Retrieve email attachments via x402 micropayment on Base for $0.02 per request.
What it does
This endpoint at lowpaymentfee.com provides access to email attachments (specifically email ID 95) behind an x402 paywall. Payment is settled in USDC on the Base network at $0.02 per request (maxAmountRequired of 20,000 base units with 6 decimals). The endpoint accepts POST requests and returns application/json responses. No API keys or rate limits are required — callers simply include an X-PAYMENT header with a valid x402 payment proof.
lowpaymentfee.com is a broader platform offering a variety of pay-per-call APIs across categories including data analytics, AI/ML inference, finance/Web3, and infrastructure utilities, all priced at $0.02 per request. However, this specific endpoint (/api/v1/emails/95/attachments) is not listed on the site's main catalog, and its purpose — retrieving attachments for a specific email — is not documented beyond the generic "Premium API Access" label. There is no OpenAPI schema, no request/response examples, and the docs, pricing, and API pages all render only a "Connect wallet" prompt with no additional content.
Because the endpoint is live (returning a well-formed 402 challenge) but lacks any documentation about what request body to send or what the response payload looks like, agents will need to experiment or have prior knowledge of the API contract to use it effectively.
Capabilities
Use cases
- —Retrieving email attachments programmatically via micropayment
- —Agent-driven email data extraction behind a paywall
- —Accessing stored email content without API key management
Fit
Best for
- —Agents that need on-demand email attachment retrieval with crypto micropayments
- —Developers experimenting with x402 payment protocol on Base
- —Workflows requiring keyless, pay-per-use API access
Not for
- —Bulk email processing (no documented batch support, $0.02 per request adds up)
- —Users who need detailed API documentation or guaranteed SLAs
- —Non-crypto users who cannot settle payments in USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/95/attachments \
-H "X-PAYMENT: <x402_payment_proof>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing, but there is zero documentation on request format, response schema, or what the endpoint actually returns. The email-specific path (/emails/95/attachments) is not listed in the site's public catalog, and all doc pages render only 'Connect wallet' with no content. Effectively a stub.
Warnings
- —No OpenAPI schema or request/response documentation available
- —This specific endpoint (/api/v1/emails/95/attachments) is not listed on the provider's public API catalog
- —All documentation pages (docs, pricing, API, README) render only 'Connect wallet' with no useful content
- —Purpose and data returned by this endpoint are unclear beyond the generic 'Premium API Access' label
- —The hardcoded email ID (95) suggests this may be a demo or test endpoint rather than a general-purpose API
Citations
- —Endpoint returns HTTP 402 with x402 challenge, maxAmountRequired 20000 in USDC on Basehttps://lowpaymentfee.com/api/v1/emails/95/attachments
- —USDC asset contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/emails/95/attachments
- —Site advertises $0.02 per request, no API keys, no rate limits, Base networkhttps://lowpaymentfee.com
- —Docs, pricing, API, and README pages all show only 'Connect wallet'https://lowpaymentfee.com/docs