x402-gated portfolio transactions endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com provides access to portfolio transaction data via an x402 payment-gated POST request. The specific resource `/api/v1/portfolios/6/transactions` is part of a broader platform that offers dozens of pay-per-request APIs spanning data analytics, AI/ML inference, finance, crypto, and utility services — all settled on the Base network using USDC.
The x402 challenge captured from this endpoint indicates a maximum cost of 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this translates to $0.02 per request, consistent with the site's advertised flat pricing of $0.02/request across all endpoints. Payment is made via the x402 `exact` scheme with a 300-second timeout window. No API keys or rate limits are advertised; access is granted purely through the x402 payment header.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what the POST body should contain or what the response looks like. The endpoint name suggests it returns or creates transactions for portfolio ID 6, but the exact semantics (read vs. write), required fields, and response format are unknown.
Capabilities
Use cases
- —Retrieving or submitting portfolio transaction records via a single paid API call
- —Integrating pay-per-use financial data into agent workflows without managing API keys
- —Programmatic access to portfolio-level transaction data settled on Base L2
Fit
Best for
- —Agents needing keyless, pay-per-call access to portfolio transaction data
- —Developers experimenting with x402 payment-gated APIs on Base
- —Workflows that require on-demand financial transaction queries without subscriptions
Not for
- —Users who need detailed API documentation or schema guarantees before integrating
- —High-volume batch processing where per-request pricing may add up
- —Anyone requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/6/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 ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The purpose of this specific endpoint (portfolios/6/transactions) is unclear — it could be read or write. Effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, and README pages all show only 'Connect wallet'
- —No OpenAPI or request/response schema provided; request body format and response structure are unknown
- —The endpoint path references a hardcoded portfolio ID (6); unclear if this is a demo or a real resource
- —Purpose of the endpoint (read transactions vs. create transactions) is ambiguous
Citations
- —The x402 challenge specifies maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/6/transactions
- —The site advertises $0.02/request flat pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com