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/5` accepts POST requests and charges $0.02 per call (20,000 base units of USDC on the Base network, where USDC has 6 decimals). Payment is handled inline via the X-PAYMENT header — no API keys, accounts, or rate limits are required.
The provider operates a broader platform offering dozens of pay-per-call endpoints across categories including data & analytics, AI/ML (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints share the same $0.02/request pricing model 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 substantive content. The specific functionality of the `/api/v1/emails/5` endpoint is not documented; the path suggests it may retrieve or process a specific email resource (ID 5), but the exact input/output schema is unknown. The x402 challenge confirms the endpoint is live and accepting payment-gated POST requests.
Capabilities
Use cases
- —Accessing email data or processing via a single paid API call
- —Integrating pay-per-use email functionality into agent workflows
- —Testing x402 payment protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment-gated APIs
- —Agents needing no-signup, no-key API access on Base
- —Low-volume, pay-as-you-go email operations
Not for
- —High-volume email sending or marketing automation (no documented bulk support)
- —Users needing detailed API documentation or guaranteed SLAs
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/5 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no documentation for the /api/v1/emails/5 endpoint — no input schema, no output schema, no examples, and no explanation of what it actually does. The docs/pricing/README pages are all 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.
- —The exact purpose and input/output schema of /api/v1/emails/5 is unknown; the path suggests a specific email resource but this is speculative.
- —No OpenAPI spec or AI plugin manifest found.
- —The endpoint name 'Premium API Access' is generic and does not describe the actual functionality.
Citations
- —The endpoint returns a 402 challenge requesting 20,000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/emails/5
- —All endpoints are priced at $0.02/request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers endpoints across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/emails/5