x402-gated portfolio transactions endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com exposes a POST-based transactions API for portfolio #51, gated behind the x402 payment protocol. It accepts USDC payments on the Base network at $0.02 per request (20,000 base units of USDC with 6 decimals). The x402 challenge is live and returns a standard 402 response with payment parameters including the payTo address and asset contract (USDC on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913).
The hosting site lowpaymentfee.com advertises a broad catalog of x402-gated APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $0.02 per request with no API keys, no rate limits, and no commitments. However, the specific endpoint being listed here (/api/v1/portfolios/51/transactions) is not explicitly described on the site's landing page among the advertised categories. Its exact input schema and response format are undocumented; the x402 challenge only confirms it accepts HTTP POST and returns application/json.
Because there is no OpenAPI spec, no request/response examples, and no documentation beyond the generic site landing page, the actual functionality of this particular endpoint remains unclear. It may relate to the Finance & Web3 category given the "portfolios/transactions" path, but this is inference only. The site's docs, pricing, and API pages all render only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Submitting or retrieving portfolio transaction records via a pay-per-call model
- —Integrating x402-gated financial data into agent workflows
- —Programmatic access to transaction data without API key management
Fit
Best for
- —Agents or services that can handle x402 payment flows on Base
- —Users who want keyless, pay-as-you-go API access
- —Web3-native applications needing on-chain payment settlement
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —Applications requiring free or subscription-based access without per-call crypto payments
- —Use cases needing well-documented request/response schemas
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/51/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and confirms pricing and payment details, but there is zero documentation on what this specific endpoint does, what inputs it expects, or what it returns. The site's docs pages are empty. This is effectively a stub listing.
Warnings
- —No OpenAPI spec or request/response schema available for this endpoint
- —The /api/v1/portfolios/51/transactions path is not listed among the site's advertised APIs — its purpose is unclear
- —All documentation pages (docs, pricing, API, README) render only a 'Connect wallet' prompt with no useful content
- —Exact functionality of this endpoint is inferred from the URL path only
Citations
- —The x402 challenge returns maxAmountRequired of 20000 in USDC (6 decimals) on Base, equaling $0.02 per requesthttps://lowpaymentfee.com/api/v1/portfolios/51/transactions
- —The site advertises $0.02/request pricing with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/51/transactions
- —Documentation pages render only a 'Connect wallet' prompt with no additional contenthttps://lowpaymentfee.com/docs