x402-gated portfolio endpoint on Base, pay-per-call with USDC at $0.02/request.
What it does
This endpoint at `/api/v1/portfolios/82` is part of the lowpaymentfee.com platform, which offers a collection of x402-protocol pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities. The specific `/portfolios/82` resource is listed under "Premium API Access" but its exact data payload is not documented beyond the generic description. All endpoints on the platform share the same pricing model: $0.02 per request, settled in USDC on the Base network via the x402 protocol.
The platform advertises no API keys, no rate limits, and instant access — callers simply attach an x402 payment header with each request. The probe confirms the endpoint is live, returning a proper 402 challenge with `maxAmountRequired` of 20000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment timeout is 300 seconds. The endpoint accepts POST requests.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no description of request parameters, and no example of the response body for this specific portfolio endpoint. The broader site lists many endpoint categories but provides no detailed documentation for any of them. Without knowing what data `/portfolios/82` actually returns, callers should treat this as an exploratory integration.
Capabilities
Use cases
- —Fetching portfolio data via a single paid API call without needing API keys
- —Integrating pay-per-request data access into autonomous agent workflows
- —Testing x402 protocol payment flows against a live endpoint
Fit
Best for
- —Developers experimenting with x402 pay-per-request protocols
- —Agents needing keyless, on-demand API access settled in USDC on Base
- —Low-volume callers who want no subscription commitments
Not for
- —Users who need detailed API documentation or response schema guarantees before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/82 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is zero documentation on what the endpoint actually returns, no request/response schema, and no examples. The docs pages are empty beyond a wallet connect prompt. This is effectively a stub listing.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content
- —No OpenAPI or response schema provided; the actual data returned by /api/v1/portfolios/82 is unknown
- —The specific meaning of 'portfolios/82' is undocumented — unclear what data this resource represents
- —Multiple other endpoints listed on the site share identical pricing and descriptions, suggesting the platform may be a demo or template
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/82
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/82
- —Docs, API, pricing, and README pages render only 'Connect wallet' with no substantive contenthttps://lowpaymentfee.com/docs