x402-gated portfolio endpoint on Base, pay $0.02 per request in USDC — no API keys required.
What it does
This endpoint at lowpaymentfee.com provides access to a "portfolios" resource (ID 69) behind an x402 paywall. The provider operates a broad catalog of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities, all priced at $0.02 per request settled in USDC on the Base network. No API keys, accounts, or rate limits are advertised — callers simply attach an x402 payment header with each request.
The specific endpoint `/api/v1/portfolios/69` is listed under "Premium API Access" but its exact response payload is undocumented in the crawled material. The x402 challenge confirms it is live, accepts POST requests, and requires up to 20,000 base-unit USDC (i.e., $0.02 given USDC's 6 decimals) per call, paid to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` on Base. The payment scheme is "exact" with a 300-second timeout.
Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all returned only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no response schema, and no example payloads available. The portfolio endpoint itself does not appear in the homepage's listed API catalog, making it unclear what data it returns. Prospective callers should be aware of this documentation gap.
Capabilities
Use cases
- —Fetching portfolio data via a single micropayment without needing an API key
- —Agent-driven programmatic access to portfolio resources using x402 payment protocol
- —Integrating low-cost, on-demand data retrieval into Web3 workflows
Fit
Best for
- —Developers wanting zero-signup, pay-as-you-go API access
- —AI agents that can settle x402 payments in USDC on Base
- —Quick one-off data fetches where subscription pricing is overkill
Not for
- —Users who need detailed API documentation or response schemas before integrating
- —High-volume batch 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/69 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no documentation, no OpenAPI spec, no response schema, and no example payloads. The specific portfolio endpoint doesn't appear in the provider's own homepage catalog, making its purpose unclear. This is effectively a stub listing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README pages all return only a wallet-connect prompt with no content.
- —The /api/v1/portfolios/69 endpoint is not listed in the provider's homepage API catalog; its response format and data content are unknown.
- —No OpenAPI spec or output schema provided; callers cannot know the response structure before paying.
- —Provider site appears to be a generic multi-category API storefront; quality and reliability of individual endpoints is unverifiable.
Citations
- —The endpoint returns a 402 challenge requiring USDC payment on Base with maxAmountRequired of 20000 base unitshttps://lowpaymentfee.com/api/v1/portfolios/69
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/69
- —Provider advertises $0.02 per request, no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —The homepage lists APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com