x402-gated account balance endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com exposes an account balance resource (`/api/v1/accounts/73/balance`) behind an x402 paywall. It accepts POST requests and returns JSON. Payment is settled on the Base network using USDC (contract 0x8335…2913) via the x402 "exact" scheme. The maximum amount required per call is 20,000 base units of USDC, which equals $0.02 (USDC uses 6 decimals).
The broader lowpaymentfee.com platform advertises a catalog of pay-per-request APIs spanning data & analytics, AI/ML (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 listed at $0.02 per request with no API keys, no rate limits, and no commitments required.
However, this specific endpoint (`/accounts/73/balance`) is not explicitly listed on the site's catalog page, and there is no documentation describing its request body schema or response format. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. The endpoint is confirmed live via a valid 402 challenge, but the actual functionality behind the paywall is opaque.
Capabilities
Use cases
- —Querying account balance data behind a micropayment wall
- —Programmatic pay-per-request access without API key management
- —Agent-driven balance lookups settled in USDC on Base
Fit
Best for
- —Developers wanting keyless, pay-per-call API access
- —AI agents with x402-compatible wallets on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation before purchasing
- —Anyone requiring free or trial access to evaluate the endpoint
- —Use cases needing high-throughput batch queries (no documented rate limits but no guarantees either)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/accounts/73/balance \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is zero documentation on request/response schemas, no OpenAPI spec, and the specific /accounts/73/balance path is not listed in the site's own catalog. Docs pages are empty beyond a wallet-connect prompt. Functionality behind the paywall cannot be verified.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet'
- —The specific endpoint /api/v1/accounts/73/balance is not listed in the site's own API catalog
- —No request body schema or response schema documented anywhere
- —Cannot verify what data is actually returned after payment
- —The endpoint path includes a hardcoded account ID (73), suggesting it may be a demo or single-purpose resource
Citations
- —The x402 challenge requires 20,000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/accounts/73/balance
- —All listed APIs are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform catalogs endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC contract address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/accounts/73/balance