Pay-per-call API suite on Base via x402 — data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com offers a collection of pay-per-request API endpoints settled via the x402 protocol on the Base network using USDC. The specific endpoint at `/api/v1/payments/2` is labeled "Premium API Access" and charges up to 20,000 base units of USDC (i.e., $0.02 per call, since USDC uses 6 decimals). No API keys or accounts are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform advertises four categories of endpoints: 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 with no rate limits or minimum commitments.
Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawl. The endpoint is confirmed live (returns a proper 402 x402 challenge), but without documentation it is unclear what request body this particular endpoint expects or what response payload it returns.
Capabilities
Use cases
- —Agents that need on-demand AI inference (sentiment, summarization, classification, embeddings) without managing API keys
- —Fetching real-time financial data like token quotes, gas estimates, or exchange rates with per-call payment
- —Running geocoding or data validation tasks with no subscription commitment
- —Programmatic data export and analytics queries paid per request via crypto
Fit
Best for
- —AI agents and bots that can settle payments via x402 on Base
- —Developers wanting zero-signup, pay-as-you-go API access
- —Low-volume or bursty workloads where per-call pricing is more economical than subscriptions
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume production workloads where $0.02/request adds up significantly
- —Teams that cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/2 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live with a valid 402 x402 challenge, and the landing page provides a high-level catalog with pricing. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The purpose of this specific '/api/v1/payments/2' endpoint is unclear beyond its label. This is effectively a stub listing.
Warnings
- —No OpenAPI spec or machine-readable schema available
- —All documentation pages (/docs, /pricing, /api, /README) render only 'Connect wallet' with no technical content
- —The specific purpose and expected request/response format of /api/v1/payments/2 ('Premium API Access') is undocumented
- —Cannot verify what data or functionality any of the advertised endpoints actually return
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/payments/2
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/payments/2
- —Platform advertises $0.02/request pricing across all endpoints with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Four endpoint categories: Data & Analytics, AI & Machine Learning, Finance & Web3, Infrastructurehttps://lowpaymentfee.com