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 a POST request to `/api/v1/portfolios/13/transactions`. It is part of a broader platform (lowpaymentfee.com) that offers dozens of x402-gated API endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities.
The specific endpoint probed here returns an x402 challenge requesting payment in USDC on the Base network. The maximum amount required is 20,000 base units of USDC (6 decimals), which equals $0.02 per request. The platform advertises uniform $0.02/request pricing across all its endpoints, with no API keys, no rate limits, and no minimum commitments — payment is handled entirely via the x402 protocol's `X-PAYMENT` header.
Documentation beyond the landing page is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what fields the transactions endpoint accepts or returns. The endpoint is confirmed live (402 challenge captured), but the lack of documentation makes it difficult to determine the exact input format or output structure.
Capabilities
Use cases
- —Retrieving transaction records for a specific portfolio
- —Integrating portfolio transaction data into automated trading or analytics pipelines
- —Agent-driven portfolio monitoring with per-call micropayments
Fit
Best for
- —Developers wanting keyless, pay-per-use access to portfolio transaction data
- —AI agents that can settle x402 payments on Base in USDC
- —Users who prefer micropayment-based API access without subscriptions
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or subscription plans
- —Anyone needing non-USDC or non-Base payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/13/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live via a valid x402 402 challenge, and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no request/response examples, and all documentation pages are empty beyond a wallet-connect prompt. The specific purpose of the portfolios/13/transactions endpoint is only inferable from the URL path.
Warnings
- —No OpenAPI schema or API documentation available — all doc pages render only 'Connect wallet'
- —No request body schema or response examples provided; input/output format is unknown
- —The endpoint targets a hardcoded portfolio ID (13); unclear if other portfolio IDs are accessible
- —Platform appears to be a generic demo or showcase site with many listed endpoints but no substantive docs
Citations
- —The endpoint returns an x402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/13/transactions
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/13/transactions