x402-gated premium API access on Base, pay $0.02 per request in USDC — no API keys required.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to gate access to a variety of endpoints spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. Each call costs $0.02 in USDC on the Base network, with no API keys, rate limits, or upfront commitments required. Payment is handled inline via the X-PAYMENT header.
The specific endpoint `/api/v1/cards/72` is listed as "Premium API Access" and returns an x402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02. The endpoint accepts POST requests and returns application/json. The broader platform also offers endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, conversion, and data export — all at the same $0.02 per-call price point.
Documentation is extremely sparse: the /docs, /pricing, /api, 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 `/api/v1/cards/72` is unclear — the name "Premium API Access" and the path segment "cards/72" do not reveal what data or service is returned.
Capabilities
Use cases
- —Accessing premium API data 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 various utility and data endpoints
Fit
Best for
- —Developers wanting zero-signup, pay-per-use API access
- —AI agents that can settle x402 payments autonomously
- —Users comfortable with USDC on Base for micropayments
Not for
- —Users who need detailed API documentation or schemas before integrating
- —Anyone requiring free or subscription-based access without crypto payments
- —Production workloads that need SLA guarantees or support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/72 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, confirming it accepts USDC payments on Base at $0.02 per call. However, there is no documentation, no OpenAPI spec, no request/response schema, and no explanation of what /api/v1/cards/72 actually returns. The docs pages are all blank wallet-connect prompts. The listing is essentially a stub.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all show only 'Connect wallet' with no content.
- —The purpose of /api/v1/cards/72 ('Premium API Access') is completely undocumented; it is unclear what data or service this endpoint provides.
- —No OpenAPI spec or request/response schema is available.
- —No examples of successful responses exist in the crawl material.
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC on Base (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913), equaling $0.02.https://lowpaymentfee.com/api/v1/cards/72
- —The platform advertises $0.02 per request with no API keys, no rate limits, and instant access on the Base network.https://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories.https://lowpaymentfee.com
- —The /docs, /pricing, /api, and /README pages render only a 'Connect wallet' prompt with no documentation content.https://lowpaymentfee.com/docs