Retrieve portfolio holdings data via x402 micropayment on Base for $0.02 per request.
What it does
This endpoint at lowpaymentfee.com returns holdings data for portfolio ID 51. 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 infrastructure utilities — all priced at $0.02 per request and settled via x402 using USDC on the Base network.
The specific endpoint `/api/v1/portfolios/51/holdings` accepts POST requests and returns JSON. The x402 challenge confirms it is live, requiring a maximum payment of 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this equals $0.02 per call. Payment is made via the x402 "exact" scheme to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3, with a 300-second timeout window.
Documentation is extremely sparse. The landing page lists available endpoints and pricing but provides no request/response schemas, parameter descriptions, or example payloads. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional content. Because of this, the exact request body format and response structure for the holdings endpoint are unknown and must be discovered experimentally.
Capabilities
Use cases
- —Fetching current holdings for a specific portfolio to display in a dashboard
- —Programmatic portfolio monitoring by AI agents that can pay per call
- —Integrating portfolio data into automated trading or rebalancing workflows
Fit
Best for
- —Agents or apps needing on-demand portfolio holdings without API key management
- —Micropayment-native workflows on Base that want sub-dollar per-call pricing
- —Developers prototyping portfolio tools who want instant access with no signup
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-frequency polling use cases where $0.02 per call adds up quickly
- —Anyone needing holdings for arbitrary portfolio IDs (this endpoint is hardcoded to portfolio 51)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/51/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. However, there is no documentation, no request/response schema, no examples, and the docs pages are empty. The purpose of 'portfolio 51 holdings' is opaque — it's unclear whether this returns real financial data or placeholder content.
Warnings
- —No API documentation available — docs, pricing, and README pages all show only 'Connect wallet' with no content
- —Request body schema and response format are completely unknown; no OpenAPI spec or examples provided
- —The endpoint is scoped to a single hardcoded portfolio ID (51) with no explanation of what this portfolio represents
- —The broader platform lists many endpoints but none have documented schemas — treat all with caution
Citations
- —The endpoint returns a 402 challenge requiring 20,000 base units of USDC on Base (=$0.02)https://lowpaymentfee.com/api/v1/portfolios/51/holdings
- —The platform advertises $0.02 per request across all endpoints with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/51/holdings
- —Docs, API, pricing, and README pages render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs