Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no commitments required. The x402 protocol handles payment inline: callers attach a payment header to each request and receive the response immediately.
The specific endpoint at `/api/v1/transactions/336` is listed as "Premium API Access" and returns an x402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this equals $0.02 per call, consistent with the site's advertised pricing. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The platform advertises additional endpoints including 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. However, documentation beyond the landing page is essentially empty (all sub-pages just show "Connect wallet"), so the actual behavior, input schemas, and response formats for these endpoints are unknown. The specific purpose of the `/api/v1/transactions/336` endpoint is not documented beyond its generic "Premium API Access" label.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, gas estimates, and exchange rates
- —Running utility operations like geocoding, validation, and data conversion on a per-call basis
- —Integrating pay-per-use APIs into autonomous agent workflows via x402
Fit
Best for
- —Developers wanting zero-setup, pay-as-you-go API access
- —AI agents that can settle payments via x402 on Base
- —Projects needing low-cost micropayment-gated endpoints
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/336 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing. However, documentation is essentially nonexistent — all doc/pricing/API pages render only "Connect wallet" with no content. The specific purpose of /api/v1/transactions/336 is undocumented, there is no input/output schema, and no example responses are available. The listing is effectively a stub.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) are all empty — only showing 'Connect wallet'
- —The specific purpose and expected input/output of /api/v1/transactions/336 ('Premium API Access') is not documented anywhere
- —No OpenAPI spec, no request/response examples, and no detailed endpoint descriptions available
- —The platform advertises many endpoints but none have documented schemas or behavior
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/transactions/336
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com