x402-gated portfolio endpoint on Base, pay-per-request with USDC.
What it does
This endpoint at `/api/v1/portfolios/26` is part of the lowpaymentfee.com platform, which offers a collection of x402-protocol pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities. The specific `/portfolios/26` resource is listed under "Premium API Access" and returns JSON via POST. Payment is settled on the Base network using USDC (contract `0x8335…2913`) through the x402 exact-payment scheme.
The x402 challenge confirms the endpoint is live and requires a maximum of 20,000 base units of USDC per request. Since USDC uses 6 decimals, this translates to $0.02 per call — consistent with the site's uniform $0.02/request pricing across all endpoints. No API keys are required; access is granted purely through the x402 payment header. The platform advertises no rate limits and instant access.
Documentation is extremely sparse. The `/docs`, `/api`, `/pricing`, and `/README` pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no description of what the `/portfolios/26` resource actually returns. The endpoint name "Premium API Access" is generic and does not clarify the data served. Without documentation or example responses, the actual payload and use case of this specific endpoint remain unclear.
Capabilities
Use cases
- —Fetching portfolio data (specifics unknown) via a single paid POST request
- —Integrating pay-per-call data access into agent workflows without API key management
- —Programmatic access to a premium resource settled on Base L2 with USDC
Fit
Best for
- —Agents or developers who want keyless, pay-per-request API access
- —Users already holding USDC on Base who need low-friction data endpoints
- —Exploring x402-protocol integrations with minimal commitment
Not for
- —Users who need detailed documentation or guaranteed SLAs before integrating
- —Anyone requiring free or subscription-based access rather than per-call payments
- —Use cases needing clearly defined response schemas upfront
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/26 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02/request in USDC on Base), but there is no documentation, no OpenAPI spec, no request/response schema, and no description of what the /portfolios/26 resource actually returns. The endpoint is effectively a stub listing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README pages all show only 'Connect wallet' with no content
- —No OpenAPI or schema definition for request or response payloads
- —The purpose and data returned by /api/v1/portfolios/26 is completely undocumented
- —No examples of successful responses are available
Citations
- —The endpoint returns HTTP 402 with an x402 challenge requiring USDC payment on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/26
- —maxAmountRequired is 20000 base units of USDC (6 decimals) = $0.02 per requesthttps://lowpaymentfee.com/api/v1/portfolios/26
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/26