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/389` is listed as "Premium API Access" and returns a 402 challenge requiring payment of up to 20,000 base units of USDC (i.e., $0.02) per call. No API keys or rate limits are required; callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform advertises multiple API categories including 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 listed at the same $0.02/request price point.
However, the specific functionality behind `/api/v1/transactions/389` is not documented beyond the label "Premium API Access." The crawled docs, pricing, and README pages all returned only a "Connect wallet" prompt with no additional content. There is no OpenAPI spec, no request/response schema, and no usage examples available from the crawl. The endpoint is confirmed live (402 challenge captured), but what data or service it actually returns upon successful payment is unknown.
Capabilities
Use cases
- —Accessing premium data or transaction information via a single micropayment
- —Integrating pay-per-use API calls into agent workflows without managing API keys
- —Programmatic access to services priced at $0.02 per request on Base/USDC
Fit
Best for
- —Developers wanting zero-signup, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or guaranteed SLAs before purchasing
- —Anyone without a Base-network USDC wallet or x402-compatible client
- —High-volume consumers who need bulk pricing or rate-limit guarantees
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/389 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is confirmed live with a valid 402 challenge, but there is no documentation, no OpenAPI spec, no request/response schema, and no explanation of what 'Premium API Access' actually returns. The docs, pricing, and README pages are all empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —No documentation available — docs, pricing, and README pages all return only 'Connect wallet' with no content.
- —The specific functionality of /api/v1/transactions/389 ('Premium API Access') is completely undocumented.
- —No OpenAPI spec or request/response schema is provided.
- —No example responses are available to verify what data is returned after payment.
- —The platform lists many API categories (AI, finance, analytics, etc.) but none have visible documentation — it is unclear whether these endpoints are fully functional.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/transactions/389
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/389
- —All endpoints priced at $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com