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 37) 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 tracked portfolio. No API keys or rate limits are advertised; access is granted purely via the x402 payment header.
Documentation 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 example payloads available. The endpoint is confirmed live (returns a proper 402 challenge), but the actual shape of the response data and any required POST body fields are unknown.
Capabilities
Use cases
- —Retrieving performance metrics for a tracked investment portfolio
- —Integrating portfolio performance data into dashboards or agents
- —Automated portfolio monitoring with per-request micropayments
Fit
Best for
- —Agents or apps needing on-demand portfolio performance data without subscription commitments
- —Developers experimenting with x402 micropayment-gated finance APIs
- —Low-volume consumers who prefer pay-per-call pricing
Not for
- —Users needing detailed API documentation or request/response schemas before integrating
- —High-frequency trading systems requiring sub-second latency guarantees
- —Users without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/37/performance \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing. However, there is no documentation, no OpenAPI spec, no request/response schema, and no examples. The docs pages are empty stubs. The purpose of the endpoint can only be inferred from the URL path.
Warnings
- —No API documentation available — docs, pricing, API, and README pages all show only 'Connect wallet' with no content
- —No request body schema documented; unknown what POST body fields are expected
- —No response schema documented; the shape of the performance data is unknown
- —Portfolio ID 37 is hardcoded in the URL; unclear if other portfolio IDs are accessible or how portfolios are created
- —Provider appears to be a generic x402 demo site with many endpoints; quality and reliability of underlying data is unverified
Citations
- —Endpoint returns 402 with x402 challenge requiring USDC payment on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/37/performance
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/37/performance
- —Maximum amount required is 20000 base units ($0.02 USDC)https://lowpaymentfee.com/api/v1/portfolios/37/performance
- —All APIs on the site are priced at $0.02 per request with no API keys, no rate limitshttps://lowpaymentfee.com