Pay-per-call portfolio transactions endpoint on Base via x402 (USDC, $0.02/request).
What it does
This x402-enabled endpoint at lowpaymentfee.com provides access to portfolio transaction data at the path `/api/v1/portfolios/84/transactions`. It accepts POST requests and is paid per-call using USDC on the Base network. The x402 challenge confirms the endpoint is live, advertising a max amount of 20,000 base units of USDC (0.02 USD per request, since USDC uses 6 decimals). Payment is settled on-chain to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using the "exact" payment scheme.
The provider site (lowpaymentfee.com) hosts a broad catalog of x402 APIs spanning data & analytics, AI/ML inference, finance/Web3, and infrastructure utilities — all priced at $0.02 per request with no API keys, no rate limits, and no minimum commitments. However, this specific endpoint (`/portfolios/84/transactions`) is not explicitly listed on the provider's landing page among the advertised APIs, and no documentation, request schema, or response schema is available for it. The crawled docs, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content.
Because there is no OpenAPI spec, no request/response schema, and no documentation describing what this endpoint actually returns or what POST body it expects, the listing is largely a stub. The endpoint is confirmed live (402 challenge captured), but its exact functionality — whether it returns transaction history for a specific portfolio, creates new transactions, or something else — cannot be determined from available material.
Capabilities
Use cases
- —Fetching or submitting portfolio transaction data via a single paid API call
- —Integrating on-chain micropayment-gated financial data into agent workflows
- —Programmatic access to portfolio-level transaction records without API key management
Fit
Best for
- —Agents or developers who want keyless, pay-per-call access to portfolio transaction data
- —Use cases requiring on-chain USDC micropayments on Base for API access
- —Scenarios where no subscription or rate-limit management is desired
Not for
- —Users who need detailed API documentation or guaranteed response schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or subscription plans
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/84/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, but there is no documentation, no request/response schema, no OpenAPI spec, and the specific endpoint path is not listed on the provider's own landing page. Effectively a stub with only pricing and liveness confirmed.
Warnings
- —No request or response schema available — POST body format is unknown
- —This specific endpoint (/api/v1/portfolios/84/transactions) is not listed among the provider's advertised APIs
- —All documentation pages (docs, pricing, README, api) returned only 'Connect wallet' with no content
- —The hardcoded portfolio ID '84' in the path suggests this may be a specific resource rather than a general-purpose API
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/84/transactions
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/84/transactions
- —Provider advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Provider landing page lists APIs in categories: Data & Analytics, AI & ML, Finance & Web3, Infrastructure — but does not list /portfolios/84/transactionshttps://lowpaymentfee.com