x402-gated portfolio transactions endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com exposes a POST-based API for portfolio transactions at `/api/v1/portfolios/88/transactions`. It is part of a broader platform (lowpaymentfee.com) that offers dozens of x402-gated endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities. All endpoints on the platform use the x402 payment protocol on the Base network, settling in USDC.
The specific endpoint probed (`/api/v1/portfolios/88/transactions`) returns a valid x402 challenge with a maximum amount of 20,000 base units of USDC (6 decimals), which equals $0.02 per request. This is consistent with the platform's advertised flat pricing of $0.02 per request across all endpoints. The platform advertises no API keys, no rate limits, and instant access — payment is the only authentication mechanism.
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 schema, no request/response examples, and no description of what the portfolio transactions endpoint actually accepts or returns. The endpoint's `outputSchema` indicates it expects an HTTP POST request, but no input or output field definitions are provided. Without documentation, the actual functionality of this endpoint is unclear — it could involve creating, listing, or managing transactions within a portfolio, but this is speculative.
Capabilities
Use cases
- —Submitting or recording transactions against a portfolio via a pay-per-call model
- —Integrating portfolio transaction data into automated trading or accounting workflows
- —Agent-driven portfolio management where each API call is settled in USDC on Base
Fit
Best for
- —Developers wanting keyless, pay-per-request portfolio transaction access
- —AI agents that can settle x402 payments on Base in USDC
- —Prototyping financial workflows without subscription commitments
Not for
- —Users who need detailed API documentation or schemas before integrating
- —High-volume use cases where $0.02 per request adds up significantly
- —Anyone needing non-USDC or non-Base payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/88/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no documentation beyond a wallet-connect prompt, no request/response examples, and no description of what the portfolio transactions endpoint actually does. This is effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, and README pages all show only 'Connect wallet'
- —No OpenAPI or input/output schema provided for this endpoint
- —The actual functionality of /api/v1/portfolios/88/transactions is unknown — the description 'Premium API Access' is generic
- —The portfolio ID '88' is hardcoded in the URL; unclear if other portfolio IDs are supported
Citations
- —The platform advertises $0.02 per request with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —The x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/portfolios/88/transactions
- —Docs, API, pricing, and README pages render only a 'Connect wallet' prompt with no further contenthttps://lowpaymentfee.com/docs