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 access to a portfolio resource (ID 23) via the x402 payment protocol. It is part of a broader platform that offers dozens of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all gated behind x402 micropayments on the Base network using USDC.
The specific endpoint `/api/v1/portfolios/23` is listed under "Premium API Access" and accepts POST requests. Payment is settled on-chain on Base via USDC (contract 0x8335…2913) to the payee address 0x1A2B…85F3. The x402 challenge advertises a maxAmountRequired of 20,000 base units, which at 6 decimals for USDC equals $0.02 per request — consistent with the platform's uniform $0.02/request pricing across all endpoints.
The platform emphasizes simplicity: no API keys, no rate limits, no minimum commitments, and instant access. However, documentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no description of what the portfolios endpoint actually returns. The endpoint is live (402 challenge confirmed), but without documentation it is unclear what data or functionality the portfolio resource provides.
Capabilities
Use cases
- —Accessing portfolio data with per-request USDC micropayments on Base
- —Agent-driven data retrieval without pre-registration or API keys
- —Programmatic access to premium content gated by on-chain payment
Fit
Best for
- —Developers wanting keyless, pay-as-you-go API access
- —AI agents with x402-compatible payment capabilities
- —Users who prefer on-chain USDC settlement on Base L2
Not for
- —Users needing detailed API documentation or response schemas before integrating
- —High-volume consumers who need bulk/subscription pricing
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/23 \
-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 zero documentation on what the portfolios/23 resource actually returns. No OpenAPI spec, no request/response schemas, and all doc pages render only 'Connect wallet'. The endpoint's purpose must be entirely guessed from its URL path.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README pages all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format for /api/v1/portfolios/23
- —The specific purpose and data returned by the portfolios endpoint is unknown
- —No agents.txt or robots.txt present
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units in USDC on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/23
- —Platform-wide pricing is $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/23
- —Documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet'https://lowpaymentfee.com/docs