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 43) behind an x402 paywall. The endpoint accepts POST requests and returns application/json responses. Payment is settled on the Base network using USDC (USD Coin) at a cost of $0.02 per request (20,000 base units with 6 decimals). No API keys or rate limits are required — callers simply include an X-PAYMENT header with a valid x402 payment proof.
The broader lowpaymentfee.com platform hosts a variety of x402-gated APIs spanning data analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance/crypto data feeds, and utility services, all priced uniformly at $0.02 per call. However, this specific listing covers only the `/api/v1/emails/43/attachments` endpoint. The purpose and content of "email 43" attachments is not documented — the endpoint appears to be a demonstration or specific data resource rather than a general-purpose email API.
The endpoint is live and returns a proper x402 challenge (HTTP 402) with version 1 of the protocol. Payment is made to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 using USDC contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base. The maximum timeout for payment settlement is 300 seconds.
Capabilities
Use cases
- —Retrieving attachments from a specific email resource behind a micropayment wall
- —Demonstrating x402 protocol payment flows for agent-to-API transactions
- —Programmatic access to email attachment data without API key registration
Fit
Best for
- —Developers experimenting with x402 micropayment protocol on Base
- —Agents that need to fetch email attachment data with per-call payment
- —Low-friction API access without signup or API key management
Not for
- —General-purpose email or mailbox access — this is a single fixed email resource
- —High-volume bulk email processing where per-request fees would accumulate
- —Users who need detailed documentation or schema definitions before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/emails/43/attachments \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation on what the email attachments endpoint actually returns, no request/response schema, and no examples. The crawled docs/pricing/API pages are empty beyond a wallet connect prompt. The endpoint path suggests a very specific resource (email 43) rather than a general-purpose API, and its purpose is unclear.
Warnings
- —No documentation available for this specific endpoint — purpose of 'email 43 attachments' is unknown
- —No request body schema or response schema documented
- —Docs, pricing, API, and README pages all render only a 'Connect wallet' prompt with no useful content
- —This appears to be a fixed resource endpoint (email ID 43) rather than a parameterized email API
Citations
- —Endpoint returns HTTP 402 with x402 version 1 challenge requesting USDC on Basehttps://lowpaymentfee.com/api/v1/emails/43/attachments
- —Price is $0.02 per request across all APIs on the platformhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/emails/43/attachments
- —No API keys, no rate limits, instant access advertisedhttps://lowpaymentfee.com