Portfolio holdings data via x402 micropayment on Base network for $0.02/request
What it does
This endpoint at lowpaymentfee.com provides access to portfolio holdings data (portfolio ID 4) through the x402 payment protocol. It accepts POST requests and returns JSON. Payment is settled on the Base network using USDC (contract 0x8335…2913) at a cost of $0.02 per request (20,000 base units with 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. However, this specific endpoint — /api/v1/portfolios/4/holdings — is not listed on the site's main catalog and its exact response schema is undocumented. Based on the URL structure, it likely returns a list of asset holdings for a specific portfolio, but the precise fields and format are unknown.
The x402 challenge was successfully captured (HTTP 402 with valid accepts array), confirming the endpoint is live. Documentation on the site is extremely thin — the docs, pricing, API, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI spec, no example request/response, and no description of what the holdings response contains.
Capabilities
Use cases
- —Retrieving current holdings for a specific portfolio via micropayment
- —Integrating portfolio data into an agent workflow without API key management
- —Paying per-request for financial data using USDC on Base
Fit
Best for
- —Agents needing on-demand portfolio holdings data without subscription commitments
- —Developers prototyping x402 payment flows with a live endpoint
- —Low-volume consumers of portfolio data who prefer pay-per-call pricing
Not for
- —Users who need detailed API documentation or guaranteed response schemas before integrating
- —High-frequency data consumers who need bulk or streaming portfolio data at lower per-unit cost
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/4/holdings \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_proof>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI spec, no example request/response, and the endpoint is not listed in the provider's own catalog. The response schema is entirely unknown.
Warnings
- —No OpenAPI spec or schema documentation available
- —This specific endpoint (/api/v1/portfolios/4/holdings) is not listed on the provider's main API catalog — it may be unlisted, experimental, or deprecated
- —All documentation pages (docs, pricing, API, README) render only a 'Connect wallet' prompt with no substantive content
- —Response format and fields are completely unknown — no example response available
Citations
- —The endpoint returns HTTP 402 with x402 challenge advertising USDC on Base at maxAmountRequired 20000https://lowpaymentfee.com/api/v1/portfolios/4/holdings
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/4/holdings
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The provider's docs, pricing, API, and README pages show only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs