x402-gated portfolio transactions endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com exposes a POST-based transactions API for portfolio #77 via the x402 payment protocol. It is part of a broader platform (lowpaymentfee.com) that offers dozens of pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all gated behind x402 challenges settled in USDC on the Base network.
The specific endpoint `/api/v1/portfolios/77/transactions` accepts POST requests and charges up to $0.02 per call (maxAmountRequired of 20,000 base units of USDC, which has 6 decimals = $0.02). Payment is made via the x402 exact scheme to the specified payTo address. No API keys or rate limits are advertised; access is granted purely through the x402 payment header.
Documentation on the site is extremely sparse — the docs, pricing, API, 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 a successful call returns. The endpoint name suggests it deals with financial portfolio transactions, but without documentation it is unclear whether this creates, retrieves, or manages transactions. The platform's landing page groups its APIs into categories (Data & Analytics, AI & ML, Finance & Web3, Infrastructure), but this specific portfolio transactions endpoint is not listed among them, making its purpose and capabilities uncertain.
Capabilities
Use cases
- —Submitting or retrieving portfolio transaction data via a pay-per-call model
- —Integrating x402-compatible agents with financial portfolio endpoints
- —Programmatic access to portfolio transactions without API key management
Fit
Best for
- —Developers building x402-compatible payment agents
- —Users who want keyless, pay-per-request API access
- —Applications needing Base-network USDC micropayment settlement
Not for
- —Users who need detailed API documentation or schemas before integrating
- —High-volume use cases where per-request pricing may add up without volume discounts
- —Anyone requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/77/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, confirming it exists and accepts payments. However, there is no documentation, no OpenAPI spec, no request/response schema, and no examples. The endpoint's specific purpose (portfolio #77 transactions) is not explained anywhere on the site. This is effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, API, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or request/response schema provided; request body and response format are completely unknown.
- —This specific endpoint (/api/v1/portfolios/77/transactions) is not listed on the provider's landing page among their advertised APIs.
- —The purpose of 'portfolios/77/transactions' is unclear — it may be a demo or placeholder endpoint.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Base network.https://lowpaymentfee.com/api/v1/portfolios/77/transactions
- —The platform advertises $0.02 per request pricing with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with 6 decimals, making 20000 base units = $0.02.https://lowpaymentfee.com