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 settled in USDC on the Base network. The specific endpoint at `/api/v1/messages/137` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an x402 payment header to each request.
The 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 listed endpoints share the same $0.02 per-request pricing.
The probed endpoint (`/api/v1/messages/137`) returned a valid x402 challenge with version 1, confirming it is live. It accepts POST requests and returns `application/json`. However, the specific functionality behind the "messages/137" path is not documented on the landing page — the crawled site lists other endpoint categories but does not mention a messages API. There is no OpenAPI spec, no detailed request/response documentation, and the pricing, README, and API pages behind the site require a wallet connection to view, so deeper documentation could not be retrieved.
Capabilities
Use cases
- —Accessing data analytics and reporting endpoints without subscription commitments
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) on a per-call basis
- —Fetching real-time financial data such as token prices, exchange rates, and gas estimates
- —Using utility services like geocoding, validation, and data conversion with instant crypto payment
Fit
Best for
- —Developers who want instant API access without signup or API key management
- —Agents and bots that can settle micropayments in USDC on Base
- —Projects needing low-cost, pay-as-you-go access to diverse API categories
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —Applications requiring high-throughput bulk access at volume-discounted pricing
- —Teams that cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/messages/137 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no OpenAPI spec, no request/response schema, no documentation for the specific /messages/137 path, and the crawled pages beyond the landing page were gated behind wallet connection. The purpose of this particular endpoint is unclear.
Warnings
- —The /api/v1/messages/137 endpoint is not listed among the documented APIs on the landing page — its specific functionality is unknown.
- —No OpenAPI specification or request/response schema is available.
- —Pricing, README, and API documentation pages require wallet connection and could not be crawled.
- —No example requests or responses are available to verify actual behavior.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/messages/137
- —All listed endpoints are priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —The platform offers Data & Analytics, AI & ML, Finance & Web3, and Infrastructure API categorieshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/messages/137