Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint `/api/v1/transfers/138` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) per call. No API keys or rate limits are required; callers simply attach an x402 payment header to each request.
The broader platform advertises multiple API 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 utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request and settle in USDC on Base.
However, the specific functionality behind the `/api/v1/transfers/138` endpoint is not documented beyond the label "Premium API Access." The crawled docs, pricing, and README pages all returned only a "Connect wallet" prompt with no additional technical documentation, schemas, or example payloads. Without further information it is unclear what data or service this particular endpoint returns when a valid payment is provided.
Capabilities
Use cases
- —Accessing premium API services with per-request USDC micropayments on Base
- —Agent-driven workflows that need keyless, on-demand API access
- —Programmatic data retrieval without subscription commitments
Fit
Best for
- —Developers who want pay-as-you-go API access without API keys
- —AI agents that can settle x402 payments autonomously
- —Users already holding USDC on the Base network
Not for
- —Users who need detailed API documentation or guaranteed SLAs before purchasing
- —Anyone without a Base-compatible wallet or USDC balance
- —High-volume consumers who would benefit from bulk pricing or subscriptions
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transfers/138 \
-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 it accepts USDC on Base at $0.02/request. However, there is no documentation of what the endpoint actually returns, no request/response schemas, and the docs/pricing/README pages are all blank beyond a wallet-connect prompt. The specific purpose of '/api/v1/transfers/138' is unknown.
Warnings
- —The exact functionality of /api/v1/transfers/138 ('Premium API Access') is undocumented — it is unclear what data or service is returned upon payment.
- —All documentation pages (docs, pricing, README, api) returned only 'Connect wallet' with no technical content.
- —No OpenAPI spec, request schema, or response schema is available.
- —The broader platform lists many endpoint categories (AI, finance, analytics, etc.) but none are verified beyond the landing page descriptions.
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC ($0.02) on Base network.https://lowpaymentfee.com/api/v1/transfers/138
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base is used for payment.https://lowpaymentfee.com/api/v1/transfers/138
- —Multiple API categories are listed including Data & Analytics, AI & ML, Finance & Web3, and Infrastructure.https://lowpaymentfee.com