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, settled in USDC on the Base network.
The specific endpoint `/api/v1/payments/295` is labeled "Premium API Access" and returns a live x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals). Payment is made via the x402 exact scheme to a specified wallet address. The endpoint accepts POST requests and returns application/json. 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 further content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what this particular endpoint actually returns. The site's landing page lists many API paths but provides no detail on request parameters or response formats. Without documentation it is unclear what data or functionality the `/api/v1/payments/295` endpoint specifically provides beyond its generic "Premium API Access" label.
Capabilities
Use cases
- —Accessing premium data or services with per-call USDC micropayments on Base
- —Agent-driven API consumption without pre-registration or API keys
- —Demonstrating x402 payment protocol integration
Fit
Best for
- —Developers experimenting with x402 micropayment protocol
- —Agents that can settle USDC payments on Base L2
- —Use cases requiring keyless, pay-as-you-go API access
Not for
- —Users needing well-documented API contracts with clear request/response schemas
- —Production workloads requiring SLAs, rate-limit guarantees, or support
- —Users without a Base-compatible USDC wallet
Quick start
# 1. Send a POST to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/payments/295
# 2. Parse the 402 response, construct an x402 payment header
# with 20000 base-unit USDC on Base, then resend:
curl -X POST https://lowpaymentfee.com/api/v1/payments/295 \
-H "X-PAYMENT: <signed-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but documentation is effectively nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schema, and no description of what 'Premium API Access' actually returns. The listing is essentially a stub.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format
- —The specific purpose of /api/v1/payments/295 ('Premium API Access') is unclear and may be a generic or placeholder endpoint
- —Cannot verify what data or service is actually delivered after payment
Citations
- —The endpoint returns a live x402 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/payments/295
- —All APIs are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The site offers APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/payments/295