Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint at `/api/v1/transactions/254` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) per call. No API keys or rate limits are required; callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform advertises multiple API categories including 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.
However, the specific functionality behind `/api/v1/transactions/254` is not documented beyond the label "Premium API Access." The docs, pricing, and README pages all resolve to a minimal "Connect wallet" prompt with no further technical documentation, schemas, or example payloads. Without paying and calling the endpoint, the actual response format and data returned remain unknown.
Capabilities
Use cases
- —Accessing premium data or transaction information via a single micropayment
- —Integrating pay-per-use API calls into agent workflows without managing API keys
- —Testing x402 protocol payment flows on Base network
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents needing keyless, pay-per-call API access
- —Low-volume consumers who prefer per-request pricing over subscriptions
Not for
- —Users needing detailed API documentation or guaranteed SLAs before purchasing
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Anyone requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/254 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, there is no documentation, no OpenAPI schema, no example requests or responses, and the actual functionality behind 'Premium API Access' at /api/v1/transactions/254 is entirely opaque. The docs/pricing/README pages are all empty beyond a wallet connect prompt.
Warnings
- —The specific functionality of /api/v1/transactions/254 is undocumented — 'Premium API Access' is the only description available.
- —No OpenAPI spec, request schema, or response schema is provided anywhere on the site.
- —All documentation pages (docs, pricing, README, api) resolve to a minimal 'Connect wallet' page with no useful content.
- —The broader platform lists many API categories (AI, finance, analytics, infrastructure) but none have visible documentation — it is unclear whether they are fully operational.
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC ($0.02) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/254
- —The platform lists endpoints at $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/transactions/254
- —API categories include Data & Analytics, AI & ML, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com