Pay-per-call API platform on Base network via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad set of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are pay-per-request using USDC on the Base network, settled via the x402 protocol. The platform advertises $0.02 per request across all endpoints, with no API keys, no rate limits, and no minimum commitments.
The specific probed endpoint (`/api/v1/transactions/69`) is labeled "Premium API Access" and returns a valid x402 challenge requesting up to 20,000 base units of USDC (0.02 USDC, i.e., $0.02) on Base. The payment is made to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using the USDC contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`. The endpoint accepts POST requests and returns `application/json`.
The broader platform lists endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation — all at the same $0.02 price point. However, 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 spec, no request/response schema documentation, and no usage examples available from the crawl. The actual functionality behind these endpoints is unverified beyond the x402 challenge.
Capabilities
Use cases
- —Accessing premium API data without managing API keys or subscriptions
- —Making one-off paid API calls from autonomous agents using USDC on Base
- —Integrating pay-per-use analytics, AI inference, or financial data into workflows
Fit
Best for
- —Developers wanting zero-friction API access with crypto micropayments
- —AI agents that can settle x402 payments autonomously on Base
- —Projects needing simple pay-as-you-go API access without signup
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —Applications requiring high-throughput bulk access with negotiated pricing
- —Teams that cannot transact in USDC on the Base network
Quick start
# The endpoint requires an x402 payment header with USDC on Base.
# Using curl with a hypothetical x402 client:
curl -X POST https://lowpaymentfee.com/api/v1/transactions/69 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and well-formed, confirming the endpoint exists and accepts payment at $0.02 USDC on Base. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The actual functionality behind 'Premium API Access' and the many listed endpoints is entirely unverified.
Warnings
- —Documentation pages (docs, API, pricing, README) all return only a 'Connect wallet' prompt with no usable content.
- —No OpenAPI or schema documentation is available — request and response formats are unknown.
- —The specific functionality of /api/v1/transactions/69 ('Premium API Access') is unclear; the name is generic.
- —The breadth of advertised endpoints (AI, finance, analytics, utils) is unverified; actual capabilities may differ from listings.
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0.02 USDC) on Basehttps://lowpaymentfee.com/api/v1/transactions/69
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/69
- —Platform lists endpoints for analytics, AI/ML, finance/Web3, and infrastructure utilitieshttps://lowpaymentfee.com