Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that exposes a broad catalog of endpoints across four categories: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text 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 via the x402 protocol.
The specific endpoint `/api/v1/inbox/106` is listed as "Premium API Access" and returns a valid 402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base. Payment is made via the x402 exact scheme with no API keys or rate limits required. The payment address is `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` and the asset contract is the canonical Base USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`). The timeout for payment is 300 seconds.
Documentation is minimal — the landing page lists available endpoints and pricing but provides no request/response schemas, parameter descriptions, or usage examples. The `/api`, `/pricing`, and `/README` pages all resolve to a "Connect wallet" prompt with no additional content. The exact functionality behind the `/api/v1/inbox/106` path is unclear; it does not correspond to any of the named endpoints on the landing page. Without schemas or documentation, callers will need to experiment to determine accepted request bodies and response formats.
Capabilities
Use cases
- —Agent-driven data retrieval without API key management
- —On-demand AI inference (sentiment, summarization, classification, embeddings) paid per call
- —Fetching real-time crypto gas estimates or token quotes via micropayment
- —Geocoding or data validation as a utility microservice
Fit
Best for
- —AI agents needing keyless, pay-per-use API access
- —Developers prototyping with low-cost, no-commitment endpoints
- —Web3-native applications that can settle USDC on Base
Not for
- —High-volume production workloads needing SLAs and guaranteed uptime
- —Users who need detailed API documentation and typed schemas before integrating
- —Applications requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/106 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, there is no OpenAPI schema, no request/response documentation, no examples, and the specific /api/v1/inbox/106 path is not described on the landing page. The /api, /pricing, and /README pages are empty beyond a wallet prompt. This is effectively a stub listing.
Warnings
- —The path /api/v1/inbox/106 does not match any named endpoint on the landing page; its exact functionality is unknown.
- —No request or response schemas are available — callers must guess at accepted payloads.
- —Documentation pages (/api, /pricing, /README) contain no useful content beyond 'Connect wallet'.
- —No rate limit, SLA, or uptime guarantees are documented.
Citations
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —The x402 challenge for /api/v1/inbox/106 requests up to 20,000 base units of USDC (USD Coin) on Base with a 300-second timeout.https://lowpaymentfee.com/api/v1/inbox/106
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.https://lowpaymentfee.com/api/v1/inbox/106
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure.https://lowpaymentfee.com