Pay-per-call ACH endpoint on Base via x402 — $0.02/request in USDC, no API keys required.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints gated by the x402 protocol on the Base network. This specific endpoint (`/api/v1/ach/4`) is listed as "Premium API Access" and accepts POST requests. Payment is settled in USDC (contract 0x8335…2913 on Base) at a maximum cost of 20,000 base units, which equals $0.02 per call (USDC uses 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an x402 payment header to each request.
The broader lowpaymentfee.com platform advertises endpoints across several categories: 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 are priced at $0.02 per request.
Documentation is extremely sparse. The `/docs`, `/api`, `/pricing`, and `/README` pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The exact functionality behind the `/api/v1/ach/4` path is unclear — the name "Premium API Access" and the `ach` path segment suggest it may relate to ACH (Automated Clearing House) payment processing, but this cannot be confirmed from the available material.
Capabilities
Use cases
- —Programmatic access to a premium API endpoint without managing API keys or subscriptions
- —Agent-driven workflows that need on-demand, per-call payment settlement on Base
- —Exploring x402-gated services with minimal upfront commitment
Fit
Best for
- —Developers or agents wanting zero-signup, pay-as-you-go API access
- —x402-compatible wallets and agent frameworks on the Base network
- —Low-volume or sporadic usage where per-call pricing is cost-effective
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume consumers who would benefit from bulk pricing or subscription models
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/ach/4 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and well-formed, confirming the endpoint exists and its pricing. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and the actual functionality of /api/v1/ach/4 is undocumented. This is effectively a stub listing.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README all return only a 'Connect wallet' prompt with no technical content.
- —No OpenAPI or schema definition found; request and response formats are unknown.
- —The purpose of /api/v1/ach/4 ('Premium API Access') is unclear — the 'ach' path suggests ACH payment processing but this is unconfirmed.
- —The platform lists many endpoint categories (AI, finance, analytics, infrastructure) but provides no evidence of actual underlying functionality.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/ach/4
- —All endpoints are priced at $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/ach/4
- —Documentation pages (/docs, /api, /pricing, /README) render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs