Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, paid in USDC on the Base network with no API keys, no rate limits, and no commitments required. The x402 protocol handles payment inline: callers attach a payment header and the server fulfills the request upon verification.
The specific endpoint at `/api/v1/transactions/229` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The endpoint accepts POST requests and returns application/json. Beyond this particular endpoint, the platform advertises categories including sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, gas estimates, geocoding, validation, conversion, and data export — all at the same $0.02 price point.
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 example payloads available. The actual functionality behind "Premium API Access" at this specific transaction endpoint is unclear — it may be a generic transaction record or a demonstration endpoint. Without documentation or schema details, callers must discover behavior experimentally.
Capabilities
Use cases
- —Accessing pay-per-call API endpoints without traditional API key registration
- —Making one-off API requests paid in USDC on Base L2
- —Programmatic agent-driven API consumption with inline crypto payments
Fit
Best for
- —Developers wanting zero-signup, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing detailed API documentation or guaranteed SLAs
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Developers without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/229 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schema, and no explanation of what 'Premium API Access' at /api/v1/transactions/229 actually returns. The listing is effectively a stub.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet'
- —No OpenAPI or schema specification found
- —The purpose and response format of /api/v1/transactions/229 ('Premium API Access') is undocumented and unclear
- —Cannot verify what data or service this specific endpoint provides
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge requests maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/229
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com