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/31/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 20000 base units, which at 6 decimals equals $0.02 USD per call. The endpoint uses the "exact" payment scheme with a 300-second timeout. No OpenAPI schema or detailed documentation was found beyond the landing page listing; the docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content.
Because this specific endpoint path references a hardcoded portfolio ID (31), it likely returns transaction records for that particular portfolio. Without request/response schema documentation, the exact input parameters and output format are unknown. The platform appears to be a demonstration or early-stage x402 API marketplace with many listed endpoints, but documentation is essentially absent.
Capabilities
Use cases
- —Retrieving transaction history for a specific portfolio via micropayment
- —Integrating pay-per-call portfolio data into agent workflows
- —Accessing financial transaction data without API key registration
Fit
Best for
- —Agents needing on-demand portfolio transaction data without signup
- —Developers experimenting with x402 payment protocol on Base
- —Low-volume, pay-as-you-go financial data access
Not for
- —High-volume bulk transaction data retrieval (no documented rate limits but no SLA either)
- —Users needing detailed API documentation or guaranteed schema stability
- —Accessing arbitrary portfolio IDs (endpoint is hardcoded to portfolio 31)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/31/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, but there is no OpenAPI schema, no request/response documentation, and all doc pages return only a wallet-connect prompt. The endpoint path is hardcoded to a single portfolio ID with no explanation of what data it returns.
Warnings
- —No API documentation available — docs, pricing, and README pages all show only 'Connect wallet' with no content
- —No request or response schema provided; input parameters and output format are unknown
- —Endpoint path is hardcoded to portfolio ID 31; unclear if other portfolio IDs are accessible
- —Platform appears early-stage or demonstrative; no SLA or reliability guarantees documented
Citations
- —Endpoint returns HTTP 402 with x402 challenge advertising maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/31/transactions
- —Platform pricing is $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/31/transactions