Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
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/transactions/155` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) per call. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform offers endpoints across four categories: 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 priced at $0.02 per request.
This particular endpoint (`/api/v1/transactions/155`) is labeled "Premium API Access" but no further documentation describes what data or functionality it returns. The docs, pricing, API, and README pages all render only a "Connect wallet" prompt with no additional content. Without schema details or response examples, the actual behavior of this endpoint remains unclear.
Capabilities
Use cases
- —Accessing premium API data without subscription or API key management
- —Making one-off paid API calls settled in USDC on Base
- —Agent-driven programmatic access to paid endpoints via x402 protocol
Fit
Best for
- —Developers wanting zero-signup, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously
- —Users who prefer crypto micropayments over traditional billing
Not for
- —Users needing detailed API documentation or response schemas before purchasing
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Users without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/155 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC on Base at $0.02/request. However, there is no documentation, no OpenAPI schema, no response examples, and no description of what this specific endpoint actually returns. The docs/pricing/README pages are all empty beyond a wallet-connect prompt. The listing is effectively a stub.
Warnings
- —No documentation available — docs, pricing, API, and README pages all show only 'Connect wallet' with no content.
- —The specific functionality of /api/v1/transactions/155 ('Premium API Access') is completely undocumented.
- —No response schema or example responses are available for any endpoint.
- —No OpenAPI specification found.
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC ($0.02) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/155
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories, all at $0.02/requesthttps://lowpaymentfee.com
- —Platform advertises no API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/transactions/155