Portfolio performance data via x402 micropayment on Base network, $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides portfolio performance data for a specific portfolio (ID 13) behind an x402 paywall. The endpoint accepts POST requests and returns JSON. Payment is settled on the Base network using USDC (contract 0x8335…2913) with a maximum cost of 20,000 base units, which equals $0.02 per request (USDC uses 6 decimals).
The provider lowpaymentfee.com hosts a broad catalog of x402-gated APIs spanning data & analytics, AI/ML inference, finance/Web3, and infrastructure utilities — all priced at $0.02 per request. This particular endpoint falls under the finance category and appears to return performance metrics for a portfolio. No API keys or rate limits are advertised; access is granted purely through the x402 payment protocol.
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 portfolio performance response contains or what parameters the POST body accepts. The endpoint is confirmed live (returns a valid 402 challenge), but the lack of documentation makes it difficult to know what data to send or expect back.
Capabilities
Use cases
- —Retrieving performance metrics for a specific investment portfolio
- —Integrating portfolio performance data into dashboards or agent workflows
- —Programmatic access to portfolio returns without API key management
Fit
Best for
- —Agents or apps that need on-demand portfolio performance data with no subscription
- —Developers experimenting with x402 micropayment-gated APIs
- —Crypto-native workflows already operating on Base network
Not for
- —Users who need detailed API documentation or schema before integrating
- —Bulk historical portfolio data retrieval (no evidence of batch support)
- —Non-crypto users unfamiliar with x402 payment flows
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/13/performance \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is confirmed live with 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 showing only 'Connect wallet'. The purpose of the endpoint can only be inferred from the URL path.
Warnings
- —No API documentation available — docs, pricing, and README pages are all empty
- —No request body schema or response schema provided; input/output format is unknown
- —Portfolio ID 13 is hardcoded in the URL; unclear if other portfolio IDs are accessible
- —Provider site appears to be a generic x402 API storefront with many endpoints but no substantive docs for any of them
Citations
- —Endpoint returns 402 with x402 challenge advertising USDC on Base network at maxAmountRequired 20000https://lowpaymentfee.com/api/v1/portfolios/13/performance
- —All APIs priced at $0.02/request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/13/performance