x402-gated premium API access on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The specific resource `/api/v1/portfolios/49` sits within a broader platform that offers dozens of pay-per-call API endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services — all gated behind x402 challenges on the Base network.
The endpoint accepts POST requests and returns JSON. Payment is settled in USDC (contract 0x8335…2913 on Base) using the x402 "exact" scheme. The max amount required is 20,000 base units, which at 6 decimals equals $0.02 per request. No API keys or rate limits are advertised; callers simply attach an X-PAYMENT header with a valid x402 payment proof. The payment timeout is 300 seconds.
The specific functionality behind `/api/v1/portfolios/49` is not documented beyond the label "Premium API Access." The site's landing page groups its APIs into categories (Data & Analytics, AI & ML, Finance & Web3, Infrastructure), but this particular portfolios endpoint is not listed among them. Without further documentation or example responses, the exact data returned is unknown. The docs, pricing, and API pages all render only a "Connect wallet" prompt with no additional technical detail.
Capabilities
Use cases
- —Fetching portfolio data (portfolio ID 49) via a single micropayment
- —Integrating pay-per-request data access into autonomous agents
- —Accessing premium API content without API keys or subscriptions
Fit
Best for
- —Agents or scripts that need keyless, pay-as-you-go API access
- —Developers experimenting with x402 payment-gated endpoints
- —Use cases requiring USDC micropayments on Base L2
Not for
- —Users who need detailed API documentation or response schemas before integrating
- —High-volume consumers who prefer subscription-based pricing over per-call payments
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/49 \
-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 what the /portfolios/49 endpoint actually returns, no request/response schema, and the docs pages are empty. The specific resource is not even listed on the provider's own landing page, making it effectively a stub.
Warnings
- —No documentation exists for the /api/v1/portfolios/49 endpoint — its purpose and response format are unknown
- —All doc/pricing/API pages render only 'Connect wallet' with no technical content
- —This specific endpoint is not listed among the provider's advertised APIs, raising questions about its status
- —No OpenAPI spec, no example responses, no request schema available
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/49
- —The platform advertises $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/49
- —Docs, pricing, and API pages show only 'Connect wallet' with no additional contenthttps://lowpaymentfee.com/docs