Check OP token wallet balance on Base via x402 micropayment — $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com returns wallet balance information for the OP (Optimism) 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, 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/OP/balance` accepts POST requests and returns JSON. Based on the URL structure, it likely expects a wallet address as input and returns the OP token balance for that address. The x402 challenge confirms the endpoint is live, advertising a maxAmountRequired of 20,000 base units of USDC (6 decimals), which equals $0.02. Payment is made to address 0x1A2B...85F3 on Base using the USDC contract 0x8335...2913.
Documentation on the site is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no detailed parameter documentation available. The endpoint's exact input format and response structure must be inferred from the URL pattern alone.
Capabilities
Use cases
- —Querying the OP token balance of a specific wallet address
- —Building portfolio trackers that need on-demand balance lookups
- —Automating balance checks in trading or DeFi workflows
Fit
Best for
- —Agents needing quick, keyless OP token balance lookups
- —Applications that prefer pay-per-call over subscription API keys
- —Developers building on Base who want x402-native payment flows
Not for
- —Bulk or high-frequency balance polling (no documented rate limits but $0.02/call adds up)
- —Querying balances for tokens other than OP (endpoint is OP-specific)
- —Users who need detailed documentation or guaranteed SLAs
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/wallet/OP/balance \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_header>" \
-d '{"address": "0xYourWalletAddress"}'Example
Request
{
"address": "0x1234567890abcdef1234567890abcdef12345678"
}Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing. However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI schema, no request/response examples, and the input format is entirely inferred from the URL pattern. The endpoint's actual behavior and response structure are unknown.
Warnings
- —No documentation available — all doc/pricing/API pages render only 'Connect wallet'
- —No OpenAPI or schema definition found
- —Request body format and response structure are inferred, not documented
- —The example_request_json is speculative based on URL pattern
Citations
- —The endpoint returns HTTP 402 with x402 challenge advertising 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/wallet/OP/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
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/wallet/OP/balance