Pay-per-call ACH endpoint on Base via x402 — $0.02/request in USDC, no API keys required.
What it does
This endpoint at `/api/v1/ach/55` is part of the lowpaymentfee.com platform, which offers a collection of pay-per-request APIs spanning data analytics, AI/ML inference, finance, crypto, and utility services. All endpoints use the x402 payment protocol, settling in USDC on the Base network. The specific function of the `/api/v1/ach/55` path is not documented — the provider labels it generically as "Premium API Access" — so its exact purpose is unclear. It may relate to ACH (Automated Clearing House) banking data or operations given the URL path, but this is speculative.
The endpoint is live and returns a valid x402 challenge. Pricing is $0.02 per request (20,000 base units of USDC with 6 decimals = $0.02), consistent with the site-wide flat rate advertised on the landing page. Payment is made via the x402 `exact` scheme to a specified wallet address on Base. No API keys, rate limits, or subscriptions are required — callers simply attach an `X-PAYMENT` header with a valid payment proof.
Documentation is extremely sparse. The `/docs`, `/api`, `/pricing`, and `/README` pages all render only a "Connect wallet" prompt with no additional content. There is no OpenAPI spec, no request/response schema, and no usage examples available. The lack of documentation for this specific endpoint makes it difficult to determine what inputs it expects or what data it returns.
Capabilities
Use cases
- —Accessing ACH-related data or operations on a per-call basis without subscription
- —Integrating pay-per-request financial endpoints into agent workflows
- —Testing x402 payment protocol integrations with a low-cost endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents needing low-cost per-call API access without credentials
- —Use cases requiring USDC micropayments on Base
Not for
- —Production workloads requiring well-documented, stable APIs
- —Users who need detailed request/response schemas before integration
- —High-volume use cases where per-request pricing is inefficient
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/ach/55 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is essentially no documentation: no OpenAPI spec, no request/response schema, no examples, and no explanation of what '/api/v1/ach/55' actually does. The docs pages are empty. This is effectively a stub listing.
Warnings
- —The specific function of /api/v1/ach/55 is undocumented — 'Premium API Access' is a generic label applied across the platform
- —All documentation pages (/docs, /api, /pricing, /README) return only a 'Connect wallet' prompt with no useful content
- —No request or response schema is available; callers cannot know what inputs are expected or what outputs are returned
- —The 'ach' path segment suggests possible financial/banking operations which may be subject to regulatory requirements
- —This endpoint does not appear in the site's own listed API catalog, raising questions about its status
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 in USDC on Basehttps://lowpaymentfee.com/api/v1/ach/55
- —Site-wide pricing is $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/ach/55