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 56) behind an x402 paywall. The endpoint 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), with no API keys, rate limits, or subscriptions required.
The provider lowpaymentfee.com hosts a broader suite of x402-gated APIs spanning data analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance/crypto data feeds, and infrastructure utilities — all priced at $0.02 per request. However, this specific listing covers only the `/api/v1/emails/56/attachments` endpoint. The endpoint's purpose and response schema are not documented beyond the generic "Premium API Access" label, so the exact structure of the returned attachment data is unknown.
The endpoint is live: it returns a valid x402 version-1 challenge with an "exact" payment scheme. Payment goes to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) on Base. The maximum timeout for payment settlement is 300 seconds.
Capabilities
Use cases
- —Retrieving email attachments programmatically via micropayment
- —Agent-driven workflows that need to fetch specific email attachment data
- —Demonstrating x402 pay-per-call access patterns for email content
Fit
Best for
- —Agents or scripts that need on-demand email attachment retrieval without API keys
- —Developers exploring x402 micropayment-gated APIs
- —Low-volume, pay-as-you-go access to email data
Not for
- —Bulk email processing or high-volume attachment downloads (no documented batch support)
- —Users who need detailed documentation or guaranteed SLAs
- —Accessing arbitrary emails — this endpoint is scoped to email ID 56
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/56/attachments \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no OpenAPI schema, no documentation of request/response formats, and the endpoint's purpose (email 56 attachments) is opaque. The crawled docs/pricing/API pages all returned only 'Connect wallet' with no useful content. Effectively a stub listing.
Warnings
- —No documentation available — docs, pricing, API, and README pages all return only a wallet-connect prompt with no content
- —Response schema and request body format are completely undocumented
- —The endpoint is hardcoded to email ID 56; it is unclear whether this is a demo or a real resource
- —The provider site lists many API categories but none appear to include an emails endpoint, raising questions about this endpoint's purpose
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 in USDC on Basehttps://lowpaymentfee.com/api/v1/emails/56/attachments
- —All APIs on lowpaymentfee.com are priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/emails/56/attachments