x402-gated API platform on Base offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-protocol API marketplace that gates access to a variety of endpoints behind per-request micropayments settled in USDC on the Base network. The specific endpoint at `/api/v1/cards/73` is listed as "Premium API Access" and costs up to $0.02 per call (maxAmountRequired of 20,000 base units of USDC, which has 6 decimals = $0.02). Payment is made via the x402 `exact` scheme with no API keys, no rate limits, and no upfront commitments required.
The broader platform advertises four categories of endpoints: 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 listed endpoints share the same $0.02/request pricing. The endpoint is live and returns a proper 402 challenge when called without payment.
Note that the specific functionality behind `/api/v1/cards/73` is not documented beyond the generic "Premium API Access" label. There is no OpenAPI schema, no request/response examples, and the docs, pricing, and API pages all render only a "Connect wallet" prompt with no additional technical detail. Agents should treat this endpoint with caution until more documentation is available.
Capabilities
Use cases
- —Paying per-request for API access without needing API keys or subscriptions
- —Integrating x402-compatible agents with a low-cost endpoint marketplace
- —Accessing data, AI, finance, or utility services via micropayments on Base
Fit
Best for
- —Agents that support x402 payment protocol and want frictionless API access
- —Developers exploring pay-per-use API models without signup
- —Low-volume or sporadic API consumers who want to avoid subscriptions
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or rate-limited plans
- —Anyone unable to settle payments in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/73 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, there is no OpenAPI schema, no request/response examples, no documentation of what /api/v1/cards/73 actually returns, and the docs pages are empty beyond a wallet connect prompt. The listing is effectively a stub with confirmed liveness.
Warnings
- —No documentation available for /api/v1/cards/73 — the specific functionality behind 'Premium API Access' is unknown.
- —Docs, pricing, API, and README pages all render only 'Connect wallet' with no technical content.
- —No OpenAPI spec or request/response schema provided.
- —The endpoint path '/api/v1/cards/73' does not match any of the advertised API categories on the homepage, raising questions about what it actually does.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 in USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base network using the exact scheme.https://lowpaymentfee.com/api/v1/cards/73
- —All listed endpoints are priced at $0.02/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 & Machine Learning, Finance & Web3, and Infrastructure categories.https://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with 6 decimals.https://lowpaymentfee.com/api/v1/cards/73