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/100/transactions` is part of a broader platform that offers dozens of pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all settled on the Base network using USDC.
The x402 challenge confirms the endpoint is live and accepts exact-scheme payments in USDC (contract 0x8335…2913 on Base) with a maximum cost of $0.02 per request (20,000 base units at 6 decimals). No API keys or rate limits are advertised; callers simply attach an X-PAYMENT header with a valid x402 payment proof. The payment timeout is 300 seconds.
Documentation is extremely sparse. The crawled /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 purpose — whether it retrieves, creates, or manages portfolio transactions — must be inferred from the URL path alone. Prospective callers should expect to experiment or contact the provider for integration details.
Capabilities
Use cases
- —Retrieving or submitting portfolio transaction records via a pay-per-call model
- —Integrating portfolio data into automated trading or analytics pipelines
- —Demonstrating x402 payment flows for agent-to-agent commerce on Base
Fit
Best for
- —Developers experimenting with x402 payment-gated APIs
- —Agents needing on-demand portfolio transaction data without API key management
- —Low-volume, pay-as-you-go access to financial data endpoints
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who need bulk pricing or subscription plans
- —Anyone requiring non-USDC or non-Base-network payment settlement
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/100/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is confirmed live via a valid x402 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no request/response examples, and all documentation pages are empty stubs. The actual functionality of this specific transactions endpoint is unknown beyond what the URL implies.
Warnings
- —No OpenAPI or schema documentation available — request and response formats are entirely unknown
- —All documentation pages (/docs, /api, /pricing, /README) returned only 'Connect wallet' with no content
- —The specific purpose of /api/v1/portfolios/100/transactions (read vs. write, required fields) cannot be confirmed from available material
- —The portfolio ID '100' is hardcoded in the URL; it is unclear whether other portfolio IDs are supported
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/100/transactions
- —The platform advertises $0.02 per request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/100/transactions