USD/SGD forex rate via x402 micropayment on Base for $0.02 per request.
What it does
This endpoint provides the USD/SGD foreign exchange rate, accessible through the x402 payment protocol on the Base network. Each request costs $0.02 (20,000 base units of USDC with 6 decimals) and requires no API keys, rate limits, or upfront commitments — you pay per call using USDC on Base.
The endpoint is part of a broader suite of APIs offered by lowpaymentfee.com, which spans data analytics, AI/ML inference, finance/crypto market data, and utility services, all priced uniformly at $0.02 per request. The forex endpoint specifically serves the USDSGD currency pair, returning JSON. The x402 challenge confirms the endpoint is live, accepts POST requests, and settles payments to a specified Ethereum address on the Base L2 network.
Documentation beyond the landing page is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional technical detail. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The endpoint's actual response format must be inferred or discovered by making a paid request.
Capabilities
Use cases
- —Fetching the current USD to SGD exchange rate for financial applications
- —Programmatic forex data retrieval without API key management
- —Agent-driven currency conversion workflows that settle micropayments on Base
- —Embedding live FX rates into trading bots or dashboards
Fit
Best for
- —Developers needing simple pay-per-call forex data without subscriptions
- —AI agents that can settle x402 payments on Base
- —Low-volume or sporadic forex rate lookups at $0.02 each
Not for
- —High-frequency trading requiring sub-second latency and bulk pricing
- —Users who need historical forex time-series data (no evidence this is supported)
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/forex/USDSGD \
-H "X-PAYMENT: <x402_payment_token>" \
-H "Content-Type: application/json"Endpoint
Quality
The x402 challenge is live and confirms pricing and network, but there is zero documentation on request parameters, response schema, or usage examples. Docs pages are empty beyond a wallet-connect prompt. The listing is effectively a stub with only the challenge metadata and landing page to go on.
Warnings
- —No OpenAPI spec or request/response schema available
- —All documentation pages (docs, API, pricing, README) render only 'Connect wallet' with no content
- —Response format for the forex endpoint is entirely undocumented and must be discovered empirically
- —The broader lowpaymentfee.com platform lists many endpoints but provides no technical documentation for any of them
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/forex/USDSGD
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/forex/USDSGD
- —All APIs priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The site lists forex under Finance & Web3 category alongside price feeds, exchange rates, token quotes, and gas estimateshttps://lowpaymentfee.com