How to cache exchange rates in Node.js?

Use a Map with TTL checks, as shown. Add stale-while-revalidate for zero perceived latency.

What's the best TTL for exchange rate caching?

1-5 min for displays, 30s for payments, 24h for billing. Match your use case—don't overfetch.

Minimal—rates move slow. Stale serving + background refresh keeps you under 10-min drift, plenty accurate for 99% apps.

Deployed your app, watched rate limits crush it. Caching exchange rates fixes that—forever. Here's the architecture that scales.

theAIcatchup Apr 10, 2026 4 min read

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#API caching #api rate limits #cache exchange rates #exchange rate caching #exchange rates api #production optimization #rate limit errors #rate limiting #redis-caching #stale-while-revalidate

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Originally reported by dev.to