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/49/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 per call. The endpoint uses the "exact" payment scheme with a 300-second timeout. 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 this specific endpoint path references a hardcoded portfolio ID (49), it is unclear whether this is a demo/sample portfolio or whether other portfolio IDs are supported. The lack of input/output schema documentation means callers will need to experiment or contact the provider to understand the expected POST body and response format.
Capabilities
Use cases
- —Fetching transaction history for a portfolio via a single paid API call
- —Integrating portfolio transaction data into an agent workflow without managing API keys
- —Programmatic access to financial transaction records settled via USDC on Base
Fit
Best for
- —Agents or bots that need on-demand portfolio transaction data without subscription overhead
- —Developers exploring x402 pay-per-call patterns on Base
- —Low-volume consumers who prefer per-request billing over monthly plans
Not for
- —High-volume consumers needing bulk transaction exports at lower per-unit cost
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/49/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 documentation beyond a wallet-connect prompt, no example request/response, and the endpoint path is hardcoded to portfolio ID 49 with no explanation. Effectively a stub listing.
Warnings
- —No OpenAPI or input/output schema available — request body format is unknown
- —Documentation pages (/docs, /api, /pricing, /README) all return only 'Connect wallet' with no usable content
- —Endpoint path is hardcoded to portfolio ID 49; unclear if other portfolio IDs are supported
- —No rate limit or SLA information provided
Citations
- —The x402 challenge advertises maxAmountRequired of 20000 base units in USDC on Base network with 300-second timeouthttps://lowpaymentfee.com/api/v1/portfolios/49/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 is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/49/transactions