Pay-per-call portfolio holdings API on Base via x402, settled in USDC at $0.02/request.
What it does
This endpoint at lowpaymentfee.com returns portfolio holdings data for a specific portfolio (ID 15) via a POST request. It uses the x402 payment protocol on the Base network, accepting USDC (contract 0x8335…2913) with a maximum charge of $0.02 per request (20,000 base units at 6 decimals). No API keys or rate limits are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The endpoint is part of a broader platform (lowpaymentfee.com) that offers dozens of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and utility services, all priced at $0.02 per request. The specific endpoint listed here falls under the finance/Web3 category and serves portfolio holdings information.
Documentation is extremely sparse. The crawled docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no further 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 confirmed live (returns a proper 402 x402 challenge), but without documentation it is difficult to know exactly what data is returned or what input is expected.
Capabilities
Use cases
- —Retrieving current holdings for a specific investment portfolio
- —Integrating portfolio data into dashboards or trading bots
- —Automated portfolio monitoring by AI agents paying per request
Fit
Best for
- —Agents needing on-demand portfolio holdings without subscription commitments
- —Developers who want keyless, pay-per-call access to financial data
- —x402-compatible clients on the Base network
Not for
- —Users who need detailed API documentation or schema before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone needing holdings for arbitrary portfolio IDs (this endpoint is fixed to portfolio 15)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/15/holdings \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, but there is no OpenAPI schema, no request/response examples, and all documentation pages returned only a wallet-connect prompt. The purpose (portfolio holdings) is only inferable from the URL path; actual input parameters and response shape are unknown.
Warnings
- —No API documentation available — all doc pages return only 'Connect wallet' with no content
- —No OpenAPI or JSON schema describing request parameters or response format
- —Endpoint is hardcoded to portfolio ID 15; unclear if other portfolio IDs are available
- —No example request or response bodies could be sourced
Citations
- —Endpoint returns 402 with x402 challenge accepting USDC on Base network, maxAmountRequired 20000 base unitshttps://lowpaymentfee.com/api/v1/portfolios/15/holdings
- —Platform advertises $0.02 per request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/15/holdings