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 (account ID 104) behind an x402 paywall. It is part of a broader platform that offers numerous 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 endpoint accepts POST requests and returns JSON. Payment is handled via the x402 protocol: callers must include an X-PAYMENT header with a valid payment proof. The x402 challenge specifies an exact-scheme payment of up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. No API keys or rate limits are advertised; access is gated solely by micropayment.
Documentation on the site is extremely sparse — the docs, pricing, API, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no detailed description of what the balance endpoint actually returns. The endpoint is confirmed live (402 challenge captured), but the lack of documentation makes it difficult to know the exact request format or response structure.
Capabilities
Use cases
- —Querying account balance data for account 104 via a single micropayment
- —Integrating pay-per-call balance checks into agent workflows without API key management
- —Demonstrating x402 protocol micropayment flows on Base
Fit
Best for
- —Developers exploring x402 micropayment protocol integrations
- —Agents needing keyless, pay-per-call API access on Base
- —Quick one-off balance lookups without subscription commitments
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume balance queries where per-call pricing may add up
- —Querying arbitrary account IDs (endpoint is hardcoded to account 104)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/accounts/104/balance \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no request/response examples, and all documentation pages render only a wallet-connect prompt. The specific purpose of this particular endpoint (account 104 balance) is vaguely described.
Warnings
- —No OpenAPI or schema documentation available — request and response formats are unknown
- —All doc/pricing/API/README pages return only a 'Connect wallet' prompt with no content
- —Endpoint is scoped to a single hardcoded account ID (104); unclear if other account IDs are supported
- —No information on what 'balance' data is actually returned
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/accounts/104/balance
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/accounts/104/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
- —The platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com