x402-gated account balance endpoint on Base, pay-per-call with 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/37/balance` is gated behind a per-request USDC payment on the Base network. The x402 challenge indicates a maximum cost of 20,000 base units of USDC (0.02 USD per request), consistent with the provider's site-wide $0.02/request pricing model.
The provider, lowpaymentfee.com, hosts a broader suite of pay-per-call APIs spanning data & analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints appear to use the same x402 exact-payment scheme on Base with USDC at $0.02 per call. The platform advertises no API keys, no rate limits, and instant access.
This particular endpoint (`/accounts/37/balance`) is labeled "Premium API Access" but its actual functionality appears to be an account balance query. Documentation beyond the landing page is extremely thin — 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 detailed documentation available. The endpoint is confirmed live via a valid 402 challenge response.
Capabilities
Use cases
- —Querying account balance information via a single paid API call
- —Integrating pay-per-call balance lookups into agent workflows
- —Demonstrating x402 payment protocol integration on Base
Fit
Best for
- —Developers experimenting with x402 payment-gated APIs
- —Agents needing simple per-call balance data without API key management
- —Projects requiring USDC micropayment-settled endpoints on Base
Not for
- —Production use cases requiring documented request/response schemas
- —High-volume balance queries where per-call pricing is inefficient
- —Users who need detailed API documentation or support
Quick start
# 1. POST to the endpoint — you'll get a 402 with payment challenge
curl -X POST https://lowpaymentfee.com/api/v1/accounts/37/balance
# 2. Pay the x402 challenge (0.02 USDC on Base) and include the
# X-PAYMENT header with your signed payment proof to get the response.Endpoint
Quality
The endpoint is confirmed live via a valid x402 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no request/response examples, and all documentation pages render only 'Connect wallet' with no content. The endpoint's actual functionality ('accounts/37/balance') is unclear and undocumented.
Warnings
- —No API documentation available — docs, pricing, and README pages all show only 'Connect wallet'
- —No OpenAPI or request/response schema provided
- —The endpoint path references a hardcoded account ID (37); unclear if this is parameterizable
- —Actual response format and fields are unknown — no examples exist in crawled material
- —The 'Premium API Access' label is generic and does not describe the endpoint's real function
Citations
- —The x402 challenge requires a maximum of 20,000 base units of USDC (USD Coin) on Base networkhttps://lowpaymentfee.com/api/v1/accounts/37/balance
- —Site-wide pricing is $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The provider offers APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com