x402-gated portfolio transactions endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com provides access to portfolio transaction data via the x402 payment protocol. The specific resource `/api/v1/portfolios/83/transactions` accepts POST requests and charges up to $0.02 per call in USDC on the Base network. Payment is handled entirely through the x402 challenge-response flow — no API keys or accounts are required.
The hosting site lowpaymentfee.com offers a broad catalog of x402-gated APIs spanning data analytics, AI/ML inference, finance/Web3 data, and utility services, all priced at $0.02 per request. However, this particular endpoint (`/portfolios/83/transactions`) is not explicitly listed on the site's landing page among the advertised categories. Its description is simply "Premium API Access," and no further documentation, request schema, or response schema is available from the crawled pages (docs, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content).
Without documentation on what fields the POST body expects or what the response contains, the exact functionality is unclear. The endpoint appears to relate to transactions within a specific portfolio (ID 83), but whether this is a read operation disguised as POST, a transaction-creation endpoint, or something else cannot be confirmed from available material. The x402 challenge is live and well-formed, confirming the endpoint is operational.
Capabilities
Use cases
- —Fetching or creating portfolio transaction records via a single paid API call
- —Integrating pay-per-use financial data into agent workflows without API key management
- —Programmatic access to portfolio data settled on Base L2 with USDC
Fit
Best for
- —Agents or applications that need keyless, pay-per-call access to portfolio transaction data
- —Developers experimenting with x402 payment protocol integrations
- —Workflows requiring low-friction micropayment-gated API access on Base
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume use cases where $0.02/request adds up significantly without bulk discounts
- —Anyone needing non-USDC or non-Base payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/83/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and well-formed, confirming the endpoint is operational at $0.02/call in USDC on Base. However, there is no documentation, no request/response schema, and the endpoint's specific purpose (portfolio 83 transactions) is unexplained. Docs, pricing, and README pages returned no useful content.
Warnings
- —No request or response schema available — POST body format is unknown
- —Endpoint /api/v1/portfolios/83/transactions is not listed among the site's advertised APIs
- —All documentation pages (docs, pricing, README) returned only 'Connect wallet' with no content
- —The specific portfolio ID (83) is hardcoded in the path with no explanation of what it represents
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units (USDC, 6 decimals = $0.02) on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/83/transactions
- —The site advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/83/transactions