Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The site hosts a broad catalog of pay-per-request APIs spanning data & analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, payable in USDC on the Base network with no API keys, no rate limits, and no commitments required.
The specific endpoint `/api/v1/payments/239` is listed as "Premium API Access" and returns a valid x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 exact scheme, settling to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The endpoint accepts HTTP POST 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 documentation, and no examples of what this particular endpoint actually returns. The site's landing page confirms the pricing model and lists the available API categories, but the specific functionality behind `/api/v1/payments/239` is unclear. It may be a generic payments endpoint or a gateway to the broader API catalog.
Capabilities
Use cases
- —Programmatic pay-per-call API access without API key management
- —Agent-driven API consumption with automatic USDC micropayments on Base
- —Accessing data, AI, finance, or utility endpoints with no subscription commitment
Fit
Best for
- —Developers or agents wanting frictionless pay-per-use API access
- —Use cases requiring no rate limits and instant access
- —Crypto-native workflows settling payments on Base L2
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume use cases where per-request pricing at $0.02 may be costly compared to subscription plans
- —Users without access to USDC on Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/239 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no documentation, no OpenAPI spec, no request/response schema, and no examples. The specific purpose of /api/v1/payments/239 is unclear beyond the generic label "Premium API Access."
Warnings
- —No documentation available — /docs, /pricing, /api, and /README pages all show only 'Connect wallet' with no content
- —No OpenAPI or schema definition for request or response payloads
- —The specific functionality of /api/v1/payments/239 is undocumented and unclear
- —No examples of expected input or output are provided anywhere in the crawled material
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 (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/payments/239
- —Site offers APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com