Pay-per-call portfolio holdings API on Base network via x402 protocol, settled in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to portfolio holdings data (portfolio ID 55) via a POST request. It uses the x402 payment protocol, requiring a per-request micropayment of $0.02 in USDC on the Base network. No API keys or rate limits are imposed; access is granted instantly upon payment.
The endpoint is part of a broader platform (lowpaymentfee.com) that offers various pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities—all priced at $0.02 per request. The specific endpoint `/api/v1/portfolios/55/holdings` appears to serve financial portfolio holdings data, though detailed documentation on the request body schema or response format is not available from the crawled material.
Payment is settled on-chain using USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on the Base L2 network. The x402 challenge specifies a maxAmountRequired of 20000 base units, which equals $0.02 (USDC uses 6 decimals). The payment recipient address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a timeout of 300 seconds.
Capabilities
Use cases
- —Retrieving portfolio holdings data for portfolio #55 programmatically
- —Building automated portfolio tracking dashboards
- —Integrating holdings data into trading bots or analytics pipelines
Fit
Best for
- —Agents needing on-demand portfolio holdings without subscription commitments
- —Developers wanting keyless API access with crypto micropayments
- —Applications requiring low-friction financial data access on Base network
Not for
- —Users who need bulk/batch portfolio data at scale (pay-per-call may add up)
- —Those without USDC on Base network for payment
- —Users needing detailed API documentation or guaranteed SLAs
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/55/holdings \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_token>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear, but there is no documentation on request/response schemas, no OpenAPI spec, and the crawled docs pages are empty ('Connect wallet' only). The specific purpose of portfolio 55 holdings is unclear.
Warnings
- —No request body schema or response schema documented
- —Documentation pages return only 'Connect wallet' with no actual content
- —The specific portfolio (ID 55) purpose and data contents are unknown
- —No examples of successful responses available
Citations
- —Endpoint returns 402 with x402 challenge requiring USDC payment on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/55/holdings
- —Platform pricing is $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/55/holdings