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 broad catalog of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are paid per-request using USDC on the Base network, with no API keys, no rate limits, and no commitments required. The specific endpoint at `/api/v1/transactions/374` 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 per call (USDC uses 6 decimals).
The platform advertises four categories of APIs: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All are priced uniformly at $0.02 per request. Payment is handled via the x402 protocol's exact scheme, settling on the Base L2 network.
Documentation is extremely sparse — the /docs, /api, /pricing, 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 usage examples available from the crawled material. The endpoint is confirmed live (402 challenge captured), but the lack of documentation makes it difficult to know what request body to send or what response to expect for this particular transaction endpoint.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key signup
- —Fetching real-time financial data like token quotes, gas estimates, and exchange rates on a per-call basis
- —Running data analytics queries and exporting data with per-request USDC micropayments
- —Using utility services like geocoding and validation without rate limits or subscriptions
Fit
Best for
- —Agents and developers who want instant API access without registration or API keys
- —Crypto-native workflows that can pay per-call in USDC on Base
- —Low-volume or bursty usage patterns where subscription pricing is wasteful
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk/subscription pricing
- —Developers without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/374 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live with a valid 402 challenge and clear pricing ($0.02 USDC on Base). However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schema, and no examples. The specific purpose of '/api/v1/transactions/374' is unclear beyond the generic 'Premium API Access' label.
Warnings
- —No API documentation available — /docs, /api, /pricing, and /README pages all render only 'Connect wallet'
- —No OpenAPI or schema definition found for any endpoint
- —The specific purpose and expected request/response format of /api/v1/transactions/374 is undocumented
- —The broad catalog of advertised endpoints (AI, finance, data, utils) cannot be verified for actual functionality
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —402 challenge requests maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/374
- —Platform offers Data & Analytics, AI & ML, Finance & Web3, and Infrastructure API categorieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /api, /pricing, /README) show only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs