Pay-per-call API platform on Base via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. Every endpoint is priced at $0.02 per request, payable in USDC on the Base network. The x402 protocol means there are no API keys, no sign-ups, and no rate limits — callers simply attach a payment header to each request.
The specific endpoint at `/api/v1/transactions/163` is listed as "Premium API Access" and returns `application/json`. The x402 challenge confirms it accepts POST requests with an exact-scheme payment of up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is sent to `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 beyond the landing page is essentially empty (all sub-pages only show "Connect wallet"), so the actual request/response schemas for this and other endpoints are unknown. Without documentation or OpenAPI specs, callers will need to experiment to discover the expected input format and response structure.
Capabilities
Use cases
- —Accessing premium API data without creating accounts or managing API keys
- —Making one-off paid API calls from autonomous agents using x402 on Base
- —Integrating pay-as-you-go API access into Web3 workflows
Fit
Best for
- —Developers wanting zero-signup, pay-per-use API access
- —AI agents that can settle payments via x402 on Base
- —Quick prototyping without API key management overhead
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume use cases where per-request pricing at $0.02 adds up significantly
- —Users without USDC on Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/163 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and confirms pricing and payment details, but there is no OpenAPI spec, no documentation, no request/response schema, and no examples. All doc pages return only 'Connect wallet'. The specific purpose of /api/v1/transactions/163 ('Premium API Access') is vague and undocumented.
Warnings
- —No OpenAPI or schema documentation available — all doc/pricing/README pages are empty stubs showing only 'Connect wallet'.
- —The purpose and expected input/output of /api/v1/transactions/163 is unclear; 'Premium API Access' is a generic label with no further detail.
- —The broader platform lists many endpoints (AI, finance, utils) but none have documented schemas or examples.
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 (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/transactions/163
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /api, /pricing, /README) contain no substantive contenthttps://lowpaymentfee.com/docs