x402-gated API platform on Base offering data, AI, finance, and utility endpoints at $0.02/request via USDC.
What it does
lowpaymentfee.com is an x402-protocol API marketplace that gates a broad set of endpoints behind per-request USDC micropayments on the Base network. The specific endpoint at `/api/v1/inbox/164` is listed as "Premium API Access" and accepts POST requests, charging up to 20,000 base units of USDC (i.e., $0.02 per call, since USDC uses 6 decimals). Payment is settled on-chain to the specified wallet address, with no API keys, rate limits, or subscriptions required.
The provider's landing page 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 listed endpoints share the same $0.02/request pricing. However, the specific functionality behind the `/api/v1/inbox/164` path is not documented — the description simply says "Premium API Access" without detailing what data or service it returns.
The endpoint is live and returns a valid x402 challenge (HTTP 402) with version 1 of the protocol. The payment scheme is "exact" on the Base network using the canonical USDC contract (0x8335…). No OpenAPI schema, detailed request/response documentation, or usage examples were found in the crawl. The `/api`, `/pricing`, and `/README` pages all returned only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Paying per-request for API access without subscriptions or API keys
- —Integrating on-chain USDC micropayments into automated agent workflows
- —Accessing data, AI, finance, or utility endpoints via x402 protocol
Fit
Best for
- —Agents or developers wanting zero-commitment, pay-as-you-go API access
- —x402-compatible clients that can sign USDC payments on Base
- —Use cases where $0.02/request pricing is cost-effective
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume batch workloads where per-request micropayments add overhead
- —Users without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/164 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but the specific functionality of /api/v1/inbox/164 is completely undocumented. No OpenAPI schema, no request/response examples, and no description beyond the generic 'Premium API Access' label. The crawled pages beyond the homepage returned only 'Connect wallet' with no useful content.
Warnings
- —The specific functionality of /api/v1/inbox/164 is unknown — 'Premium API Access' is not descriptive
- —No OpenAPI spec, request schema, or response schema available
- —No documentation pages rendered useful content (all showed only 'Connect wallet')
- —Cannot verify what data or service this endpoint actually provides
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/164
- —All listed endpoints are priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —The USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/inbox/164
- —The platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com