Query FXS token wallet balance via x402 micropayment on Base for $0.02 per request.
What it does
This endpoint at lowpaymentfee.com returns the wallet balance for the FXS (Frax Share) token. It is part of a broader suite of pay-per-call APIs offered by the same provider, spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints on the platform use the x402 payment protocol, settling in USDC on the Base network at a flat rate of $0.02 per request.
The specific endpoint `/api/v1/wallet/FXS/balance` accepts POST requests and returns JSON. The x402 challenge confirms it is live, requiring an exact payment of 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) to the payTo address on Base. No API keys or rate limits are advertised — access is gated purely by the x402 micropayment.
Documentation is extremely sparse. The provider's docs, pricing, API, and README pages all render only a "Connect wallet" prompt with no additional technical detail. There is no OpenAPI schema, no request/response examples, and no description of what fields the balance response contains. The endpoint's actual behavior (e.g., whether you supply a wallet address in the POST body or it returns aggregate data) must be inferred or discovered by paying for a call.
Capabilities
Use cases
- —Querying FXS (Frax Share) token balance for a given wallet address
- —Integrating real-time FXS balance checks into portfolio trackers or bots
- —Agent-driven on-chain balance lookups without API key management
Fit
Best for
- —Developers needing keyless, pay-per-call FXS balance lookups
- —AI agents that can settle x402 micropayments on Base
- —Applications requiring low-friction crypto data without subscriptions
Not for
- —Bulk or high-volume balance queries where $0.02/call adds up quickly
- —Users who need detailed transaction history or multi-token portfolio data
- —Anyone without a Base-compatible USDC wallet for x402 payments
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/wallet/FXS/balance \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{"address": "0xYourWalletAddress"}'Example
Request
{
"address": "0x1234567890abcdef1234567890abcdef12345678"
}Endpoint
Quality
The endpoint is confirmed live via a valid x402 402 challenge with clear pricing. However, documentation is essentially nonexistent — no OpenAPI schema, no request/response examples, and no explanation of accepted parameters or response format. The request body and response JSON shown above are inferred, not documented.
Warnings
- —No OpenAPI or schema documentation available; request/response formats are unknown
- —All non-homepage pages (docs, pricing, API, README) render only 'Connect wallet' with no content
- —Example request JSON is inferred — the actual required POST body is undocumented
- —The endpoint description 'Premium API Access' is generic and does not describe the FXS balance functionality
Citations
- —The endpoint returns HTTP 402 with an x402 challenge requiring 20,000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/wallet/FXS/balance
- —All APIs on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 corresponds to USDC on Basehttps://lowpaymentfee.com/api/v1/wallet/FXS/balance