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 and the server fulfills the request upon verification.
The specific endpoint at `/api/v1/transactions/338` is listed as "Premium API Access" and accepts POST requests. Its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The broader platform advertises endpoints for 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 is extremely sparse: the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no actual technical documentation, schemas, or example payloads. Without documentation it is unclear what request bodies these endpoints expect or what response formats they return.
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 payment basis
- —Building agent workflows that pay per request using x402 on Base
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle payments via x402/USDC on Base
- —Projects needing quick access to multiple utility endpoints without signup
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/338 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, there is no documentation, no OpenAPI schema, no request/response examples, and the docs/pricing/README pages are all blank beyond a wallet connect prompt. The purpose of this specific '/transactions/338' endpoint is unclear beyond the generic 'Premium API Access' label.
Warnings
- —No API documentation available — docs, pricing, and README pages all show only 'Connect wallet'
- —No request or response schema provided for this endpoint or any other endpoint on the platform
- —The specific purpose of /api/v1/transactions/338 ('Premium API Access') is not explained anywhere
- —Cannot verify what data or functionality any of the advertised endpoints actually return
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 with 300s timeouthttps://lowpaymentfee.com/api/v1/transactions/338
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Docs, API, pricing, and README pages render only 'Connect wallet' with no technical contenthttps://lowpaymentfee.com/docs