x402-gated API platform on Base offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-protocol API marketplace that gates a variety of endpoints behind per-request micropayments settled in USDC on the Base network. The specific endpoint at `/api/v1/inbox/165` is listed as "Premium API Access" and costs up to $0.02 per call (maxAmountRequired of 20,000 base units of USDC, which has 6 decimals = $0.02). No API keys or rate limits are required; callers simply attach an x402 payment header to each request.
The broader platform advertises four categories of APIs: 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 listed at the same $0.02/request price point. The platform accepts USDC (contract 0x8335…2913) on Base and pays out to a single wallet address.
Note that the specific functionality behind `/api/v1/inbox/165` is not documented beyond the generic "Premium API Access" label. There is no OpenAPI schema, no request/response examples, and the crawled docs pages (pricing, README, API) all resolve to a minimal "Connect wallet" page with no additional detail. The endpoint is confirmed live (returns a valid 402 challenge), but what it actually returns upon successful payment is unknown.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API keys
- —Fetching real-time financial data such as token quotes, exchange rates, and gas estimates
- —Running data analytics queries and exporting reports on a pay-per-use basis
- —Geocoding and data validation via utility endpoints
Fit
Best for
- —Agents or developers who want key-free, pay-per-request API access
- —x402-compatible clients that can settle micropayments in USDC on Base
- —Low-volume or bursty workloads where $0.02/request is cost-effective
Not for
- —High-volume production workloads where per-request costs add up quickly
- —Users who need detailed API documentation, SLAs, or guaranteed uptime
- —Developers without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/165 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, but there is no OpenAPI schema, no request/response examples, and no documentation beyond a generic label. The crawled pages beyond the homepage are empty ('Connect wallet'). The actual functionality of /api/v1/inbox/165 is entirely unknown.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —The specific functionality of /api/v1/inbox/165 ('Premium API Access') is undocumented — it is unclear what data or service it provides
- —Docs pages (/pricing, /README, /api) returned no useful content beyond 'Connect wallet'
- —No request body schema or response schema is available; callers cannot know what to send or expect back
- —The platform lists many endpoint categories but none have detailed documentation
Citations
- —The endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/165
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/inbox/165
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers APIs in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com