x402-gated portfolio endpoint on Base, pay-per-request with USDC at $0.02/call.
What it does
This endpoint at lowpaymentfee.com provides premium API access to a specific portfolio resource (`/api/v1/portfolios/54`) via the x402 payment protocol. The endpoint is live and returns a standard 402 challenge requiring payment in USDC on the Base network. The maximum amount required per request is 20,000 base units of USDC (6 decimals), which equals $0.02 USD — consistent with the site-wide pricing of $0.02 per request advertised on the provider's landing page.
The provider, lowpaymentfee.com, hosts a broad catalog of x402-gated APIs spanning data & analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints share the same $0.02/request pricing with no API keys, no rate limits, and no minimum commitments. Payment settles on the Base L2 network using USDC (contract `0x8335...2913`).
The specific `/api/v1/portfolios/54` endpoint is not listed on the provider's main catalog page, and no documentation describes its request or response schema. The crawled docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content. Without schema details, example payloads, or documentation for this particular resource, the exact data returned and the expected POST body remain unknown. The endpoint is confirmed live via the 402 challenge, but consumers should expect to experiment or contact the provider for integration details.
Capabilities
Use cases
- —Fetching portfolio data on-demand with per-request USDC micropayments
- —Integrating pay-as-you-go financial data into agent workflows
- —Accessing premium content without API key registration
Fit
Best for
- —Agents or services that can settle x402 payments in USDC on Base
- —Developers wanting keyless, pay-per-request portfolio data access
- —Low-volume consumers who prefer no subscription commitments
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone unable to transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/54 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge with clear pricing ($0.02 USDC on Base), but there is no documentation, no OpenAPI schema, no request/response examples, and the specific portfolio resource is not even listed on the provider's own catalog. Effectively a stub with verified liveness.
Warnings
- —No documentation available for /api/v1/portfolios/54 — request body and response schema are unknown
- —This specific endpoint is not listed on the provider's main catalog page
- —All doc/pricing/README pages returned only 'Connect wallet' with no content
- —No OpenAPI spec or AI plugin manifest found
Citations
- —The endpoint returns a 402 challenge requiring USDC payment on Base with maxAmountRequired of 20000 base unitshttps://lowpaymentfee.com/api/v1/portfolios/54
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/54
- —Site-wide pricing is $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The provider offers APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com