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/155` is labeled "Premium API Access" in its x402 challenge. The challenge advertises a maxAmountRequired of 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913, which has 6 decimals), equating to $0.02 per call. Payment is made via the x402 exact scheme — callers attach an X-PAYMENT header with a signed payment to the payTo address. No API keys or rate limits are advertised; access is gated purely by per-request micropayment.
Documentation is extremely sparse. The docs, pricing, API, 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 description of what data or functionality this particular charge endpoint returns. The landing page lists sibling endpoints (sentiment analysis, summarization, geocoding, price feeds, etc.) but does not clarify what `/api/v1/charges/155` specifically provides. Prospective callers should be aware that the actual response payload and accepted request body are undocumented.
Capabilities
Use cases
- —Accessing premium data or services with per-request USDC micropayments on Base
- —Agent-driven API consumption without API keys or subscriptions
- —Testing x402 payment protocol integrations
Fit
Best for
- —Developers experimenting with x402 micropayment flows
- —Agents that need keyless, pay-as-you-go API access on Base
- —Projects wanting to avoid subscription commitments for occasional API calls
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/155 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <signed-x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts payments. However, there is no documentation, no OpenAPI schema, no request/response examples, and no explanation of what this specific endpoint actually returns. The listing is effectively a stub with only pricing and protocol details available.
Warnings
- —No documentation available — docs, pricing, API, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or output schema describing what the endpoint returns or what request body it expects.
- —The purpose of /api/v1/charges/155 ('Premium API Access') is completely unspecified — it is unclear what data or service is provided.
- —Sibling endpoints listed on the homepage (AI, analytics, finance, utils) are at different paths and may not share behavior with this charge endpoint.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/charges/155
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 (6 decimals), making 20000 base units equal to $0.02https://lowpaymentfee.com/api/v1/charges/155
- —The site advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Docs, pricing, API, and README pages render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs