x402-gated email endpoint on Base, pay $0.02 per request in USDC with no API keys.
What it does
This endpoint at lowpaymentfee.com provides premium API access via the x402 payment protocol. The specific resource `/api/v1/emails/16` appears to be part of a broader platform offering dozens of pay-per-call endpoints spanning data analytics, AI/ML inference, finance, crypto, and utility services — all gated behind x402 micropayments on the Base network.
Payment is settled in USDC (contract 0x8335…2913 on Base) using the "exact" scheme. The x402 challenge advertises a maxAmountRequired of 20,000 base units, which at 6 decimals for USDC equals $0.02 per request. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The specific functionality of the `/api/v1/emails/16` resource is not documented in the crawled material. The landing page lists categories like Data & Analytics, AI & ML, Finance & Web3, and Infrastructure utilities, but does not enumerate an "emails" category. The endpoint accepts POST requests and returns application/json. Without further documentation or example responses, the exact data returned by this email-related endpoint remains unclear.
Capabilities
Use cases
- —Retrieving email-related data or records via a single paid API call
- —Integrating low-cost email data lookups into agent workflows
- —Programmatic access to email resources without managing API keys or subscriptions
Fit
Best for
- —Agents needing on-demand email data with no subscription overhead
- —Developers who want to pay per call in USDC on Base
- —Low-volume or sporadic usage patterns where flat-rate plans are wasteful
Not for
- —High-volume email sending or transactional email delivery
- —Users who need detailed documentation or SLA guarantees before integrating
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/16 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base). However, the specific /emails/16 resource is not documented anywhere in the crawl material, there is no OpenAPI schema, no example request/response, and the docs/pricing/README pages all returned only a 'Connect wallet' stub. The actual functionality is unknown.
Warnings
- —The /api/v1/emails/16 endpoint is not listed on the provider's landing page among its advertised APIs — its purpose is unclear.
- —Documentation pages (/docs, /pricing, /README) returned no useful content, only a 'Connect wallet' prompt.
- —No OpenAPI spec, no request/response examples, and no description of what the emails endpoint returns.
- —The endpoint path includes a numeric ID (16), suggesting it may reference a specific record rather than a general-purpose API.
Citations
- —The platform advertises $0.02 per request with no API keys, no rate limits, and instant access on the Base network.https://lowpaymentfee.com
- —The x402 challenge specifies maxAmountRequired of 20000 base units in USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base.https://lowpaymentfee.com/api/v1/emails/16
- —The landing page lists Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories but does not list an emails category.https://lowpaymentfee.com