Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The site hosts a collection of pay-per-request APIs spanning data & analytics, AI/ML inference, finance & Web3 data, and infrastructure utilities — all priced at $0.02 per request settled in USDC on the Base network.
The specific endpoint `/api/v1/transactions/27` is listed under the site's premium access tier. It accepts POST requests and requires an X-PAYMENT header containing a valid x402 payment proof. The maximum amount required is 20,000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base, 6 decimals), which equals $0.02 USD per call. There are no API keys, no rate limits, and no subscription commitments — access is purely pay-per-use.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional technical detail. The exact response format and functionality of this particular `/transactions/27` endpoint is not documented beyond the generic "Premium API Access" label. Without further documentation it is unclear what data or service this specific endpoint returns.
Capabilities
Use cases
- —Accessing premium data or services without subscription or API key management
- —Agent-driven pay-per-call workflows settled on-chain in USDC
- —Programmatic access to gated resources using x402 payment headers
Fit
Best for
- —Developers wanting zero-commitment pay-per-use API access
- —AI agents with x402-compatible wallets on Base
- —Users who prefer on-chain micropayments over traditional billing
Not for
- —Users needing detailed API documentation before integrating
- —High-volume use cases where per-request pricing at $0.02 adds up significantly
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/27 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is virtually no documentation about what this endpoint actually does, what inputs it accepts, or what it returns. The docs pages are empty beyond a wallet-connect prompt.
Warnings
- —No documentation available — docs/pricing/README pages only show 'Connect wallet'
- —The exact functionality of /api/v1/transactions/27 is unknown; 'Premium API Access' is the only descriptor
- —No OpenAPI schema, no example responses, no input schema beyond POST method
- —Cannot verify what data or service is actually delivered after payment
Citations
- —Endpoint returns 402 with x402 challenge requiring 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/27
- —Site advertises $0.02/request pricing with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/27