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/22/transactions` accepts POST requests and charges up to $0.02 per call in USDC on the Base network. Payment is handled inline via the x402 challenge-response mechanism — no API keys, accounts, or rate limits are required.
The endpoint is part of a broader platform (lowpaymentfee.com) that offers a variety of pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3 data, and utility services, all priced at $0.02 per request. However, the specific endpoint listed here targets portfolio transactions (portfolio ID 22). The crawl material does not document the request body schema, expected fields, or response format for this particular endpoint, so the exact data returned is unclear.
Payment settles in USDC (contract 0x8335…2913) on Base to address 0x1A2B…85F3, with a maximum timeout of 300 seconds. The x402 challenge was successfully captured (HTTP 402), confirming the endpoint is live and operational.
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
- —Developers needing on-demand portfolio transaction data without subscription commitments
- —AI agents that can settle USDC payments on Base via x402
- —Low-volume or sporadic access to financial transaction records
Not for
- —High-frequency bulk data retrieval where per-call pricing becomes expensive
- —Users who need detailed API documentation before integrating
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/22/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_token>"Endpoint
Quality
The x402 challenge is live and confirms pricing and payment details, but there is no documentation of the request body schema, response format, or what 'portfolio 22 transactions' actually contains. The docs, pricing, and API pages all returned only a 'Connect wallet' stub with no useful content.
Warnings
- —No request body schema or response schema documented — the exact data this endpoint returns is unknown.
- —The endpoint targets a hardcoded portfolio ID (22); it is unclear whether other portfolio IDs are available or how they are created.
- —Documentation pages (/docs, /api, /pricing, /README) returned no meaningful content beyond 'Connect wallet'.
- —The platform lists many API categories (AI, analytics, finance, utilities) all at $0.02 — it is unclear which are fully functional vs. placeholder.
Citations
- —Endpoint returns HTTP 402 with x402 challenge, confirming it is livehttps://lowpaymentfee.com/api/v1/portfolios/22/transactions
- —Max amount required is 20000 base units of USDC (6 decimals) = $0.02 per requesthttps://lowpaymentfee.com/api/v1/portfolios/22/transactions
- —Payment settles in USDC on Base network to 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3https://lowpaymentfee.com/api/v1/portfolios/22/transactions
- —Platform advertises $0.02/request, no API keys, no rate limits, instant access on Basehttps://lowpaymentfee.com