Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The site hosts a collection of pay-per-request APIs spanning data & analytics, AI/ML inference, finance & Web3 data, and infrastructure utilities, all priced at $0.02 per request and settled in USDC on the Base network.
The specific endpoint `/api/v1/charges/136` is labeled "Premium API Access" in the x402 challenge. It accepts POST requests and returns application/json. The x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 "exact" scheme with a 300-second timeout. No API keys or rate limits are advertised — access is gated purely by per-call USDC micropayment.
Documentation is extremely sparse. The docs, pricing, API, and README pages all render only a "Connect wallet" prompt with no additional content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what this particular endpoint actually returns. The site lists many other endpoints (analytics, AI, finance, utilities) but does not clarify what `/api/v1/charges/136` specifically provides versus those named endpoints. Prospective users should be aware that the actual functionality behind this endpoint is undocumented.
Capabilities
Use cases
- —Agent-initiated API calls paid per-request without pre-registration or API keys
- —Programmatic access to premium data or services settled in USDC on Base
- —Testing x402 payment protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers exploring x402 micropayment-gated APIs
- —AI agents that need keyless, pay-as-you-go API access
- —Users who want to avoid subscriptions and pay only per call
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —Anyone without a Base-network USDC wallet
- —High-volume consumers who would benefit from bulk pricing
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/136 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI spec, no request/response examples, and no clarity on what 'Premium API Access' actually returns. The docs pages are empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —No documentation available — docs, pricing, API, and README pages all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format
- —The specific functionality of /api/v1/charges/136 ('Premium API Access') is undefined — it is not listed among the named endpoints on the homepage
- —Cannot verify what data or service is actually returned after payment
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/charges/136
- —All listed APIs 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 on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/charges/136