x402-gated API collection on Base — pay $0.02 per request in USDC, no keys required.
What it does
lowpaymentfee.com hosts a suite of x402-protocol pay-per-call APIs spanning data analytics, AI/ML inference, finance/crypto market data, and general-purpose utilities. Every endpoint costs $0.02 per request, settled in USDC on the Base network. 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.
The specific endpoint `/api/v1/collections/45` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment scheme is "exact" with a 300-second timeout. The endpoint accepts POST requests and returns `application/json`.
Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema, and no usage examples available from the crawled material. It is unclear what data or functionality the `/api/v1/collections/45` endpoint specifically provides beyond the generic "Premium API Access" label. The broader site advertises categories like sentiment analysis, text summarization, embeddings, price feeds, geocoding, and more, but without documentation it is impossible to confirm what each endpoint actually returns.
Capabilities
Use cases
- —Accessing pay-per-call API endpoints without managing API keys or subscriptions
- —Making low-cost programmatic requests settled in USDC on Base
- —Integrating agent-purchasable endpoints into automated workflows
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously
- —Users who prefer crypto-native micropayments over traditional billing
Not for
- —Users who need detailed API documentation or request/response schemas before integrating
- —High-volume consumers who need bulk pricing or SLAs
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/collections/45 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"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 spec, no documentation beyond a wallet-connect prompt, no request/response schema, and no indication of what data '/api/v1/collections/45' actually returns. This is effectively a stub listing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet' with no content.
- —No OpenAPI or schema definition found; request and response formats are unknown.
- —The purpose of /api/v1/collections/45 ('Premium API Access') is completely unspecified — it is unclear what data or service it provides.
- —The broader site lists many endpoints (analytics, AI, finance, utils) but none have documented schemas or examples.
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/collections/45
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The site lists APIs across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /pricing, /api, /README) render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs