x402-gated portfolio data endpoint on Base, pay-per-request with USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a specific portfolio resource (portfolio ID 32) via the x402 payment protocol. The endpoint is live and returns a 402 challenge requiring payment in USDC on the Base network. The cost per request is $0.02 (20,000 base units of USDC with 6 decimals). Payment is made via the x402 "exact" scheme with no API keys, rate limits, or subscriptions required — callers simply attach an X-PAYMENT header with a valid payment proof.
The broader lowpaymentfee.com platform advertises a range of pay-per-call APIs spanning data analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance and crypto market data, and infrastructure utilities. All endpoints are listed at $0.02 per request and settle on the Base network using USDC. However, the specific endpoint being listed here (/api/v1/portfolios/32) is not explicitly described on the site's landing page, so its exact response schema and data contents are unclear. It appears to be a portfolio-related data resource, but no documentation, example responses, or OpenAPI schema are available.
The site's docs, pricing, and API pages all render only a "Connect wallet" prompt with no substantive documentation, making it impossible to verify the response format or data quality. Callers should be aware that this is a minimally documented endpoint with no published output schema beyond the x402 challenge metadata indicating it returns application/json.
Capabilities
Use cases
- —Fetching portfolio data on-demand with per-request USDC micropayments
- —Integrating pay-as-you-go data access into autonomous agents
- —Accessing financial portfolio information without API key management
Fit
Best for
- —Agents or services that can settle x402 payments on Base
- —Use cases requiring keyless, per-request API access
- —Developers experimenting with x402 payment protocol integrations
Not for
- —Users needing well-documented APIs with published schemas and examples
- —High-volume consumers who need bulk pricing or subscription plans
- —Anyone unable to transact in USDC on the Base network
Quick start
# 1. Send a POST to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/32
# Response: 402 with x402 challenge JSON
# 2. Construct an X-PAYMENT header with a valid USDC payment proof on Base
# 3. Resend the POST with the header:
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/32 \
-H "X-PAYMENT: <payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation, no OpenAPI schema, no example responses, and the specific /portfolios/32 resource is not described anywhere on the site. The docs/pricing/API pages are all empty beyond a wallet connect prompt. This is effectively a stub listing.
Warnings
- —No documentation available — docs, pricing, and API pages all show only 'Connect wallet'
- —The /api/v1/portfolios/32 endpoint is not listed among the site's advertised APIs
- —No output schema or example response is available; response format is unknown
- —No OpenAPI or machine-readable API specification found
Citations
- —The endpoint returns a 402 challenge requiring USDC payment on Base network with maxAmountRequired of 20000 base unitshttps://lowpaymentfee.com/api/v1/portfolios/32
- —The site advertises all endpoints at $0.02 per request with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/32
- —Docs, pricing, and API pages render only a 'Connect wallet' prompt with no substantive contenthttps://lowpaymentfee.com/docs