x402-gated portfolio transactions endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to portfolio transaction data via a POST request to `/api/v1/portfolios/73/transactions`. It is part of a broader platform (lowpaymentfee.com) that offers a variety of x402-protocol pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $0.02 per request settled in USDC on the Base network.
The specific endpoint probed here returns an x402 challenge (HTTP 402) requiring an `X-PAYMENT` header with an exact-scheme payment of up to 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, 20,000 base units equals $0.02. Payment is sent to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` with a 300-second timeout. The endpoint accepts `application/json` and uses POST.
Documentation beyond the landing page is extremely sparse — 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 example payloads available. The exact structure of the POST body and the shape of the transaction data returned are unknown. The platform advertises no API keys, no rate limits, and instant access, but these claims cannot be independently verified from the crawl material.
Capabilities
Use cases
- —Fetching transaction history for a specific portfolio via automated agents
- —Integrating portfolio transaction data into dashboards or analytics pipelines
- —Agent-driven portfolio monitoring with per-call USDC micropayments
Fit
Best for
- —Developers wanting keyless, pay-per-use portfolio transaction data
- —AI agents that can settle x402 payments on Base in USDC
- —Prototyping financial data integrations without subscription commitments
Not for
- —Users needing detailed API documentation or request/response schemas before integrating
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/73/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is no OpenAPI spec, no request/response schema, no documentation, and no examples. The purpose of this specific endpoint (portfolios/73/transactions) is unclear beyond its URL path. Effectively a stub listing.
Warnings
- —No OpenAPI or schema available — request body and response format are completely unknown
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content
- —The endpoint path references a hardcoded portfolio ID (73); it is unclear whether other portfolio IDs are supported or what this portfolio represents
- —Platform claims 'no rate limits' but this cannot be verified
Citations
- —The endpoint returns an x402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/73/transactions
- —Platform advertises $0.02 per request, no API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/73/transactions