x402-gated email endpoint on Base, pay $0.02 per request in USDC — no API keys required.
What it does
This endpoint at `/api/v1/emails/4` is part of the lowpaymentfee.com platform, a collection of x402-protocol pay-per-request APIs settled in USDC on the Base network. The specific purpose of the `/emails/4` route is not documented beyond the generic label "Premium API Access," so its exact functionality is unclear. It likely provides some form of email-related data or service, but no schema, example payloads, or detailed documentation are available.
The endpoint is live and returns a valid x402 challenge (HTTP 402) requesting payment of up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 per request given USDC's 6 decimals. Payment is made via the x402 `exact` scheme with a 300-second timeout. No API keys, rate limits, or subscriptions are required — callers simply attach an `X-PAYMENT` header with a valid payment proof.
The broader lowpaymentfee.com platform advertises endpoints across data/analytics, AI/ML (sentiment, summarization, classification, embeddings), finance/Web3 (price feeds, exchange rates, gas estimates), and infrastructure utilities (geocoding, validation, conversion). All are priced at $0.02 per call. However, documentation pages (`/docs`, `/pricing`, `/README`) returned only a "Connect wallet" prompt with no substantive content, so the actual capabilities and response formats of these endpoints remain unverified.
Capabilities
Use cases
- —Fetching email-related data or performing email operations on a per-request payment basis
- —Agent-driven workflows that need email functionality without managing API keys or subscriptions
- —Programmatic access to email services settled in USDC on Base L2
Fit
Best for
- —Developers or agents wanting zero-signup, pay-per-use email API access
- —x402-compatible agents that can settle USDC payments on Base
- —Low-volume or sporadic email data needs where $0.02/request is cost-effective
Not for
- —High-volume email sending or marketing automation (no bulk pricing or documented throughput)
- —Users who need detailed API documentation, schemas, or guaranteed SLAs before integrating
- —Non-crypto users who cannot settle payments in USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/4 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation, no request/response schema, and no explanation of what the /emails/4 endpoint actually does. The docs, pricing, and README pages are all empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —The exact functionality of /api/v1/emails/4 is undocumented — 'Premium API Access' is a generic label applied to all endpoints on this platform.
- —All documentation pages (/docs, /pricing, /README) returned no substantive content, only a 'Connect wallet' prompt.
- —No request body schema or response schema is available; callers must guess at the expected input format.
- —The broader platform lists many endpoint categories (AI, finance, infrastructure) but none appear to have public documentation verifying their functionality.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/emails/4
- —All APIs on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/emails/4
- —Documentation pages (/docs, /pricing, /README) returned only 'Connect wallet' with no substantive contenthttps://lowpaymentfee.com/docs