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 provides a broad catalog of pay-per-request 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, paid in USDC on the Base network via the x402 protocol.
The specific endpoint `/api/v1/inbox/131` is listed as "Premium API Access" and its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…on Base), which equals $0.02. Payment is made per-call with no API keys, no rate limits, and no minimum commitments required. The x402 challenge specifies a POST method with a 300-second payment timeout.
Note that while the landing page lists many endpoints, the probed endpoint (`/api/v1/inbox/131`) does not correspond to any of the named endpoints on the homepage. Its exact functionality is unclear — it may be a generic inbox or messaging endpoint, or a catch-all premium access route. No OpenAPI schema, detailed documentation, or example request/response payloads were found during crawling. The /api, /pricing, and /README pages all returned only a "Connect wallet" prompt with no substantive content.
Capabilities
Use cases
- —Agents that need on-demand access to AI inference (sentiment, summarization, classification, embeddings) without managing API keys
- —Programmatic retrieval of financial data like token quotes, gas estimates, and exchange rates
- —Utility tasks such as geocoding, data validation, and format conversion via simple HTTP POST calls
- —Building pipelines that pay per request in USDC on Base without subscription overhead
Fit
Best for
- —AI agents and bots that need keyless, pay-as-you-go API access
- —Developers who want to avoid API key management and subscription commitments
- —Crypto-native applications already operating on the Base network
Not for
- —High-volume production workloads where $0.02/request adds up significantly
- —Users who need detailed documentation, SLAs, or guaranteed uptime
- —Applications requiring non-USDC or non-Base payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/131 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no documentation, no example requests or responses, and the specific endpoint path /api/v1/inbox/131 is not explained anywhere on the site. The /api, /pricing, and /README pages are empty behind a wallet gate.
Warnings
- —The endpoint path /api/v1/inbox/131 does not match any named endpoint on the homepage — its actual functionality is unknown.
- —No OpenAPI spec, request schema, or response schema is available.
- —Documentation pages (/api, /pricing, /README) are gated behind a wallet connection and returned no useful content.
- —The platform lists many endpoints on its homepage but none have been individually verified beyond this one probe.
Citations
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on the Base network.https://lowpaymentfee.com
- —The x402 challenge for /api/v1/inbox/131 specifies maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with a 300-second timeout.https://lowpaymentfee.com/api/v1/inbox/131
- —The platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure.https://lowpaymentfee.com