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 4) 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 provider lowpaymentfee.com hosts a broad suite of x402-gated APIs spanning data & analytics, AI/ML inference, finance/Web3, and infrastructure utilities — all priced uniformly at $0.02 per request. This specific endpoint sits under an emails resource path, suggesting it retrieves attachment data for a given email. No API keys or rate limits are advertised; access is granted purely through the x402 payment protocol.
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The endpoint is confirmed live (returns a valid 402 challenge), but the actual behavior, required request body fields, and response format are unknown beyond the declared mimeType of application/json.
Capabilities
Use cases
- —Programmatically retrieving email attachments behind a micropayment wall
- —Agent-driven workflows that need to fetch specific email attachment data
- —Pay-per-use access to email content without API key management
Fit
Best for
- —Agents or bots that need on-demand email attachment retrieval
- —Developers experimenting with x402 payment protocol integrations
- —Use cases requiring keyless, pay-per-call API access
Not for
- —Bulk email processing (no documented batch endpoints; $0.02 per request adds up)
- —Users who need detailed API documentation or guaranteed SLAs
- —Accessing arbitrary emails (endpoint is hardcoded to email ID 4)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/4/attachments \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and network. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and the endpoint path is hardcoded to a single email ID. The actual functionality and response format are entirely unknown.
Warnings
- —No API documentation available — docs, pricing, and README pages only show 'Connect wallet'
- —No OpenAPI or JSON schema describing request body or response format
- —Endpoint path is hardcoded to email ID 4; unclear if other email IDs are accessible
- —The purpose and content of the 'email attachments' resource is undocumented and unverifiable
Citations
- —Endpoint returns a valid x402 challenge with maxAmountRequired of 20000 in USDC on Base networkhttps://lowpaymentfee.com/api/v1/emails/4/attachments
- —All APIs on lowpaymentfee.com are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/emails/4/attachments