x402-gated portfolio endpoint on Base, pay $0.02 per request in USDC — no API keys required.
What it does
This endpoint at lowpaymentfee.com provides access to a specific portfolio resource (`/api/v1/portfolios/97`) via the x402 payment protocol. It is part of a broader platform that offers dozens of pay-per-call API endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all gated behind x402 challenges on the Base network using USDC.
The endpoint accepts POST requests and returns JSON. Payment is settled on-chain via USDC on Base (contract `0x8335...2913`) using the x402 "exact" scheme. The maximum amount required per call is 20,000 base units of USDC (6 decimals), which equals $0.02 USD. There are no API keys, no rate limits, and no subscription commitments — callers simply attach an `X-PAYMENT` header with a valid x402 payment proof.
The specific data returned by `/api/v1/portfolios/97` is not documented in the crawled material. The endpoint is listed under "Premium API Access" but no schema, field descriptions, or example responses are provided. The broader site's documentation, pricing, and API pages all render only a "Connect wallet" prompt with no additional technical detail. Callers should expect a JSON response but will need to discover the exact shape experimentally.
Capabilities
Use cases
- —Fetching portfolio data on-demand with per-request USDC micropayments
- —Integrating pay-per-call data access into autonomous agents without managing API keys
- —Accessing financial or portfolio information via x402 protocol on Base
Fit
Best for
- —Agents or apps that can settle x402 payments on Base
- —Developers wanting keyless, pay-as-you-go API access
- —Low-volume or sporadic callers who prefer per-request billing over subscriptions
Not for
- —Users who need detailed API documentation or response schemas before integrating
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Callers without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/97 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no documentation of request parameters, response schema, or what 'portfolios/97' actually returns. Docs pages render only a wallet-connect prompt with no technical content.
Warnings
- —No documentation available — all doc/pricing/API pages render only 'Connect wallet' with no technical detail
- —The specific resource '/api/v1/portfolios/97' is not listed on the site's homepage catalog; its purpose is unknown
- —No request body schema or response schema is documented; callers must discover the interface experimentally
- —The portfolio ID '97' is hardcoded in the endpoint path — unclear if other IDs exist or what they represent
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/97
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/97
- —Platform advertises $0.02/request, no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —Documentation, pricing, API, and README pages all render only 'Connect wallet' with no additional contenthttps://lowpaymentfee.com/docs