Pay-per-call API platform on Base via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across data analytics, AI/ML inference, finance/Web3, and utility services. All endpoints are settled on the Base network using USDC, with a uniform price of $0.02 per request. The x402 protocol eliminates the need for API keys, accounts, or rate limits — callers simply attach a payment header to each request.
The specific endpoint at `/api/v1/payments/389` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base. The payment is made to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using the exact payment scheme. The endpoint accepts POST requests and returns `application/json`.
The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation — all at the same $0.02 price point. However, documentation beyond the landing page is extremely sparse (docs, pricing, and API pages all render only a "Connect wallet" prompt), so the actual functionality and response schemas of these endpoints are not verifiable from the crawl material.
Capabilities
Use cases
- —Agents needing on-demand API access without pre-registration or API keys
- —Programmatic access to utility or data endpoints with per-call crypto payment
- —Testing x402 payment flows on Base with low-cost endpoints
Fit
Best for
- —Developers or agents wanting zero-signup API access via x402
- —Low-cost per-request usage without subscriptions or commitments
- —Base/USDC-native workflows needing simple pay-as-you-go endpoints
Not for
- —Users who need detailed API documentation or response schema guarantees before calling
- —High-volume use cases where $0.02/request adds up and bulk pricing would be preferred
- —Users without USDC on Base or unfamiliar with x402 payment protocol
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/389 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, there is no OpenAPI schema, no documentation of request/response formats, and the docs/pricing/API pages are all blank beyond a wallet connect prompt. The actual functionality behind 'Premium API Access' at /api/v1/payments/389 is not described anywhere. This is effectively a stub listing.
Warnings
- —No documentation available — docs, pricing, and API pages all render only 'Connect wallet'
- —The specific functionality of /api/v1/payments/389 ('Premium API Access') is not described anywhere on the site
- —No request or response schema is documented; callers cannot know what to send or expect back
- —No OpenAPI spec or machine-readable API description found
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 USDC on Base (= $0.02)https://lowpaymentfee.com/api/v1/payments/389
- —Payment address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3https://lowpaymentfee.com/api/v1/payments/389
- —USDC asset contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/payments/389