x402-payable account balance API on Base, settling in USDC at $0.02 per request.
What it does
This endpoint at lowpaymentfee.com provides a per-call paid API for retrieving account balance information (specifically account ID 15). It uses the x402 payment protocol, settling on the Base network in USDC. The endpoint returns HTTP 402 with a payment challenge when called without a valid X-PAYMENT header, and serves the response after payment is confirmed.
The specific endpoint `/api/v1/accounts/15/balance` is part of a broader platform that advertises multiple API categories including Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure utilities — all priced at $0.02 per request. The platform emphasizes a no-API-key, no-rate-limit, pay-per-use model with instant access. The x402 challenge confirms the price: maxAmountRequired of 20000 base units of USDC (6 decimals) equals $0.02.
Documentation is extremely sparse. The docs, API, pricing, 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 description of what the balance endpoint actually returns beyond its name. The endpoint is live and responds correctly with a 402 challenge, but the lack of documentation makes it difficult to know what input the POST body expects or what the response payload looks like.
Capabilities
Use cases
- —Retrieving account balance data via a single paid API call
- —Demonstrating x402 payment protocol integration on Base
- —Agent-driven balance lookups without API key management
Fit
Best for
- —Developers exploring x402 payment protocol integrations
- —Agents needing keyless, pay-per-call balance queries
- —Projects already operating on the Base network with USDC
Not for
- —Production use requiring documented request/response schemas
- —High-volume balance lookups where per-call fees add up
- —Users who need detailed API documentation before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/accounts/15/balance
# Returns 402 with x402 payment challenge.
# Include a valid X-PAYMENT header (x402 protocol) to receive the balance response.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is no documentation, no OpenAPI schema, no request/response examples, and the docs pages are empty. The purpose of this specific endpoint (account 15 balance) is unclear and undocumented.
Warnings
- —No API documentation available — docs, pricing, and README pages all show only 'Connect wallet'
- —No OpenAPI or schema describing request body or response format
- —The specific endpoint /api/v1/accounts/15/balance is not listed on the homepage's available APIs, making its purpose unclear
- —No information on what 'account 15' refers to or what balance data is returned
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/accounts/15/balance
- —The platform advertises $0.02 per request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/accounts/15/balance
- —Docs, API, pricing, and README pages render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs