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 is priced at $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no upfront commitments. The x402 payment protocol handles authentication and billing inline: callers attach an X-PAYMENT header with a signed USDC payment, and the server fulfills the request.
The specific endpoint probed (/api/v1/transactions/225) is labeled "Premium API Access" and returns a live 402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base. The payment is settled to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The endpoint accepts POST requests and returns application/json.
The broader platform advertises endpoints for metrics, reports, data export, insights, 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 just show "Connect wallet"), so the actual request/response schemas for individual endpoints are unknown. Without detailed docs or OpenAPI specs, callers will need to experiment or contact the provider to understand input parameters and output formats.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time crypto price feeds and gas estimates with per-call USDC payments
- —Running geocoding or data validation utilities on a pay-as-you-go basis
- —Exporting analytics data or generating reports without subscription commitments
Fit
Best for
- —Developers who want zero-signup, pay-per-call API access
- —Agents and bots that can sign x402 USDC payments on Base
- —Projects needing lightweight access to multiple utility endpoints without managing API keys
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or subscription plans
- —Callers who cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/225 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no documentation for request/response schemas, and all doc pages are empty stubs showing only 'Connect wallet'. The specific purpose of /api/v1/transactions/225 ('Premium API Access') is vague and undocumented.
Warnings
- —No OpenAPI or schema documentation available — all doc/pricing/README pages return only 'Connect wallet'
- —The specific endpoint /api/v1/transactions/225 has a generic 'Premium API Access' label with no description of what it actually returns
- —Request body format and response schema are completely unknown
- —The broad catalog of advertised endpoints (AI, finance, utils) cannot be verified for actual functionality
Citations
- —Platform advertises $0.02/request pricing 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 (0.02 USD) on Base with 300-second timeouthttps://lowpaymentfee.com/api/v1/transactions/225
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/transactions/225
- —Platform lists endpoints for analytics, AI/ML, finance/Web3, and infrastructure utilitieshttps://lowpaymentfee.com