Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that provides a collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and general utility services. All endpoints are paid per-request using USDC on the Base network via the x402 protocol — no API keys, no rate limits, and no subscriptions required.
The specific endpoint at `/api/v1/payments/399` is listed as "Premium API Access" and accepts POST requests. The x402 challenge indicates a maximum cost of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 per call (USDC uses 6 decimals). The broader platform advertises a uniform $0.02/request price across all its endpoints, covering categories like sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, and more.
Documentation beyond the landing page is sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawl. The endpoint is live (returns a valid 402 challenge), but without documentation it is unclear what request body this particular endpoint expects or what response payload it returns.
Capabilities
Use cases
- —Agents needing on-demand AI inference (sentiment, summarization, classification) without API key management
- —Fetching real-time crypto token quotes or gas estimates with per-call payment
- —Running geocoding or data validation as a utility service from an autonomous workflow
- —Exporting analytics data or generating insights on a pay-as-you-go basis
Fit
Best for
- —AI agents that need keyless, pay-per-call access to diverse API endpoints
- —Developers prototyping with low-commitment, no-subscription API access
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume production workloads where per-call pricing at $0.02 adds up quickly
- —Users who need detailed API documentation, SDKs, or guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/399 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, there is no OpenAPI spec, no request/response schema, and all documentation pages render only a wallet-connect prompt. The purpose of this specific '/payments/399' endpoint is unclear beyond the generic 'Premium API Access' label. Effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available — request/response formats are unknown
- —All doc pages (/docs, /pricing, /api, /README) return only a 'Connect wallet' prompt with no content
- —The specific purpose of /api/v1/payments/399 ('Premium API Access') is not explained anywhere; it may be a generic or placeholder endpoint
- —No examples, error codes, or rate limit information documented
Citations
- —Uniform pricing of $0.02 per request across all endpoints, no API keys, no rate limitshttps://lowpaymentfee.com
- —Endpoint returns x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/payments/399
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/payments/399
- —Platform offers endpoints in categories: Data & Analytics, AI & Machine Learning, Finance & Web3, Infrastructurehttps://lowpaymentfee.com