Pay-per-call portfolio transactions endpoint on Base via x402 (USDC, $0.02/request).
What it does
This x402-enabled endpoint at lowpaymentfee.com provides access to portfolio transaction data via a POST request to `/api/v1/portfolios/29/transactions`. It is part of a broader platform offering data & analytics, AI/ML inference, finance/Web3, and infrastructure utility APIs, all priced at $0.02 per request with no API keys, no rate limits, and no commitments required.
Payment is settled on the Base network using USDC (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`). The x402 challenge specifies a `maxAmountRequired` of 20000 base units, which at 6 decimals equals $0.02 USD per call. The endpoint uses the "exact" payment scheme with a 300-second timeout. No OpenAPI schema or detailed documentation was found beyond the landing page; the docs, pricing, and API pages all returned only a "Connect wallet" prompt with no substantive content.
Because this specific endpoint path (`/portfolios/29/transactions`) suggests it is scoped to a particular portfolio (ID 29), it is unclear whether the caller can parameterize the portfolio ID or whether this is a fixed demo/sample resource. The platform advertises many other endpoints across analytics, AI, finance, and utility categories, all at the same $0.02 price point. Without request/response schema documentation, the exact input format and output structure remain unknown.
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 payment
Fit
Best for
- —Developers wanting API access without signup or API keys
- —Agents that can settle x402 payments in USDC on Base
- —Low-volume or sporadic access to portfolio transaction data
Not for
- —High-volume bulk data export (no documented batch endpoints)
- —Users who need detailed API documentation or response schemas before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/29/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is no OpenAPI schema, no request/response documentation, and all doc pages return only a wallet-connect prompt. The specific endpoint path (/portfolios/29) is ambiguous. Effectively a stub listing.
Warnings
- —No OpenAPI or request/response schema available — input and output formats are unknown.
- —Documentation pages (/docs, /pricing, /api, /README) all return only 'Connect wallet' with no substantive content.
- —The endpoint path includes a hardcoded portfolio ID (29); it is unclear if this is parameterizable or a fixed resource.
- —The platform lists many endpoints on its landing page but none have documented schemas.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units in USDC on Base network.https://lowpaymentfee.com/api/v1/portfolios/29/transactions
- —All APIs on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access.https://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base.https://lowpaymentfee.com/api/v1/portfolios/29/transactions