Portfolio performance data via x402 micropayment on Base network, $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com returns portfolio performance data for a specific portfolio (ID 40) behind an x402 paywall. The endpoint accepts POST requests and responds with JSON. Payment is settled on the Base network using USDC (contract 0x8335…2913) with an exact-scheme micropayment of 20,000 base units, which equals $0.02 per request (USDC uses 6 decimals).
The provider site lowpaymentfee.com hosts a broad collection of x402-gated APIs spanning data analytics, AI/ML inference, finance/Web3, and infrastructure utilities — all priced at $0.02 per call. This particular endpoint falls under the finance category. No API keys or rate limits are advertised; access is granted purely via the x402 payment header. The x402 challenge specifies a maximum timeout of 300 seconds.
Documentation is extremely sparse. The docs, pricing, and API pages all render only a "Connect wallet" prompt with no additional technical detail. There is no OpenAPI spec, no request/response schema, and no example payloads available. The endpoint path suggests it returns performance metrics for portfolio #40, but the exact request body format and response structure are unknown.
Capabilities
Use cases
- —Retrieve performance metrics for a specific investment portfolio
- —Integrate portfolio performance data into dashboards or trading bots
- —Agent-driven portfolio monitoring with per-call micropayments
Fit
Best for
- —Developers needing on-demand portfolio performance data without subscriptions
- —AI agents that can settle x402 payments on Base
- —Applications requiring low-cost, keyless API access to financial data
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —Bulk historical portfolio data retrieval (no evidence of batch support)
- —Non-crypto-native clients who cannot settle USDC payments on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/40/performance \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (returns a valid x402 402 challenge) and pricing is clear at $0.02/request in USDC on Base. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page, and no example payloads. The specific purpose of portfolio 40 is unexplained.
Warnings
- —No OpenAPI or schema documentation available — request body format and response structure are completely unknown
- —Docs, pricing, and API pages render only 'Connect wallet' with no technical content
- —The endpoint is hardcoded to portfolio ID 40; unclear if other portfolio IDs are available or what this portfolio represents
- —No information on data freshness, update frequency, or data source
Citations
- —The x402 challenge returns maxAmountRequired of 20000 in USDC (6 decimals) on Base network, equaling $0.02 per requesthttps://lowpaymentfee.com/api/v1/portfolios/40/performance
- —The provider advertises $0.02/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/40/performance