Pay-per-request email attachment retrieval via x402 on Base (USDC).
What it does
This endpoint at lowpaymentfee.com provides access to email attachments via a POST request to `/api/v1/emails/42/attachments`. It is part of a broader platform offering dozens of pay-per-call API endpoints across data analytics, AI/ML, finance, infrastructure, and more — all settled on-chain using USDC on the Base network through the x402 protocol.
The specific endpoint listed here costs $0.02 per request (20,000 base units of USDC with 6 decimals). Payment is handled inline via the X-PAYMENT header; no API keys, subscriptions, or rate limits are required. The x402 challenge was successfully captured, confirming the endpoint is live and accepting payments to address `0x1A2B...85F3` using USDC (`0x8335...2913`) on Base.
Documentation is extremely sparse. The crawled docs, pricing, and API pages all returned only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema, and no explanation of what the email attachments endpoint actually returns or what input it expects. The endpoint path suggests retrieval of attachments for a specific email (ID 42), but whether this is a demo resource, a parameterized path, or something else is unclear. The platform's landing page confirms uniform $0.02 pricing and lists the endpoint categories but provides no per-endpoint documentation.
Capabilities
Use cases
- —Retrieving email attachments programmatically with per-request crypto payment
- —Agent-driven workflows that need to fetch email data without subscription overhead
- —Integrating on-chain micropayments for document/attachment access
Fit
Best for
- —Developers wanting zero-signup, pay-as-you-go email attachment access
- —AI agents that can settle x402 payments autonomously on Base
- —Prototyping workflows that need instant API access without API key management
Not for
- —Production systems requiring detailed API documentation and SLAs
- —Users who need bulk email processing at high volume with predictable costs
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/42/attachments \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02/request in USDC on Base), but there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page, and no explanation of what this specific endpoint does or accepts. This is effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —All doc/pricing/API pages return only 'Connect wallet' with no technical content
- —The endpoint path '/api/v1/emails/42/attachments' is unexplained — unclear if '42' is a fixed demo ID or a parameterized path
- —No request body schema or response schema provided anywhere
- —Functionality of the email attachments endpoint is entirely unclear
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/emails/42/attachments
- —Uniform pricing of $0.02 per request across all endpoints, no API keys, no rate limitshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/emails/42/attachments