Fly.io provides basic infrastructure metrics and logs, but can't explain why an app is slow or which endpoint is causing issues. AppSignal fills this gap by auto-instrumenting Node.js apps (Express, Fastify, Koa, Next.js) to capture per-route response times, grouped errors, database queries, host metrics, and logs in one
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What Fly.io Gives You (and What It Doesn’t)What AppSignal Captures in Your Node.js AppThe Signals AppSignal Surfaces on Fly.ioFly-Specific Things to WatchConnecting Deploys to ChangesAlerts Worth SettingWrapping it UpSort: