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. Every endpoint costs $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no subscriptions required. The specific endpoint at `/api/v1/transactions/211` is listed as "Premium API Access" and returns an x402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base.
The platform advertises categories including 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 (geocoding, validation, conversion, generation). All endpoints use the same $0.02 pricing model. Payment is settled on-chain via the x402 protocol using the USDC contract at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base.
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 crawl. The endpoint is confirmed live (returns a valid 402 challenge), but the actual functionality behind the "Premium API Access" label at `/api/v1/transactions/211` is unclear from available materials.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time finance and crypto market data on a per-request basis
- —Running utility operations like geocoding, validation, and data conversion with micropayments
- —Programmatic agents purchasing API calls autonomously via x402 on Base
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that need autonomous endpoint purchasing via x402
- —Projects needing low-cost per-request pricing without subscriptions
Not for
- —High-volume production workloads needing SLAs or guaranteed uptime
- —Users who need detailed API documentation or OpenAPI specs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/211 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. 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/211 ('Premium API Access') is unclear. Score reflects a live but poorly documented stub.
Warnings
- —No API documentation available — /docs, /api, /pricing, and /README all render only 'Connect wallet'
- —No OpenAPI or schema definition found for any endpoint
- —The specific functionality of /api/v1/transactions/211 ('Premium API Access') is not described anywhere
- —No request or response examples available; input/output formats are unknown
- —The broad catalog of endpoints (AI, finance, analytics, utils) is advertised but none have documented schemas
Citations
- —Endpoint returns x402 challenge with maxAmountRequired of 20000 base units USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/211
- —All endpoints priced at $0.02 per request with no API keys, no rate limitshttps://lowpaymentfee.com
- —Platform offers Data & Analytics, AI & ML, Finance & Web3, and Infrastructure endpoint categorieshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/transactions/211