Pay-per-request API collection on Base via x402 — data, AI, finance, and utility endpoints at $0.02/call.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints accessible via the x402 payment protocol on the Base network. The specific endpoint at `/api/v1/collections/9` is labeled "Premium API Access" and accepts POST requests, settling payments in USDC (contract 0x8335…2913 on Base). The maximum amount required per call is 20,000 base units of USDC (6 decimals), which equals $0.02 USD.
The broader platform advertises four categories of APIs: 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 endpoints are listed at $0.02 per request with no API keys, no rate limits, and no minimum commitments required.
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 schema, no request/response examples, and no detailed documentation available from the crawl. The `/api/v1/collections/9` endpoint itself is live and returns a valid x402 402 challenge, but what data it actually returns upon successful payment is unknown from the available material.
Capabilities
Use cases
- —Accessing data analytics and reports on a per-request payment basis without API keys
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) with micropayments
- —Fetching financial data like token prices, exchange rates, and gas estimates
- —Performing utility operations like geocoding, validation, and data conversion
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —Agents or bots that can settle x402 payments in USDC on Base
- —Users who prefer no-signup, wallet-based API authentication
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or subscription plans
- —Developers not set up with USDC on the Base network
Quick start
# The endpoint requires an x402 payment header (USDC on Base, $0.02/call)
curl -X POST https://lowpaymentfee.com/api/v1/collections/9 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI schema, no request/response examples, and all documentation pages render only 'Connect wallet' with no usable content. The actual functionality behind '/api/v1/collections/9' is undocumented.
Warnings
- —No API documentation available — docs, pricing, API, and README pages all show only 'Connect wallet'
- —No OpenAPI or JSON schema describing request parameters or response format
- —The specific functionality of /api/v1/collections/9 ('Premium API Access') is unclear — it may be a bundle or gateway to other endpoints
- —No request/response examples available to verify what data is returned after payment
Citations
- —The endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/collections/9
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages (docs, api, pricing, README) render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs