resolve to a minimal 'Connect wallet' stub with no content
- —No OpenAPI or schema describing request parameters or response format
- —The endpoint path '/api/v1/payments/149' does not match any of the advertised API categories on the homepage, so its purpose is unclear
Citations
- —The endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/payments/149
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/payments/149