x402-gated account balance endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com provides an account balance lookup via the x402 payment protocol. The specific resource `/api/v1/accounts/120/balance` 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. Payment is made via the "exact" scheme to a specified wallet address, with a timeout of 300 seconds.
The broader lowpaymentfee.com platform advertises a suite of x402-gated APIs spanning data & analytics (metrics, reports, data export, insights), AI & machine learning (sentiment analysis, text 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 minimum commitments.
However, the specific endpoint being listed here — `/api/v1/accounts/120/balance` — is not among the APIs advertised on the landing page. Its purpose appears to be retrieving the balance for account ID 120, but no documentation, request schema, or response schema is available. The docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content. The endpoint is confirmed live (returns a valid 402 challenge), but its actual functionality and response format remain undocumented.
Capabilities
Use cases
- —Querying account balance for account 120 via a single paid API call
- —Integrating x402 pay-per-call balance lookups into agent workflows
- —Demonstrating x402 protocol usage on Base with USDC
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents needing pay-per-call account balance data without API keys
- —Low-friction access to balance information without subscriptions
Not for
- —Production use requiring documented response schemas and SLAs
- —Bulk or high-volume balance queries where per-call pricing is inefficient
- —Users who need detailed API documentation before integration
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/accounts/120/balance \
-H "X-PAYMENT: <x402_payment_token>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but the specific resource (/api/v1/accounts/120/balance) is not documented anywhere on the site. No request or response schema is available, docs pages are empty, and the endpoint's purpose can only be guessed from its URL path. This is effectively a stub listing.
Warnings
- —The endpoint /api/v1/accounts/120/balance is not listed among the advertised APIs on the landing page — its purpose and availability are unclear.
- —No documentation, request schema, or response schema is available for this endpoint.
- —All docs/pricing/API/README pages returned only a 'Connect wallet' prompt with no content.
- —The hardcoded account ID '120' in the URL suggests this may be a specific account resource rather than a general-purpose API.
Citations
- —The x402 challenge requires maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/accounts/120/balance
- —All listed APIs are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform advertises APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/accounts/120/balance