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/48/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 advertises a `maxAmountRequired` of 20,000 base units, which at 6 decimals equals $0.02 USD per call. The payment scheme is "exact" and the timeout is 300 seconds. No OpenAPI schema, detailed documentation, or example request/response bodies were found during crawling — the docs, pricing, and API pages all returned only a "Connect wallet" prompt with no further content.
Because the specific endpoint path references a hardcoded portfolio ID (48), it is unclear whether this is a demo/sample portfolio or whether other portfolio IDs are supported. The endpoint is confirmed live (HTTP 402 challenge returned successfully), but the lack of documentation about request body format, response schema, and the meaning of "transactions" in this context limits practical usability without experimentation.
Capabilities
Use cases
- —Fetching transaction records for a portfolio via a single paid API call
- —Integrating pay-per-use financial data into agent workflows without API key management
- —Programmatic access to portfolio transaction data settled in USDC on Base
Fit
Best for
- —Agents or bots that need on-demand portfolio transaction data without subscription overhead
- —Developers experimenting with x402 payment-gated APIs
- —Low-volume, pay-as-you-go financial data consumers
Not for
- —High-volume bulk transaction data retrieval (no documented batch support)
- —Users who need detailed API documentation or guaranteed SLAs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/48/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI schema, no request/response examples, and no meaningful documentation — all doc pages returned only 'Connect wallet'. The specific portfolio ID (48) in the URL is unexplained.
Warnings
- —No API documentation available — all doc pages return only 'Connect wallet' with no content
- —No request body schema or response schema documented
- —Hardcoded portfolio ID (48) in the endpoint path — unclear if other IDs are supported or what this portfolio represents
- —No OpenAPI spec or ai-plugin manifest found
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/48/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 Base networkhttps://lowpaymentfee.com/api/v1/portfolios/48/transactions