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 provides access to portfolio holdings data via a POST request to `/api/v1/portfolios/42/holdings`. It uses the x402 payment protocol on the Base network, accepting USDC (contract 0x8335…2913) with a maximum cost of $0.02 per request (20,000 base units at 6 decimals). No API keys or rate limits are required — each call is individually settled on-chain.
The provider's landing page advertises a broad suite of APIs spanning data & analytics, AI/ML inference, finance & Web3 market data, and infrastructure utilities, all priced uniformly at $0.02 per request. However, the specific endpoint listed here targets portfolio holdings, which falls under the finance/Web3 category. The x402 challenge was successfully captured (HTTP 402 with valid accepts payload), confirming the endpoint is live.
Documentation beyond the landing page is extremely thin — the /docs, /api, /pricing, and /README pages all returned 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 path includes a hardcoded portfolio ID (42), and it is unclear whether other portfolio IDs are supported or how they are discovered.
Capabilities
Use cases
- —Retrieve holdings data for a specific portfolio on demand
- —Integrate portfolio position data into trading bots or dashboards
- —Agent-driven portfolio analysis without managing API keys
Fit
Best for
- —Developers wanting keyless, pay-per-call access to portfolio data
- —AI agents that can settle x402 payments on Base
- —Quick prototyping without subscription commitments
Not for
- —Users needing detailed API documentation or schema guarantees before integrating
- —High-frequency bulk data retrieval where per-call pricing adds up
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/42/holdings \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no request/response examples, and all documentation pages return only a wallet-connect prompt. The endpoint's actual input parameters and output format are unknown.
Warnings
- —No API documentation available — /docs, /api, /pricing, and /README all return only a 'Connect wallet' prompt
- —No OpenAPI or JSON schema describing request body or response format
- —Endpoint path contains a hardcoded portfolio ID (42); unclear if other IDs are valid
- —The nature and source of the 'holdings' data is unspecified — could be mock/demo data
Citations
- —Endpoint returns HTTP 402 with x402 challenge on Base network using USDChttps://lowpaymentfee.com/api/v1/portfolios/42/holdings
- —Max amount required is 20000 base units of USDC (6 decimals = $0.02)https://lowpaymentfee.com/api/v1/portfolios/42/holdings
- —All APIs priced at $0.02/request with no API keys, no rate limitshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/42/holdings