Check account balance via x402 micropayment on Base network for $0.02 per request.
What it does
This endpoint at lowpaymentfee.com returns account balance information for a specific account (ID 139) behind an x402 paywall. It is part of a broader platform offering dozens of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $0.02 per request and settled in USDC on the Base network.
The specific endpoint `/api/v1/accounts/139/balance` accepts POST requests and requires an X-PAYMENT header conforming to x402 version 1 with the "exact" payment scheme. The maximum amount required is 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The response MIME type is application/json.
The platform advertises no API keys, no rate limits, and instant access. Documentation pages (/docs, /pricing, /api, /README) all appear to require a wallet connection and contain no further readable content. Because of this, the actual response schema, request body format, and detailed behavior of this endpoint are unknown beyond what the x402 challenge reveals. The endpoint is confirmed live (returns 402 with a valid x402 challenge).
Capabilities
Use cases
- —Querying account balance data programmatically with per-request USDC micropayments
- —Integrating balance lookups into agent workflows without API key management
- —Demonstrating x402 protocol payment flows on Base network
Fit
Best for
- —Developers experimenting with x402 micropayment protocols
- —Agents needing keyless, pay-per-call account balance queries
- —Projects already using USDC on Base that want frictionless API access
Not for
- —Users needing detailed API documentation or response schema guarantees before integrating
- —High-volume balance queries where $0.02/request adds up significantly
- —Users without USDC on Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/accounts/139/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 documentation pages are all behind a wallet-connect gate and provide no readable content. There is no OpenAPI schema, no example request/response, and the purpose of this specific account balance endpoint (account 139) is unclear. The listing is essentially a stub with pricing and liveness confirmed.
Warnings
- —All documentation pages (/docs, /pricing, /api, /README) return only 'Connect wallet' with no readable content
- —No OpenAPI or schema documentation available for request body or response format
- —The endpoint targets a hardcoded account ID (139); unclear if this is a demo or a real account
- —The broader platform lists many API categories but none have documented schemas
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/accounts/139/balance
- —All APIs on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/accounts/139/balance