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 the x402 payment protocol. The specific resource `/api/v1/portfolios/74/transactions` accepts POST requests and is gated behind an x402 challenge requiring payment in USDC on the Base network. The maximum amount required per call is 20,000 base units of USDC (6 decimals), which equals $0.02 per request.
The parent site lowpaymentfee.com hosts a broad collection of x402-gated APIs spanning data & analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are uniformly priced at $0.02 per request with no API keys, no rate limits, and no minimum commitments. Payments settle on the Base L2 network using USDC (contract 0x8335…2913).
The specific endpoint listed here — portfolios/74/transactions — appears to be a portfolio-specific transactions resource, likely returning transaction history or allowing transaction submission for portfolio ID 74. However, no detailed documentation, request schema, or response schema was found in the crawl. The docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content. Without further documentation it is unclear what fields the POST body expects or what the response structure looks like.
Capabilities
Use cases
- —Retrieving or submitting transactions for a specific portfolio via pay-per-call x402
- —Integrating portfolio transaction data into automated trading or analytics pipelines
- —Agent-driven portfolio management where per-request micropayments replace API key subscriptions
Fit
Best for
- —Developers wanting keyless, pay-per-use access to portfolio transaction data
- —AI agents that can settle x402 payments in USDC on Base
- —Projects needing low-friction API access without signup or rate limits
Not for
- —Users who need detailed API documentation or response schemas before integrating
- —High-volume consumers who would prefer subscription-based pricing over per-call fees
- —Anyone unable to pay with USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/portfolios/74/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no request/response documentation, no examples, and the docs pages are empty. The specific purpose of the portfolios/74/transactions endpoint is unclear, making this effectively a stub listing.
Warnings
- —No API documentation available — docs, pricing, and README pages all return only a wallet-connect prompt with no content.
- —No request or response schema provided; the POST body structure is unknown.
- —The endpoint targets a hardcoded portfolio ID (74); it is unclear whether this is a demo or a real portfolio resource.
- —The site lists many diverse API categories (AI, finance, infrastructure) all at $0.02 — the actual functionality behind each endpoint is unverified.
Citations
- —The endpoint returns a 402 challenge requiring USDC payment on Base network with maxAmountRequired of 20000 base unitshttps://lowpaymentfee.com/api/v1/portfolios/74/transactions
- —USDC contract address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/portfolios/74/transactions
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The site hosts APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com