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 an x402 payment-gated POST request. The specific resource `/api/v1/portfolios/89/transactions` is part of a broader platform that offers dozens of pay-per-request APIs spanning data analytics, AI/ML inference, finance, crypto, and utility services — all settled on the Base network using USDC.
The x402 challenge confirms the endpoint is live and accepts exact-scheme payments in USDC (contract 0x8335…2913 on Base) with a maximum amount of 20,000 base units, which equals $0.02 per request (USDC uses 6 decimals). No API keys or rate limits are advertised; callers simply attach an X-PAYMENT header with a valid x402 payment proof. The endpoint accepts POST and returns application/json.
The specific data returned by this particular portfolio transactions endpoint is not documented in the crawled material. The site's docs, pricing, and API pages all rendered only a "Connect wallet" prompt with no further content, so the request/response schemas are unknown. The endpoint appears to be one of many on the platform, all priced uniformly at $0.02 per call.
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 USDC payments
Fit
Best for
- —Developers who want keyless, pay-per-request access to portfolio data
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or request/response schemas before integrating
- —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/89/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge with clear pricing ($0.02 USDC on Base). However, there is no documentation of request parameters, response schema, or what 'portfolios/89/transactions' actually returns. The docs pages are empty beyond a wallet-connect prompt, making integration difficult without trial and error.
Warnings
- —No request or response schema is documented; the input/output format is unknown.
- —The docs, pricing, and API pages on the site render only a 'Connect wallet' prompt with no usable documentation.
- —The specific meaning of portfolio ID 89 is unexplained — it may be a demo or placeholder resource.
- —This endpoint's purpose ('Premium API Access') is generic and does not describe the actual data returned.
Citations
- —The endpoint returns a 402 challenge with x402Version 1, accepting USDC on Base with maxAmountRequired of 20000 base units ($0.02).https://lowpaymentfee.com/api/v1/portfolios/89/transactions
- —The platform advertises $0.02 per request with no API keys, no rate limits, and instant access on the Base network.https://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.https://lowpaymentfee.com/api/v1/portfolios/89/transactions