x402-gated portfolio transactions endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to portfolio transaction data via a POST request to `/api/v1/portfolios/33/transactions`. It is part of a broader platform offering data & analytics, AI/ML inference, finance/Web3, and infrastructure utility APIs, all gated behind the x402 payment protocol on the Base network.
The endpoint accepts USDC payments on Base (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) with a maximum amount of 20,000 base units, which equals $0.02 (USDC uses 6 decimals). The payment scheme is "exact" and settles to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3`. No API keys are required; access is granted per-request via the X-PAYMENT header. The platform advertises no rate limits and instant access.
Documentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no description of what fields the transactions endpoint accepts or returns. The specific portfolio (ID 33) is hardcoded in the URL, and it is unclear whether this represents a fixed demo portfolio or a specific dataset. The endpoint is confirmed live via a valid 402 challenge response.
Capabilities
Use cases
- —Fetching transaction history for a specific portfolio
- —Integrating portfolio transaction data into dashboards or analytics pipelines
- —Agent-driven portfolio monitoring with per-call micropayments
Fit
Best for
- —Developers wanting keyless, pay-per-request access to portfolio transaction data
- —AI agents that can settle USDC micropayments on Base
- —Prototyping x402-based payment flows with low per-call costs
Not for
- —Users needing detailed API documentation or request/response schemas before integrating
- —High-volume batch retrieval where per-request pricing may add up
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/33/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, confirming pricing and payment details. However, there is no OpenAPI schema, no request/response documentation, no examples, and the docs pages are empty. The purpose and data model of the specific '/portfolios/33/transactions' endpoint are unclear.
Warnings
- —No API documentation available — /docs, /api, /pricing, and /README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or JSON schema describing request body or response format.
- —The portfolio ID '33' is hardcoded in the endpoint URL; unclear what data it represents.
- —No request or response examples available from any source.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units in USDC on Base.https://lowpaymentfee.com/api/v1/portfolios/33/transactions
- —The platform advertises $0.02 per request, no API keys, no rate limits, and instant access.https://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.https://lowpaymentfee.com/api/v1/portfolios/33/transactions