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 set of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are pay-per-request at $0.02 each, settled in USDC on the Base network. No API keys, accounts, or rate limits are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/transactions/104` is listed as "Premium API Access" and returns a 402 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 made to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 using the "exact" scheme 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 data generation — all at the same $0.02 price point. However, documentation is extremely sparse: the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled content. The actual behavior and response format of this specific transactions endpoint is unknown.
Capabilities
Use cases
- —Accessing data analytics and reports without creating an account or managing API keys
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) with per-call USDC payments
- —Fetching real-time crypto prices, gas estimates, and exchange rates via micropayments
- —Geocoding, validation, and data conversion utilities paid per request
Fit
Best for
- —Developers who want zero-friction API access without subscriptions or API key management
- —AI agents that can autonomously pay for API calls using x402 on Base
- —Projects needing low-cost, pay-as-you-go access to diverse utility endpoints
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume consumers who would benefit from bulk pricing or rate-limited plans
- —Anyone without a Base-network USDC wallet or x402-compatible client
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/104 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The purpose of this specific '/transactions/104' endpoint is entirely unclear beyond the generic 'Premium API Access' label. Effectively a stub listing.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README pages all show only 'Connect wallet' with no technical content
- —No OpenAPI or schema definition found for any endpoint
- —The specific purpose and expected input/output of /api/v1/transactions/104 is undocumented
- —The platform lists many endpoint categories but none have documented request/response formats
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/104
- —Platform offers endpoints for analytics, AI/ML, finance/Web3, and infrastructure utilitieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /pricing, /api, /README) render only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs