Pay-per-call portfolio data endpoint on Base via x402, settled in USDC at $0.02/request.
What it does
This x402-enabled endpoint at `/api/v1/portfolios/67` is part of the lowpaymentfee.com platform, which offers a collection of pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. Each call is settled on the Base network using USDC (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) with no API keys, no rate limits, and no subscriptions required.
The specific endpoint probed (`/portfolios/67`) is listed under "Premium API Access" and returns `application/json`. The x402 challenge advertises a `maxAmountRequired` of 20,000 base units of USDC (6 decimals), which equals $0.02 per request — consistent with the site-wide flat pricing of $0.02/request. Payment is made via the x402 `exact` scheme with a 300-second timeout.
Documentation on the site is extremely thin — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema, and no example payloads available. The endpoint name "portfolios/67" suggests it returns portfolio-related data (possibly financial), but the exact input parameters and response structure are unknown. The platform hosts many other endpoints across categories like sentiment analysis, text summarization, geocoding, and crypto gas estimates, all at the same $0.02 price point.
Capabilities
Use cases
- —Fetching portfolio data on-demand without subscription or API key management
- —Integrating pay-per-call financial data into agent workflows
- —Testing x402 payment protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents needing keyless, pay-per-request data access on Base
- —Low-volume or sporadic API consumers who want no commitments
Not for
- —High-volume consumers needing bulk pricing or rate guarantees
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/67 \
-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, but there is no OpenAPI spec, no documentation beyond a wallet-connect prompt, no request/response schema, and no examples. The purpose of '/portfolios/67' is unclear beyond the generic 'Premium API Access' label.
Warnings
- —No OpenAPI specification or request/response schema available
- —Documentation pages (docs, API, pricing, README) all render only 'Connect wallet' with no usable content
- —The exact data returned by /api/v1/portfolios/67 is unknown — 'Premium API Access' is a generic label
- —The platform appears to be a demo or early-stage project; endpoint reliability is unverified
Citations
- —The x402 challenge advertises maxAmountRequired of 20000 base units of USDC on Base network with exact schemehttps://lowpaymentfee.com/api/v1/portfolios/67
- —Site-wide pricing is $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/67
- —Documentation, API, pricing, and README pages render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs