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/wire/21` is listed as "Premium API Access" and charges up to 20,000 base units of USDC (i.e., $0.02 per call, since USDC uses 6 decimals). No API keys, rate limits, or upfront commitments are required — each request is paid for individually via an X-PAYMENT header.
The broader platform advertises multiple API categories: 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 listed at the same $0.02/request price point. However, the specific functionality behind `/api/v1/wire/21` is not documented beyond the label "Premium API Access," and no request/response schemas are provided for any endpoint.
The docs, pricing, API, and README pages all render only a "Connect wallet" prompt with no further documentation. Without OpenAPI specs, example payloads, or detailed endpoint descriptions, it is difficult to determine what data or service this particular endpoint returns. The platform is live (returns a valid 402 challenge), but documentation is essentially absent.
Capabilities
Use cases
- —Programmatic access to a pay-per-call API without needing API keys or subscriptions
- —Agent-driven workflows that pay per request using USDC on Base
- —Testing x402 protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that need keyless, on-demand API access settled in USDC
- —Low-volume or sporadic API consumers who prefer pay-per-use
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/wire/21 \
-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, there is no OpenAPI schema, no request/response examples, and all documentation pages render only a wallet-connect prompt. The actual functionality behind '/api/v1/wire/21' is unknown beyond its label.
Warnings
- —No documentation available — docs, pricing, API, and README pages all show only 'Connect wallet'
- —No OpenAPI or request/response schema provided for any endpoint
- —The specific functionality of /api/v1/wire/21 ('Premium API Access') is undocumented and unclear
- —Cannot verify what data or service is actually returned upon successful payment
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/wire/21
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/wire/21