Pay-per-call portfolio holdings API on Base, settled in USDC via x402.
What it does
This endpoint at lowpaymentfee.com returns portfolio holdings data for a given portfolio ID (in this case, portfolio 100). It is part of a broader suite of pay-per-request APIs offered by lowpaymentfee.com spanning data analytics, AI/ML inference, finance, crypto, and utility services. All endpoints use the x402 payment protocol, settling in USDC on the Base network.
The specific endpoint `/api/v1/portfolios/100/holdings` accepts POST requests and returns JSON. The x402 challenge advertises a maximum cost of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 per request (USDC uses 6 decimals). The site's landing page confirms a flat $0.02/request pricing model across all endpoints, with no API keys, no rate limits, and no minimum commitments required.
Documentation 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 holdings response contains or what parameters the POST body accepts. The endpoint is live (returns a valid 402 challenge), but without documentation it is difficult to know what data to send or what to expect back.
Capabilities
Use cases
- —Retrieving current holdings for a specific portfolio
- —Building portfolio tracking dashboards that pay per query
- —Agent-driven portfolio analysis without API key management
Fit
Best for
- —Developers wanting keyless, pay-per-call access to portfolio data
- —AI agents that can settle USDC payments on Base automatically
- —Prototyping portfolio tools without subscription commitments
Not for
- —Users needing detailed API documentation or request/response schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/100/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 no OpenAPI schema, no documentation, no request/response examples, and no description of what the holdings data actually contains. Effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, and README pages all show only 'Connect wallet' with no content
- —No OpenAPI or input/output schema provided; request body format and response structure are unknown
- —The endpoint path is hardcoded to portfolio ID 100; it is unclear whether other portfolio IDs are supported or how they are created
- —The broader site lists many endpoint categories (AI, analytics, finance, utilities) all at $0.02, but none have visible documentation
Citations
- —Flat pricing of $0.02 per request across all endpointshttps://lowpaymentfee.com
- —No API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/100/holdings
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/100/holdings