x402-gated portfolio transactions endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com provides access to portfolio transaction data via a POST request to `/api/v1/portfolios/35/transactions`. It is part of a broader platform (lowpaymentfee.com) that offers dozens of pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3 data, and utility services — all gated behind the x402 payment protocol on the Base network.
The specific endpoint probed here charges up to $0.02 per request (maxAmountRequired of 20,000 base units of USDC, which has 6 decimals = $0.02). Payment is settled in USDC on Base to the specified payTo address. The x402 challenge confirms the endpoint is live and accepts POST requests with an `X-PAYMENT` header. No API keys or rate limits are advertised; access is granted purely through per-call micropayments.
Documentation on the site is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what fields the transactions endpoint accepts or returns. The endpoint's purpose (portfolio transactions for portfolio ID 35) can only be inferred from the URL path. Without documentation, callers must experiment or rely on the generic x402 outputSchema (which only confirms HTTP POST is the method).
Capabilities
Use cases
- —Fetching transaction history for a specific portfolio via micropayment
- —Integrating pay-per-call financial data into agent workflows
- —Accessing portfolio data without API key registration
Fit
Best for
- —Agents that can settle x402 USDC payments on Base
- —Developers wanting keyless, pay-per-use portfolio data access
- —Micropayment-based API consumption without subscriptions
Not for
- —Users needing detailed API documentation or schemas before integrating
- —High-volume batch queries where per-call pricing is inefficient
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/35/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no request/response documentation, no examples, and the docs pages are empty. The purpose of this specific endpoint (portfolio 35 transactions) is unclear beyond what the URL implies. This is effectively a stub listing.
Warnings
- —No API documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content
- —No OpenAPI or request/response schema provided; request body format is unknown
- —The endpoint targets a hardcoded portfolio ID (35); unclear if this is a demo or production resource
- —No information on what 'transactions' data is returned or what POST body fields are accepted
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/35/transactions
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/35/transactions
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com