x402-gated portfolio endpoint on Base, pay $0.02 per request in USDC — no API keys required.
What it does
This endpoint at lowpaymentfee.com provides a "Premium API Access" resource at `/api/v1/portfolios/81` via the x402 payment protocol. It is one of many endpoints offered by the lowpaymentfee.com platform, which hosts a variety of data, AI, finance, and utility APIs all priced at $0.02 per request, settled in USDC on the Base network.
The specific `/api/v1/portfolios/81` endpoint accepts POST requests and returns JSON. Payment is handled inline via the x402 protocol: callers send an `X-PAYMENT` header containing a signed payment of up to 20,000 base units of USDC (i.e., $0.02, since USDC uses 6 decimals) to the provider's address on Base. There are no API keys, no rate limits, and no subscription commitments — each call is independently paid.
The broader lowpaymentfee.com platform also offers endpoints for analytics/metrics, reports, data export, insights, sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02/request price point. However, the specific data returned by `/api/v1/portfolios/81` is not documented in the crawled material; the endpoint name suggests portfolio-related data but no schema or example response was found.
Capabilities
Use cases
- —Fetching portfolio data on a pay-per-request basis without managing API keys or subscriptions
- —Integrating low-cost data endpoints into autonomous agents that settle payments in USDC on Base
- —Accessing financial or portfolio information with instant, permissionless access
Fit
Best for
- —Agents or developers who want keyless, pay-per-call API access
- —Users who prefer crypto-native micropayments over traditional billing
- —Low-volume or sporadic consumers who don't want subscription commitments
Not for
- —High-volume consumers who need bulk pricing or enterprise SLAs
- —Users who cannot transact in USDC on the Base network
- —Anyone needing detailed documentation or guaranteed response schemas before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/81 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no documentation on what `/api/v1/portfolios/81` actually returns — no response schema, no example, and no description beyond the generic 'Premium API Access' label. The docs, pricing, and API pages all returned only 'Connect wallet' with no useful content.
Warnings
- —No documentation found for the specific /api/v1/portfolios/81 endpoint — unclear what data it returns
- —All documentation pages (docs, api, pricing, README) returned only 'Connect wallet' with no substantive content
- —No OpenAPI spec or response schema available
- —The endpoint path suggests portfolio data but the exact nature and structure of the response is unknown
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/portfolios/81
- —All endpoints on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com