x402-gated portfolio transactions endpoint on Base, paid per-request in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to portfolio transaction data (portfolio ID 68) via the x402 payment protocol. It accepts POST requests and charges $0.02 per call in USDC on the Base network. Payment is handled entirely through the x402 challenge-response mechanism — no API keys or accounts are required.
The parent site (lowpaymentfee.com) hosts a broader suite of x402-gated APIs spanning data analytics, AI/ML inference, finance/Web3 data, and utility services, all priced at $0.02 per request. However, the specific endpoint probed here (/api/v1/portfolios/68/transactions) is not listed on the site's public catalog, suggesting it may be a specialized or less-documented resource. No OpenAPI schema, detailed documentation, or example responses were found for this endpoint; the docs, pricing, and README pages all resolve to a wallet-connect prompt with no substantive content.
The endpoint is confirmed live: it returns a well-formed x402 v1 challenge with USDC (contract 0x8335…2913) on Base, a maxAmountRequired of 20000 base units ($0.02), and a 300-second payment timeout. The payTo address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3.
Capabilities
Use cases
- —Retrieving transaction history for a specific portfolio
- —Integrating portfolio data into automated trading or analytics pipelines
- —Agent-driven financial data retrieval without pre-registration
Fit
Best for
- —Agents needing on-demand portfolio transaction data without signup
- —Developers experimenting with x402 payment flows on Base
- —Micropayment-based access to financial data
Not for
- —Users needing detailed API documentation or schema guarantees before integrating
- —High-volume batch retrieval where per-request pricing is cost-prohibitive
- —Non-crypto-native consumers who cannot produce x402 payment headers
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/68/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation, no OpenAPI schema, no example request/response, and the specific endpoint is not even listed on the provider's public catalog. Effectively a stub with confirmed liveness.
Warnings
- —No OpenAPI schema or endpoint documentation available
- —This specific endpoint (/api/v1/portfolios/68/transactions) is not listed on the provider's public API catalog
- —Docs, pricing, and README pages contain no substantive content (only wallet-connect prompts)
- —Response format and accepted request body are unknown
Citations
- —The endpoint returns a valid x402 v1 challenge with USDC on Base, maxAmountRequired 20000 base units ($0.02)https://lowpaymentfee.com/api/v1/portfolios/68/transactions
- —The site advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/68/transactions