x402-gated account balance endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com provides a "Premium API Access" account balance lookup via the x402 payment protocol. It is one of many endpoints offered by the lowpaymentfee.com platform, which advertises a suite of APIs spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities — all gated behind x402 micropayments settled in USDC on the Base network.
The specific endpoint `/api/v1/accounts/138/balance` accepts POST requests and returns JSON. The x402 challenge indicates a maximum cost of 20,000 base units of USDC (0x8335…2913 on Base), which at 6 decimals equals $0.02 per request. The platform advertises uniform $0.02/request pricing across all its endpoints, with no API keys, no rate limits, and no minimum commitments required. Payment is made inline via the X-PAYMENT header per the x402 protocol.
Documentation is extremely sparse. The /docs, /api, /pricing, and /README pages all returned only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what the "account balance" endpoint actually returns or what parameters it accepts. The endpoint is confirmed live (402 challenge captured), but the lack of documentation makes it difficult to assess the actual utility or data returned.
Capabilities
Use cases
- —Querying account balance information via a pay-per-call model
- —Integrating x402 micropayment-gated endpoints into agent workflows
- —Demonstrating x402 protocol usage with USDC on Base
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that need pay-per-call API access without API key management
- —Low-volume queries where $0.02/request is acceptable
Not for
- —Production use cases requiring documented request/response schemas
- —High-volume batch queries where per-call pricing is cost-prohibitive
- —Users who need detailed API documentation before integration
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/accounts/138/balance \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no request/response examples, and all documentation pages return only 'Connect wallet' with no content. The purpose of the specific 'accounts/138/balance' endpoint is unclear beyond its name.
Warnings
- —No documentation available — all doc pages return only 'Connect wallet'
- —No OpenAPI or request/response schema provided
- —Purpose and parameters of /api/v1/accounts/138/balance are undocumented
- —The endpoint path includes a hardcoded account ID (138), suggesting it may be specific to a single account rather than a general-purpose API
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/accounts/138/balance
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/accounts/138/balance