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/99/transactions` appears to be part of a broader finance/Web3 API suite offered by the provider. Payment is settled on the Base network using USDC (contract 0x8335…2913) at $0.02 per request.
The provider's landing page advertises a wide catalog of pay-per-call APIs spanning data & analytics, AI/ML inference, finance & Web3, and infrastructure utilities — all priced at $0.02 per request with no API keys, no rate limits, and no commitments. However, the specific endpoint being listed here targets portfolio transactions, which falls under the finance category. The x402 challenge was successfully captured (HTTP 402 with a valid accepts payload), confirming the endpoint is live.
Documentation is extremely sparse. The docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what fields the transactions endpoint accepts or returns. The endpoint's actual behavior and data model must be discovered by making an authenticated (paid) request.
Capabilities
Use cases
- —Retrieving transaction history for a specific portfolio
- —Integrating portfolio transaction data into dashboards or analytics pipelines
- —Automated agents querying financial transaction records with per-call USDC payments
Fit
Best for
- —Developers who want keyless, pay-per-call access to portfolio transaction data
- —AI agents that can settle x402 payments on Base with USDC
- —Projects needing on-demand financial data without subscription commitments
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would prefer bulk pricing or subscriptions
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/99/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02/request in USDC on Base). However, there is no documentation, no OpenAPI schema, no request/response examples, and the docs pages are empty. The actual data returned by this endpoint is unknown, making this effectively a stub listing.
Warnings
- —No OpenAPI schema or request/response documentation available
- —All doc pages (docs, API, pricing, README) return only 'Connect wallet' with no content
- —The specific data model and accepted parameters for /api/v1/portfolios/99/transactions are unknown
- —Portfolio ID '99' is hardcoded in the URL — unclear if this is a demo or a real portfolio
Citations
- —The endpoint returns a valid x402 challenge with USDC on Base network at maxAmountRequired 20000 (= $0.02)https://lowpaymentfee.com/api/v1/portfolios/99/transactions
- —The provider advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/99/transactions