Pay-per-call premium API on Base via x402 — $0.02/request in USDC, no API keys required.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints accessible via the x402 payment protocol on the Base network. This specific endpoint (`/api/endpoint-55`) is listed as "Premium API Access" and accepts USDC payments on Base. The x402 challenge confirms the endpoint is live and requires a maximum of 20,000 base units of USDC (i.e., $0.02) per request. No API keys, rate limits, or upfront commitments are needed — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader lowpaymentfee.com platform advertises 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 listed endpoints share the same $0.02/request pricing. However, `/api/endpoint-55` does not correspond to any of the named endpoints on the site's landing page, so its exact functionality is unclear.
The endpoint accepts POST requests and returns `application/json`. Payment settles to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) on Base. The x402 challenge specifies a 300-second payment timeout. Documentation pages beyond the landing page are effectively empty (showing only a "Connect wallet" prompt), so request/response schemas are unknown.
Capabilities
Use cases
- —Accessing a premium API endpoint without needing to register or obtain API keys
- —Making one-off paid API calls settled in USDC on Base
- —Integrating pay-per-request services into agent workflows via x402
Fit
Best for
- —Developers who want instant API access without signup or subscriptions
- —AI agents that can settle x402 payments autonomously on Base
- —Users comfortable paying per-request in USDC
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —Anyone looking for free or trial-tier API access
- —Developers who need non-crypto payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/endpoint-55 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge with clear pricing ($0.02 USDC on Base). However, the specific functionality of /api/endpoint-55 is unknown — it doesn't match any named endpoint on the site. Documentation pages are empty, no OpenAPI schema exists, and no request/response examples are available. This is effectively a stub listing.
Warnings
- —The endpoint path /api/endpoint-55 does not match any of the named endpoints listed on the provider's landing page; its actual functionality is unknown.
- —All documentation pages (/docs, /api, /pricing, /README) returned only a 'Connect wallet' prompt with no usable content.
- —No OpenAPI schema, request format, or response format is documented anywhere.
- —The exact purpose and data returned by this endpoint cannot be determined from available materials.
Citations
- —The x402 challenge confirms the endpoint is live, accepts POST, and requires max 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/endpoint-55
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with 6 decimals, making 20000 base units equal to $0.02https://lowpaymentfee.com/api/endpoint-55
- —The site advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The site lists endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages show only a Connect wallet prompt with no substantive contenthttps://lowpaymentfee.com/docs