Retrieve portfolio holdings via x402 micropayment on Base for $0.02 per request.
What it does
This endpoint at lowpaymentfee.com returns holdings data for portfolio ID 9. It is part of a broader platform (lowpaymentfee.com) that offers dozens of pay-per-call API endpoints spanning data analytics, AI/ML inference, finance/Web3 market data, and utility services — all priced at $0.02 per request and settled via x402 using USDC on the Base network.
The specific endpoint `/api/v1/portfolios/9/holdings` accepts POST requests and is gated by an x402 payment challenge. The challenge specifies a maximum amount of 20,000 base units of USDC (asset contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base, 6 decimals), which equals $0.02 USD per call. Payment is made via the `exact` scheme to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. No API keys or rate limits are advertised; access is instant upon payment.
Documentation is extremely sparse — the docs, pricing, and API pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI schema, no request/response examples, and no description of what fields the holdings response contains or what parameters the POST body accepts. The endpoint appears live (402 challenge confirmed), but the lack of documentation makes it difficult to use without experimentation.
Capabilities
Use cases
- —Retrieving current holdings for a specific portfolio
- —Integrating portfolio data into automated trading or reporting workflows
- —Agent-driven portfolio monitoring with per-call micropayments
Fit
Best for
- —Developers needing on-demand portfolio holdings without subscription commitments
- —AI agents that can settle x402 USDC payments on Base
- —Applications requiring low-cost, keyless API access to financial data
Not for
- —Users who need detailed API documentation or request/response schemas before integrating
- —Bulk data retrieval where per-request pricing would be cost-prohibitive
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/9/holdings \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is zero documentation on request parameters, response schema, or what 'portfolio 9 holdings' actually contains. No OpenAPI spec, no examples, and all doc pages are empty wallet-connect stubs.
Warnings
- —No API documentation available — docs, pricing, and API pages all show only 'Connect wallet' with no content
- —No request body schema or response schema documented; callers must guess at the POST body format
- —The endpoint is hardcoded to portfolio ID 9 — unclear if other portfolio IDs are available or what this portfolio represents
- —No OpenAPI or machine-readable spec provided
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/9/holdings
- —All endpoints on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/9/holdings