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 21) behind an x402 paywall. It accepts POST requests and returns JSON. Payment is settled in USDC on the Base network using the x402 "exact" scheme.
The endpoint is part of a broader platform (lowpaymentfee.com) that offers a variety of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $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 this particular endpoint — retrieving attachments for email ID 21 — is narrowly scoped and not well-documented. The x402 challenge confirms it is live and accepting payments of up to 20,000 base units of USDC (6 decimals), which equals $0.02. No OpenAPI schema, request body documentation, or response examples were found in the crawled material. The docs, pricing, and API pages all returned only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Programmatically retrieving email attachments without API key registration
- —Agent-driven workflows that need to fetch specific email attachments on demand
- —Demonstrating x402 micropayment integration for content access
Fit
Best for
- —Developers experimenting with x402 payment protocols
- —AI agents that need to fetch email attachments autonomously
- —Low-friction, keyless API access to email data
Not for
- —Bulk email processing or mailbox management
- —Users who need access to arbitrary email IDs (this endpoint is scoped to email 21)
- —Applications requiring detailed API documentation or SLAs
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/21/attachments \
-H "X-PAYMENT: <x402-payment-proof>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no documentation for request/response schemas, no OpenAPI spec, and the docs pages are empty. The endpoint is narrowly scoped to a single email ID with no explanation of what it returns or what inputs it accepts.
Warnings
- —No API documentation available — docs, pricing, and API pages all return only a 'Connect wallet' prompt with no content.
- —Endpoint is hardcoded to email ID 21; unclear if other email IDs are accessible or what the broader email API looks like.
- —No request body schema or response schema documented anywhere.
- —No OpenAPI or ai-plugin manifest found.
Citations
- —The endpoint returns a 402 challenge with x402Version 1, accepting USDC on Base network with maxAmountRequired of 20000 base units ($0.02).https://lowpaymentfee.com/api/v1/emails/21/attachments
- —The platform advertises $0.02 per request pricing with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base network.https://lowpaymentfee.com/api/v1/emails/21/attachments