x402-gated portfolio data endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a specific portfolio resource (portfolio ID 21) via the x402 payment protocol. The endpoint is live and returns a 402 challenge requiring payment in USDC on the Base network. Each request costs $0.02 (20,000 base units of USDC with 6 decimals). Payment is settled on-chain to the specified wallet address, with no API keys, rate limits, or subscriptions required.
The provider lowpaymentfee.com hosts a broader suite of x402-gated APIs spanning data & analytics (metrics, reports, data export, insights), AI & machine learning (sentiment analysis, text summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at $0.02 per request.
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no description of what the portfolio endpoint actually returns. The endpoint accepts POST requests and returns application/json, but the exact payload structure is unknown.
Capabilities
Use cases
- —Fetching portfolio data on-demand with per-request USDC micropayments
- —Agent-driven access to financial portfolio information without API key management
- —Integrating pay-per-call portfolio lookups into automated trading or analytics pipelines
Fit
Best for
- —Developers wanting keyless, pay-per-use API access settled in USDC on Base
- —AI agents that can handle x402 payment challenges natively
- —Users who prefer on-chain micropayments over subscription billing
Not for
- —Users who need detailed API documentation or request/response schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/21 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is zero documentation on what the portfolio endpoint accepts or returns. No OpenAPI schema, no examples, and all doc pages are empty beyond a wallet connect prompt. The listing is effectively a stub.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or request/response schema provided; the actual data returned by /api/v1/portfolios/21 is completely unknown.
- —The specific purpose of 'portfolio 21' is undocumented; it is unclear what data this resource represents.
- —Cannot verify the quality or accuracy of returned data without any example responses.
Citations
- —Endpoint returns HTTP 402 with x402 challenge requiring USDC payment on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/21
- —maxAmountRequired is 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913), equating to $0.02https://lowpaymentfee.com/api/v1/portfolios/21
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —Provider offers APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com