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" resource at the path `/api/v1/accounts/55/balance`. It is part of a broader platform that offers dozens of x402-gated API endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services — all payable per-request in USDC on the Base network with no API keys or rate limits required.
The specific endpoint probed (`/api/v1/accounts/55/balance`) returns an x402 challenge requesting up to 20,000 base units of USDC (0.02 USD) per call, consistent with the site's advertised flat $0.02/request pricing. Payment is settled on-chain via the "exact" scheme to address `0x1A2B…85F3`, using the canonical Base USDC contract (`0x8335…2913`). The challenge specifies a 300-second payment timeout and declares the output MIME type as `application/json`.
Documentation is extremely thin — the docs, pricing, API, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema, and no explanation of what the balance endpoint actually returns or what parameters it accepts. The endpoint name suggests it retrieves an account balance for account ID 55, but this is purely inferred from the URL path. Without documentation or example responses, the actual behavior and data model remain unknown.
Capabilities
Use cases
- —Querying account balance data behind a per-call USDC paywall
- —Demonstrating x402 payment protocol integration on Base
- —Agent-driven micropayment API consumption without API keys
Fit
Best for
- —Developers experimenting with x402 payment flows
- —Agents that can settle USDC payments on Base L2
- —Use cases needing keyless, pay-per-request API access
Not for
- —Production workloads requiring documented request/response schemas
- —Users who need fiat or non-crypto payment options
- —High-volume use cases where per-call pricing is inefficient
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/accounts/55/balance
# Returns 402 with x402 challenge; attach X-PAYMENT header with signed USDC payment (0.02 USD on Base) to access.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is zero documentation: no OpenAPI spec, no request/response schema, no examples, and no explanation of what the endpoint actually does beyond its URL path. The docs pages are empty stubs.
Warnings
- —No documentation available — docs, pricing, API, and README pages all show only 'Connect wallet' with no content.
- —No request or response schema provided; the actual data returned by this endpoint is unknown.
- —The endpoint path '/api/v1/accounts/55/balance' appears to be a hardcoded account ID (55); unclear if this is a demo or a real resource.
- —No OpenAPI spec or ai-plugin manifest found.
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USD) on Base network.https://lowpaymentfee.com/api/v1/accounts/55/balance
- —The platform advertises $0.02/request flat pricing with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.https://lowpaymentfee.com/api/v1/accounts/55/balance
- —Docs, pricing, API, and README pages render only a 'Connect wallet' prompt with no additional content.https://lowpaymentfee.com/docs