x402-gated portfolio endpoint on Base, pay $0.02 per request in USDC — no API keys required.
What it does
This endpoint at `/api/v1/portfolios/61` 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, and infrastructure utilities. The specific `/portfolios/61` resource is listed under "Premium API Access" and returns JSON data via POST. Payment is settled on the Base network using USDC (contract `0x8335…2913`) at a cost of $0.02 per call (20,000 base units with 6 decimals).
The platform advertises a simple pricing model: $0.02 per request across all endpoints, with no API keys, no rate limits, no minimums, and instant access. The x402 challenge was successfully captured, confirming the endpoint is live and accepting the `exact` payment scheme with a 300-second timeout. However, the specific data returned by `/api/v1/portfolios/61` is not documented — the title "Premium API Access" is generic and the crawl yielded no schema or example responses for this particular route.
Documentation pages (`/docs`, `/api`, `/pricing`, `/README`) all returned only a "Connect wallet" prompt with no substantive content, so the actual payload structure, fields, and use case of the portfolios endpoint remain unknown. The platform hosts many other endpoints (sentiment analysis, summarization, price feeds, geocoding, etc.) all at the same price point, but without documentation it is unclear what portfolio data this specific endpoint provides.
Capabilities
Use cases
- —Fetching portfolio data (specific contents unknown) via a single paid POST request
- —Integrating pay-per-request data access into agent workflows without managing API keys
- —Demonstrating x402 payment protocol integration on Base
Fit
Best for
- —Developers experimenting with x402 pay-per-request protocols
- —Agents that need keyless, on-demand API access settled in USDC on Base
- —Low-volume consumers who prefer per-call pricing over subscriptions
Not for
- —Users who need well-documented API schemas and response examples 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/61 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and the x402 challenge is well-formed with clear pricing ($0.02 USDC on Base). However, there is no documentation, no response schema, no example payloads, and the purpose of '/portfolios/61' is entirely opaque. All doc pages returned only 'Connect wallet' with no content.
Warnings
- —No documentation available — all doc pages (/docs, /api, /pricing, /README) return only a 'Connect wallet' prompt
- —The specific data returned by /api/v1/portfolios/61 is completely undocumented; 'Premium API Access' is a generic label
- —No OpenAPI spec, no response schema, and no example responses are available
- —The platform lists many diverse endpoints (AI, finance, utils) all at $0.02 — unclear if all are fully functional
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units in USDC on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/61
- —Platform pricing is $0.02 per request with no API keys, no rate limits, no minimumshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/61
- —Documentation pages return only 'Connect wallet' with no substantive contenthttps://lowpaymentfee.com/docs