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 #87 via the x402 payment protocol. It is part of a broader platform (lowpaymentfee.com) that offers dozens of pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all gated behind x402 challenges settled in USDC on the Base network.
The specific endpoint `/api/v1/portfolios/87/transactions` returns an x402 challenge requiring a maximum of 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) per request. Payment is made via the "exact" scheme to the specified wallet address. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
Documentation on the site is extremely thin: the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema, and no explanation of what "portfolio transactions" data actually contains. The endpoint is live (402 challenge confirmed), but the lack of documentation makes it difficult to know what request body to send or what response to expect.
Capabilities
Use cases
- —Fetching or submitting portfolio transaction data with per-call USDC micropayments
- —Integrating pay-as-you-go financial data into agent workflows without API key management
- —Programmatic access to portfolio transaction records via x402 protocol
Fit
Best for
- —Agents or services that can settle x402 payments in USDC on Base
- —Developers wanting keyless, pay-per-request access to portfolio data
- —Automated workflows needing low-friction financial API access
Not for
- —Users who need detailed API documentation or response schemas before integrating
- —Applications requiring free or subscription-based access without per-call payments
- —Use cases needing high-throughput bulk data export (no documented batch support)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/87/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is zero documentation on request format, response schema, or what 'portfolio transactions' actually returns. No OpenAPI spec, no examples, and all doc pages are empty stubs. The listing is effectively a stub.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README all render only 'Connect wallet' with no content.
- —No request or response schema provided; callers cannot know what to send or expect back.
- —The specific purpose of 'portfolios/87/transactions' is unclear — it may be a demo or placeholder endpoint.
- —This endpoint path references a hardcoded portfolio ID (87), which may not be generally useful.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/87/transactions
- —The platform advertises $0.02 per request, no API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/87/transactions
- —Documentation pages (/docs, /api, /pricing, /README) contain only 'Connect wallet' with no technical contenthttps://lowpaymentfee.com/docs