x402-gated portfolio endpoint on Base, pay $0.02 per request in USDC — no API keys needed.
What it does
This endpoint at lowpaymentfee.com provides premium API access to a specific portfolio resource (portfolio ID 27) via the x402 payment protocol. It is part of a broader platform that offers dozens of pay-per-call endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all gated behind x402 micro-payments on the Base network.
The endpoint accepts POST requests and returns JSON. Payment is settled in USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base) using the "exact" x402 scheme. The maximum amount required per call is 20,000 base units of USDC, which equals $0.02 (USDC uses 6 decimals). 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 platform advertises a uniform $0.02/request pricing across all its endpoints. Documentation pages exist at /docs, /pricing, and /api but currently render only a "Connect wallet" prompt, so detailed request/response schemas for this specific portfolio endpoint are unavailable. The endpoint is confirmed live (returns a well-formed 402 challenge), but without documentation or example responses, the exact data returned by the portfolio resource is unknown.
Capabilities
Use cases
- —Fetching portfolio data without managing API keys or subscriptions
- —Agent-driven portfolio queries settled instantly in USDC on Base
- —Integrating low-cost, pay-per-call portfolio lookups into trading bots or dashboards
Fit
Best for
- —Developers who want keyless, pay-per-request portfolio data
- —AI agents with x402-compatible wallets on Base
- —Prototyping or low-volume use cases where $0.02/call is cost-effective
Not for
- —High-volume production workloads needing bulk pricing or SLAs
- —Users who need detailed API documentation or guaranteed response schemas before integrating
- —Callers without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/27 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_proof>"Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no documentation beyond a wallet-connect prompt, no example request/response payloads, and the purpose of 'portfolios/27' is entirely opaque. This is effectively a stub listing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet'
- —The exact data returned by /api/v1/portfolios/27 is unknown; 'Premium API Access' is the only description
- —No request body schema or response schema is provided
- —Portfolio ID 27 is hardcoded in the URL with no explanation of what it represents
Citations
- —Uniform pricing of $0.02 per request across all endpoints, no API keys, no rate limitshttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired 20000 in USDC (6 decimals) on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/27
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/27
- —Documentation pages (/docs, /pricing, /api, /README) render only 'Connect wallet'https://lowpaymentfee.com/docs