x402-gated account balance endpoint on Base, paying $0.02 per request in 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/100/balance` is one of many endpoints offered by the lowpaymentfee.com platform, which advertises a broad catalog spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities — all gated behind x402 micropayments on the Base network.
The x402 challenge confirms the endpoint is live and accepts POST requests. Payment is settled in USDC (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913` on Base) using the "exact" scheme. The `maxAmountRequired` is 20000 base units, which at 6 decimals equals $0.02 per request — consistent with the site's advertised flat pricing of $0.02/request across all endpoints. No API keys are required; access is granted purely via the x402 payment header. The platform claims no rate limits and instant access.
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 response actually contains. The endpoint path suggests it returns a balance for account ID 100, but the semantics (financial balance, credit balance, token balance, etc.) are not documented. The broader platform lists many endpoint categories but provides no detail on any of them beyond names and prices.
Capabilities
Use cases
- —Querying account balance data with per-request USDC micropayments
- —Integrating x402-compatible agents that pay per API call on Base
- —Testing x402 payment flows against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that need pay-per-call API access without API keys
- —Low-volume or sporadic API consumers who prefer no subscriptions
Not for
- —Users needing well-documented API contracts with full schemas
- —High-volume consumers who need bulk pricing or rate guarantees
- —Anyone requiring detailed documentation before integration
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/accounts/100/balance \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but documentation is essentially nonexistent — no OpenAPI schema, no request/response examples, and no explanation of what the endpoint actually returns. The broader site lists many endpoints but provides zero detail on any of them.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content
- —No OpenAPI or request/response schema provided; endpoint behavior must be discovered empirically
- —The specific endpoint path (/api/v1/accounts/100/balance) is not listed on the site's landing page, raising questions about whether it is a production resource or a demo/test endpoint
- —The platform lists many endpoint categories (AI, analytics, finance, etc.) but none have any documented behavior
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/accounts/100/balance
- —The platform advertises $0.02/request flat 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/100/balance