USD/SGD forex exchange rate via x402 micropayment on Base network
What it does
This endpoint provides the current USD/SGD foreign exchange rate, accessible via the x402 payment protocol on the Base network. It is part of a broader suite of APIs offered by lowpaymentfee.com, which spans data analytics, AI/ML inference, finance, crypto, and utility services — all gated behind per-request x402 micropayments.
The endpoint accepts POST requests and returns JSON. Each call costs $0.02 in USDC (USD Coin) on the Base L2 network (asset contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913). The maxAmountRequired in the x402 challenge is 20000 base units; since USDC uses 6 decimals, this equals $0.02. No API keys or rate limits are advertised — access is granted purely through the x402 payment header. The payment timeout is 300 seconds.
Documentation beyond the landing page is extremely sparse. The /docs, /pricing, /api, and /README pages all returned only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no example request/response payloads, and no description of what fields the forex rate response contains. The endpoint is confirmed live (returns 402 challenge as expected), but the lack of documentation means callers must discover the response format empirically.
Capabilities
Use cases
- —Fetching the current USD/SGD exchange rate for financial applications
- —Automated currency conversion in trading bots or payment systems
- —Embedding real-time forex data into dashboards or reports
- —Agent-driven forex lookups without API key management
Fit
Best for
- —Developers needing on-demand USD/SGD rates without subscription commitments
- —AI agents that can pay per-request via x402 on Base
- —Applications requiring keyless, low-friction forex data access
Not for
- —High-frequency trading requiring sub-second latency guarantees (no SLA documented)
- —Users needing historical forex time-series data (only current rate advertised)
- —Consumers without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/forex/USDSGD/rate \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_header>"Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no documented request/response format, no example payloads, and all documentation pages are empty stubs. The listing is effectively a stub with only the x402 challenge and landing page to work from.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README all return only a wallet-connect prompt with no content
- —No OpenAPI or JSON schema describing request parameters or response fields
- —Response format for the forex rate endpoint is completely undocumented and must be discovered empirically
- —No SLA, uptime guarantees, or data source attribution documented
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/forex/USDSGD/rate
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/forex/USDSGD/rate
- —All APIs on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The site lists finance, AI/ML, data analytics, crypto, and utility API categorieshttps://lowpaymentfee.com