x402-gated portfolio transactions endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com exposes a POST-based transactions API for a specific portfolio (ID 79) behind an x402 paywall. The x402 challenge confirms it is live and accepts exact-scheme payments on the Base network in USDC (contract 0x8335…2913). The maximum amount required per call is 20,000 base units of USDC, which with 6 decimals equals $0.02 per request.
The hosting site lowpaymentfee.com advertises a broad catalog of pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $0.02 per call with no API keys, no rate limits, and no commitments. However, the specific endpoint being listed here (/api/v1/portfolios/79/transactions) is not explicitly documented on the site's landing page or in any crawled documentation. Its description in the x402 challenge is simply "Premium API Access," and no request/response schema is provided beyond the fact that it accepts HTTP POST and returns application/json.
Because there is no OpenAPI spec, no detailed docs, and no example payloads available for this particular endpoint, the exact functionality — what fields to send, what transaction data is returned — remains unclear. The endpoint is confirmed live (402 challenge captured), and the pricing and payment mechanics are well-defined, but consumers will need to experiment or contact the provider to understand the request format.
Capabilities
Use cases
- —Fetching or submitting portfolio transaction records via a pay-per-call model
- —Integrating low-cost financial transaction data into agent workflows
- —Programmatic access to portfolio data without API key management
Fit
Best for
- —Agents or bots that need on-demand portfolio transaction data with no signup
- —Developers experimenting with x402 payment-gated APIs on Base
- —Micropayment-based access to financial endpoints
Not for
- —Users who need well-documented request/response schemas before integrating
- —High-volume batch processing where per-request fees add up
- —Anyone needing non-USDC or non-Base-network payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/79/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live via a valid x402 402 challenge, and pricing/payment details are clear. However, there is no OpenAPI spec, no request/response schema, no documentation for this specific endpoint, and the crawled pages beyond the landing page returned only 'Connect wallet' with no useful content. The endpoint's actual functionality is opaque.
Warnings
- —No documentation or schema available for /api/v1/portfolios/79/transactions — the endpoint is not listed on the provider's landing page
- —Crawled docs, API, pricing, and README pages all returned only 'Connect wallet' with no substantive content
- —Request and response formats are unknown; consumers must experiment or contact the provider
Citations
- —The x402 challenge confirms the endpoint is live, accepts USDC on Base network, with maxAmountRequired of 20000 base units ($0.02).https://lowpaymentfee.com/api/v1/portfolios/79/transactions
- —The site advertises all APIs at $0.02/request with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base.https://lowpaymentfee.com/api/v1/portfolios/79/transactions