Pay-per-call email API on Base via x402 — $0.02/request in USDC, no API keys required.
What it does
This endpoint at lowpaymentfee.com provides a premium email-related API accessible via the x402 payment protocol. The specific resource `/api/v1/emails/10` accepts POST requests and charges $0.02 per call (20,000 base units of USDC on the Base network, where USDC uses 6 decimals). Payment is made inline via the X-PAYMENT header — no API keys, accounts, or rate limits are required.
The provider hosts a broader suite of pay-per-call APIs spanning 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 $0.02 per request and settle on the Base network using USDC.
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 schema, no request/response examples, and no description of what the `/api/v1/emails/10` endpoint actually does or what parameters it expects. The endpoint is live (returns a valid 402 challenge), but the lack of documentation makes it difficult to use without experimentation.
Capabilities
Use cases
- —Sending or retrieving email data via a single paid API call
- —Integrating email functionality into an agent workflow without managing API keys
- —Testing x402 payment protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment-gated APIs
- —Agent-based workflows needing keyless, pay-per-call email access
- —Low-volume, on-demand email operations without subscription commitments
Not for
- —High-volume email sending requiring bulk pricing or SLAs
- —Users who need detailed API documentation before integration
- —Production systems requiring guaranteed uptime and support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/10 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is zero documentation on what the email endpoint does, what request body it expects, or what it returns. No OpenAPI schema, no examples, and all doc pages are empty. This is effectively a stub listing.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or request/response schema provided for the /api/v1/emails/10 endpoint.
- —The purpose of the endpoint (send email? retrieve email? validate email?) is completely unclear from available materials.
- —The '/10' path segment is unexplained — it may be an ID, a batch size, or something else entirely.
Citations
- —The endpoint returns a 402 challenge requesting 20,000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/emails/10
- —All APIs are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The provider offers APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/emails/10