Pay-per-call API platform on Base via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. Every endpoint is priced at $0.02 per request, paid in USDC on the Base network via the x402 payment protocol. There are no API keys, no rate limits, and no subscription commitments — callers simply attach an X-PAYMENT header with a valid x402 payment proof to each request.
The specific endpoint at `/api/v1/payments/147` is listed as "Premium API Access" and accepts POST requests. The x402 challenge advertises a maxAmountRequired of 20000 base units of USDC (contract 0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The platform also hosts endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point.
Documentation is extremely sparse: the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled material. The endpoint is confirmed live (returns 402 with a valid x402 challenge), but without documentation it is unclear what inputs this specific endpoint expects or what it returns.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) without managing API keys or subscriptions
- —Fetching real-time crypto token quotes and gas estimates via micropayment
- —Running geocoding or data validation calls on a per-request payment basis
- —Exporting analytics data or generating reports with no upfront commitment
- —Integrating pay-per-use endpoints into autonomous AI agent workflows
Fit
Best for
- —AI agents needing keyless, on-demand API access paid in crypto
- —Developers who want to avoid subscription lock-in for low-volume API usage
- —Web3-native applications that can settle payments in USDC on Base
Not for
- —High-volume production workloads where subscription pricing would be cheaper
- —Users without a Base-compatible wallet or USDC holdings
- —Anyone needing detailed API documentation or SLAs before integration
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/147 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, and the landing page describes the platform's catalog and pricing. However, documentation pages are empty (just 'Connect wallet'), there is no OpenAPI spec, no request/response schemas, and no examples. The specific purpose of /api/v1/payments/147 beyond 'Premium API Access' is unknown. This is effectively a stub listing.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) return no useful content — only a 'Connect wallet' prompt.
- —No OpenAPI or schema documentation is available for any endpoint.
- —The specific functionality of /api/v1/payments/147 ('Premium API Access') is undocumented — it is unclear what inputs it expects or what it returns.
- —The broad catalog of endpoints (AI, finance, analytics, utils) is listed on the homepage but none have documented request/response schemas.
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/payments/147
- —Platform offers endpoints for analytics, AI/ML, finance/Web3, and infrastructure utilitieshttps://lowpaymentfee.com
- —Documentation pages render only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs