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/23/transactions` accepts POST requests and is gated behind a per-call USDC payment on the Base network. The x402 challenge advertises a maximum cost of 20,000 base units of USDC (0.02 USD per request), consistent with the site-wide pricing of $0.02/request.
The hosting site lowpaymentfee.com offers a broad catalog of x402-gated APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all at the same $0.02/call price point. This particular endpoint appears to fall under a finance or portfolio management category, likely returning transaction records for a given portfolio (portfolio ID 23). However, no detailed documentation, request schema, or response schema is available from the crawled pages — the docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content.
Payment is settled in USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base mainnet using the x402 "exact" scheme. There are no API keys or rate limits advertised. The endpoint is live and returning a valid 402 challenge with x402Version 1.
Capabilities
Use cases
- —Fetching transaction records for a specific portfolio
- —Integrating portfolio transaction data into dashboards or analytics pipelines
- —Agent-driven portfolio monitoring with per-call payment
Fit
Best for
- —Agents needing on-demand portfolio transaction data without subscription commitments
- —Developers experimenting with x402 pay-per-call APIs on Base
- —Low-volume or sporadic access to portfolio transaction records
Not for
- —High-frequency bulk data retrieval where per-call costs add up
- —Users who need detailed API documentation or response schemas before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/23/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, confirming pricing and payment details. However, there is no documentation, no request/response schema, and no explanation of what data the endpoint actually returns. The docs pages are empty (wallet-connect only). This is effectively a stub listing with confirmed liveness.
Warnings
- —No API documentation available — docs, pricing, and README pages all return only a wallet-connect prompt with no content.
- —No request or response schema provided; the purpose and data format of portfolio transactions must be inferred.
- —Portfolio ID 23 is hardcoded in the endpoint path; unclear if other portfolio IDs are accessible or how they are obtained.
- —The site lists many API categories but none of the crawled pages provide substantive technical detail.
Citations
- —The endpoint returns a 402 challenge with x402Version 1, maxAmountRequired 20000 base units of USDC on Base network.https://lowpaymentfee.com/api/v1/portfolios/23/transactions
- —Site-wide pricing is $0.02 per request with no API keys, no rate limits, and instant access on the Base network.https://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base.https://lowpaymentfee.com/api/v1/portfolios/23/transactions