x402-gated portfolio transactions endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com provides access to portfolio transaction data via a POST request to `/api/v1/portfolios/42/transactions`. It is part of a broader platform (lowpaymentfee.com) that offers dozens of x402-gated API endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities.
The specific endpoint probed here is gated by the x402 protocol (version 1) using the "exact" payment scheme on the Base network. The payment asset is USDC (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) with a maximum amount required of 20,000 base units, which equals $0.02 USD (USDC uses 6 decimals). Payment is sent to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` with a timeout of 300 seconds.
The platform advertises a flat $0.02 per request across all endpoints, with no API keys, no rate limits, no minimums, and instant access. However, documentation pages (docs, pricing, README) all returned only a "Connect wallet" prompt with no substantive content, so the actual request/response schemas for this particular transactions endpoint are unknown. The endpoint is confirmed live (returns 402 with a valid x402 challenge), but without documentation or examples, the exact input parameters and output format cannot be determined.
Capabilities
Use cases
- —Retrieving transaction history for a specific portfolio
- —Programmatic access to portfolio transaction data without API key management
- —Agent-driven portfolio monitoring with per-call USDC payments
Fit
Best for
- —Agents or applications that need on-demand portfolio transaction data
- —Users who prefer pay-per-call pricing without subscriptions
- —Developers building on Base who want USDC-settled API access
Not for
- —Users needing detailed API documentation or schema guarantees before integration
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/42/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is confirmed live with a valid x402 challenge and clear pricing ($0.02 USDC on Base). However, there is no documentation, no request/response schema, and no examples available — all doc pages returned only 'Connect wallet' with no content. The endpoint path suggests portfolio transaction data but specifics are entirely unknown.
Warnings
- —No API documentation available — all doc pages return only a 'Connect wallet' prompt with no content
- —Request body schema and response format are completely unknown
- —The endpoint path references a hardcoded portfolio ID (42); unclear if this is parameterized or fixed
- —Platform appears to list many endpoints but none have documented schemas
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units in USDC on Base networkhttps://lowpaymentfee.com/api/v1/portfolios/42/transactions
- —Platform advertises $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/42/transactions