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 for email ID 40) behind an x402 paywall. It accepts POST requests and returns JSON. Payment is settled in USDC on the Base network at $0.02 per call (maxAmountRequired of 20,000 base units with 6 decimals = $0.02).
The endpoint is part of a broader platform (lowpaymentfee.com) that offers a variety of x402-gated APIs spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities — all priced at $0.02 per request. The platform advertises no API keys, no rate limits, and instant access. However, the specific endpoint being listed here — `/api/v1/emails/40/attachments` — is not documented on the site's landing page among the advertised APIs, so its exact functionality and response schema are unclear.
The x402 challenge was successfully captured (HTTP 402 with a valid accepts block), confirming the endpoint is live. The payment is routed to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) on Base. No OpenAPI spec, detailed documentation, or example responses were found in the crawl.
Capabilities
Use cases
- —Retrieving attachments from a specific email record via programmatic API call
- —Agent-driven workflows that need to fetch email attachment data with per-call micropayments
- —Integrating email attachment retrieval into automated pipelines without API key management
Fit
Best for
- —Agents needing on-demand email attachment access with no subscription
- —Developers experimenting with x402 micropayment-gated APIs
- —Low-volume, pay-per-use email data retrieval
Not for
- —Bulk email processing or high-volume attachment downloads (no documented batch support)
- —Users who need detailed documentation or guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/40/attachments \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_token>"Endpoint
Quality
The endpoint is live (valid 402 challenge captured) and pricing is clear ($0.02 USDC on Base). However, this specific email attachments endpoint is not listed among the site's advertised APIs, there is no OpenAPI spec, no documentation, no example request/response schemas, and the crawled docs/pricing/README pages returned only 'Connect wallet' with no useful content. The purpose and data returned are largely unknown.
Warnings
- —This specific endpoint (/api/v1/emails/40/attachments) is not listed among the provider's advertised APIs on the landing page — its purpose and output are unclear.
- —No OpenAPI spec, request schema, or response schema available.
- —Documentation pages (/docs, /pricing, /README) returned no useful content beyond 'Connect wallet'.
- —The endpoint appears to reference a hardcoded email ID (40); generalizability to other email IDs is unknown.
Citations
- —The x402 challenge returns maxAmountRequired of 20000 in USDC on Base networkhttps://lowpaymentfee.com/api/v1/emails/40/attachments
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/emails/40/attachments
- —Platform advertises $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The landing page lists APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories but does not include an emails endpointhttps://lowpaymentfee.com