x402-gated portfolio endpoint on Base, pay-per-request with USDC.
What it does
This endpoint at lowpaymentfee.com provides a "Premium API Access" resource at `/api/v1/portfolios/62` via the x402 payment protocol. It is live and returns a 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 per call. Payment is settled on-chain to the specified wallet address using the "exact" payment scheme.
The provider site lowpaymentfee.com hosts a broader catalog of pay-per-request APIs spanning data & analytics, AI/ML (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation) — all priced at $0.02 per request with no API keys, no rate limits, and no commitments. However, this specific listing is for the `/api/v1/portfolios/62` endpoint, which is not described on the landing page catalog. Its exact response payload and purpose are unclear — the name "portfolios" suggests financial portfolio data, but no documentation, schema, or example responses are available.
The endpoint accepts HTTP POST requests and returns `application/json`. No OpenAPI spec, detailed docs, or example payloads were found during crawling; the docs, pricing, and API pages all rendered only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Retrieving portfolio data (likely financial) on a per-request payment basis
- —Agent-driven data fetching with on-chain USDC micropayments on Base
- —Integrating pay-as-you-go API access without API keys or subscriptions
Fit
Best for
- —Agents or services that need keyless, pay-per-call API access
- —Users who prefer on-chain USDC micropayments over traditional billing
- —Developers exploring x402 protocol integrations on Base
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Anyone who cannot transact in USDC on the Base network
Quick start
# The endpoint requires an X-PAYMENT header with a valid x402 payment proof.
# Without a payment library, you'll get a 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/62
# Returns 402 with x402 challenge. Use an x402-compatible client to attach payment.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no documentation, no OpenAPI schema, no example request/response, and the specific purpose of /api/v1/portfolios/62 is not described anywhere on the site. The docs and other pages rendered only wallet-connect prompts with no content.
Warnings
- —No documentation available — docs, pricing, and API pages all show only 'Connect wallet' with no further content.
- —The /api/v1/portfolios/62 endpoint is not listed in the provider's own catalog of available APIs on the landing page.
- —No OpenAPI spec, request schema, or response schema found; the exact data returned is unknown.
- —Purpose of 'portfolios/62' is inferred from the URL path only — could be a demo or placeholder endpoint.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/62
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/62
- —The provider advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The site catalogs APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com