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 via a POST request to `/api/v1/portfolios/70/transactions`. It is part of a broader platform offering data & analytics, AI/ML inference, finance/Web3, and infrastructure utility APIs, all priced at $0.02 per request with no API keys, no rate limits, and no commitments required.
Payment is settled on the Base network using USDC (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`). The x402 challenge specifies a `maxAmountRequired` of 20000 base units, which at 6 decimals equals $0.02 per call. The endpoint uses the "exact" payment scheme with a 300-second timeout. No OpenAPI schema or detailed documentation was found for this specific endpoint beyond the x402 challenge metadata.
The specific endpoint listed here (`/portfolios/70/transactions`) appears to be a fixed portfolio ID (70). Without further documentation it is unclear whether this is a demo portfolio, a shared dataset, or a user-specific resource. The broader site advertises many endpoints across categories but crawled documentation pages returned only wallet-connect prompts with no substantive content.
Capabilities
Use cases
- —Fetching transaction history for a specific portfolio via a single paid API call
- —Integrating portfolio transaction data into automated trading or analytics pipelines
- —Agent-driven portfolio monitoring with per-request micropayments
Fit
Best for
- —Developers wanting keyless, pay-per-use portfolio transaction data
- —AI agents that can settle x402 payments on Base with USDC
- —Prototyping financial data integrations without subscription commitments
Not for
- —Users needing bulk historical data exports at scale (no documented batch mode)
- —Anyone requiring detailed API documentation or OpenAPI specs before integration
- —Use cases requiring portfolio IDs other than 70 (unclear if other IDs are supported)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/70/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no request/response examples, and the documentation pages are empty beyond wallet-connect prompts. The specific purpose of portfolio 70 transactions is undocumented.
Warnings
- —No OpenAPI or request/response schema available for this endpoint
- —Documentation pages (/docs, /api, /pricing, /README) returned no substantive content
- —The portfolio ID '70' is hardcoded in the endpoint path with no explanation of what it represents
- —No information on what fields the POST body accepts or what the response contains
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units in USDC on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/70/transactions
- —All APIs on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/70/transactions