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 broad catalog of pay-per-request 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 are priced at $0.02 per request, payable in USDC on the Base network with no API keys, no rate limits, and no commitments required.
The specific endpoint `/api/v1/charges/126` is labeled "Premium API Access" and returns a standard x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02. Payment is made via the x402 exact scheme, settling to a specified wallet address with a 300-second timeout. The endpoint accepts HTTP POST and returns application/json.
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 spec, no request/response schema documentation, and no examples of what this particular endpoint actually returns. The landing page lists many API paths but provides no detail on request parameters or response formats. As a result, while the endpoint is confirmed live and the pricing is clear, the actual functionality behind `/api/v1/charges/126` is unknown beyond its label.
Capabilities
Use cases
- —Programmatic access to paid API services without API key management
- —Agent-driven pay-per-call workflows using x402 on Base
- —Accessing data, AI, finance, or utility endpoints with USDC micropayments
Fit
Best for
- —Developers wanting keyless, pay-per-use API access
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume use cases where per-request pricing may add up
- —Anyone requiring fiat-only payment methods
Quick start
# 1. Send a POST to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/charges/126
# 2. Parse the 402 JSON for payment details
# 3. Construct an X-PAYMENT header with a signed USDC payment on Base
# 4. Resend the POST with the header to receive the JSON responseEndpoint
Quality
The endpoint is confirmed live with a valid x402 challenge and clear pricing ($0.02 USDC on Base). However, there is no documentation, no OpenAPI spec, no request/response examples, and the actual functionality of /api/v1/charges/126 is entirely opaque. The docs pages are empty beyond a wallet connect prompt.
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/126 ('Premium API Access') is undefined — it is unclear what data or service it provides
- —No examples of successful responses available
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (USD Coin) on Base with 300-second timeouthttps://lowpaymentfee.com/api/v1/charges/126
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/charges/126
- —Site lists APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com