x402-gated portfolio transactions endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to portfolio transaction data via a POST request to `/api/v1/portfolios/46/transactions`. It is part of a broader platform (lowpaymentfee.com) that offers a variety of x402-gated APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all settled on the Base network using USDC.
The specific endpoint probed here charges up to $0.02 per request (maxAmountRequired of 20,000 base units of USDC, which has 6 decimals = $0.02). Payment is handled via the x402 protocol: callers receive a 402 challenge with payment details, attach an `X-PAYMENT` header with a signed payment, and the server fulfills the request. No API keys or accounts are required; access is instant once payment is provided. The platform advertises no rate limits and no minimum commitments.
Documentation on the site is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no detailed description of what the `/portfolios/46/transactions` endpoint actually returns. The endpoint appears to be live (402 challenge captured successfully), but the lack of documentation makes it difficult to determine the exact input format or output structure.
Capabilities
Use cases
- —Retrieving transaction records for a specific portfolio
- —Integrating portfolio transaction data into automated trading or analytics pipelines
- —Agent-driven portfolio monitoring with per-call micropayments
Fit
Best for
- —Developers wanting keyless, pay-per-call access to portfolio transaction data
- —AI agents that can settle USDC payments on Base via x402
- —Users who prefer no-subscription, usage-based API pricing
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —Applications requiring non-crypto payment methods
- —High-volume batch retrieval where per-call pricing may add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/46/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no request/response examples, and all documentation pages return only a wallet-connect prompt. The purpose of this specific endpoint (portfolios/46/transactions) is not explained anywhere.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or request/response schema provided; input and output formats are unknown.
- —The endpoint path references a hardcoded portfolio ID (46), which may indicate a demo or placeholder rather than a general-purpose API.
- —The broader platform lists many API categories but it is unclear which are actually functional.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base network.https://lowpaymentfee.com/api/v1/portfolios/46/transactions
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on the Base network.https://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 is used for payment on Base.https://lowpaymentfee.com/api/v1/portfolios/46/transactions