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 hosts a collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and general utility services. All endpoints are paid per-request using USDC on the Base network via the x402 protocol — no API keys, no rate limits, and no subscriptions required.
The specific endpoint at `/api/v1/inbox/145` is listed as "Premium API Access" and accepts POST requests. Its x402 challenge advertises a maximum cost of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 per call (USDC uses 6 decimals). The platform's landing page confirms a uniform $0.02/request pricing across all listed endpoints.
The broader platform advertises endpoints for metrics, reports, data export, insights, sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation. However, no OpenAPI schema, detailed documentation, or example request/response payloads are available for any of these endpoints, including the inbox/145 endpoint. The purpose of the "inbox/145" path specifically is unclear — it does not map to any of the named endpoints on the landing page.
Capabilities
Use cases
- —Accessing paid API services without creating accounts or managing API keys
- —Making one-off API calls with instant USDC micropayments on Base
- —Integrating pay-per-use endpoints into agent workflows via x402
Fit
Best for
- —Developers wanting zero-friction, keyless 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 OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk/subscription pricing
- —Developers who cannot transact in USDC on Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/inbox/145 \
-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 documentation, no OpenAPI schema, no example requests or responses, and the specific purpose of /api/v1/inbox/145 is undocumented. The crawled pages beyond the landing page returned only wallet-connect prompts with no useful content.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The path /api/v1/inbox/145 does not correspond to any named endpoint on the landing page — its specific function is unknown
- —No example request or response payloads are documented
- —Crawled /api, /pricing, and /README pages returned no meaningful content (only 'Connect wallet')
Citations
- —Uniform pricing of $0.02 per request across all endpointshttps://lowpaymentfee.com
- —No API keys, no rate limits, instant access, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/inbox/145
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/inbox/145