x402-gated premium API endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at `/api/v1/cards/82` is part of the lowpaymentfee.com platform, which offers a collection of x402-protocol pay-per-request APIs spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. Each call is gated by an x402 payment challenge settled in USDC on the Base network at $0.02 per request (20,000 base units with 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an X-PAYMENT header with a valid payment proof.
The specific resource `/api/v1/cards/82` is labeled "Premium API Access" but the platform does not provide further documentation about what data or functionality this particular card ID returns. The broader site lists endpoints for metrics, reports, data export, insights, sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point. It is unclear whether `/api/v1/cards/82` maps to one of these capabilities or is a distinct resource.
The endpoint is live and returns a well-formed x402 v1 challenge via POST. Payment is made to `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) on Base. The response MIME type is `application/json`. Documentation pages (docs, pricing, README) all render only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Programmatic access to a pay-per-request JSON API without needing API keys or subscriptions
- —Agent-driven workflows that settle per-call costs in USDC on Base via x402
- —Exploring x402 protocol integration with low-cost endpoints
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —AI agents that need keyless, pay-as-you-go API access
- —Low-volume callers who want no subscription overhead
Not for
- —Users who need detailed documentation or well-defined schemas before integrating
- —High-volume production workloads where per-request crypto settlement adds latency
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/82 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation, no request/response schema, and no description of what '/api/v1/cards/82' actually returns. The docs, pricing, and README pages are all empty beyond a wallet-connect prompt. The listing is effectively a stub.
Warnings
- —The specific functionality of /api/v1/cards/82 is undocumented — 'Premium API Access' is the only label provided.
- —All documentation pages (docs, pricing, README) render only 'Connect wallet' with no usable content.
- —No request body schema or response schema is available; callers cannot know what to send or expect back.
- —The broader platform lists many endpoint categories but it is unclear which, if any, this card ID corresponds to.
Citations
- —The endpoint returns a valid x402 v1 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/cards/82
- —All listed APIs are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/cards/82