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/91/transactions`. It is part of a broader platform (lowpaymentfee.com) that offers a variety of pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all gated behind the x402 payment protocol.
The specific endpoint probed here charges up to $0.02 per request (maxAmountRequired of 20,000 base units of USDC on Base, where USDC has 6 decimals = $0.02). Payment is settled on the Base network using USDC (contract 0x8335…2913) via the x402 "exact" scheme. No API keys or rate limits are advertised; access is granted per-call upon valid payment. The endpoint accepts POST requests and returns application/json.
Documentation is extremely sparse. The crawled docs, pricing, and API pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema, and no usage examples available from the site. The endpoint is confirmed live (402 challenge returned), but the actual functionality behind the paywall — what fields the transaction data contains, what parameters the POST body expects — cannot be determined from the available material.
Capabilities
Use cases
- —Retrieving transaction history for a specific portfolio
- —Programmatic access to portfolio transaction data without API key management
- —Agent-driven financial data retrieval with per-call USDC micropayments
Fit
Best for
- —Developers wanting keyless, pay-per-use portfolio transaction data
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing detailed API documentation or request/response schemas before purchasing
- —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/91/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The actual data returned behind the paywall is unknown, making this effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, and API pages all render only 'Connect wallet'
- —No OpenAPI or request/response schema provided; request body format and response structure are unknown
- —The endpoint path references a specific portfolio ID (91); it is unclear whether other portfolio IDs are supported or what this portfolio represents
- —The platform lists many API categories (AI, analytics, finance, etc.) but none have documented schemas
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/portfolios/91/transactions
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/portfolios/91/transactions
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Docs, pricing, API, and README pages render only a 'Connect wallet' prompt with no additional contenthttps://lowpaymentfee.com/docs