Pay-per-call premium API access on Base via x402 — $0.02 per request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. The specific endpoint at `/api/v1/charges/45` is listed as "Premium API Access" and accepts payment via the x402 protocol on the Base network using USDC (contract 0x8335…2913). Each call costs $0.02 (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The provider's landing page advertises four endpoint 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 (geocoding, validation, conversion, generation). All endpoints are uniformly priced at $0.02 per request. The probe confirmed the endpoint is live, returning a well-formed 402 challenge with x402 version 1, an "exact" payment scheme, and a 300-second timeout.
Documentation beyond the landing page is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no additional technical detail. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The exact functionality behind the `/api/v1/charges/45` path is unclear; it may be a generic charge endpoint or a specific resource. Callers should expect JSON responses (mimeType: application/json) via POST.
Capabilities
Use cases
- —Agents needing on-demand API access without pre-registration or API keys
- —Programmatic pay-per-call access to analytics, AI, finance, or utility endpoints
- —Crypto-native applications that settle API costs in USDC on Base
Fit
Best for
- —AI agents or bots that need keyless, instant API access via x402
- —Developers who prefer per-request crypto micropayments over subscriptions
- —Low-volume or sporadic API consumers who want zero commitment
Not for
- —High-volume consumers who need bulk pricing or rate guarantees
- —Users who require detailed API documentation or OpenAPI specs before integrating
- —Teams that cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/45 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live with a valid 402 challenge and clear pricing ($0.02 USDC on Base). However, documentation is essentially nonexistent — no OpenAPI spec, no request/response schemas, no examples, and the specific purpose of /api/v1/charges/45 is undocumented. This is effectively a stub listing.
Warnings
- —No OpenAPI spec or request/response schema available
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content
- —The exact functionality of /api/v1/charges/45 ('Premium API Access') is not documented — unclear what it returns
- —No example requests or responses are available anywhere in the crawled material
Citations
- —Endpoint returns a valid x402 402 challenge with x402Version 1, exact scheme, on Base network using USDChttps://lowpaymentfee.com/api/v1/charges/45
- —maxAmountRequired is 20000 base units of USDC (6 decimals) = $0.02 per requesthttps://lowpaymentfee.com/api/v1/charges/45
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/charges/45
- —Landing page lists uniform $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Provider offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com