Every await in Your Node.js API Is a Pause. Chain 3 of Them and You've Built a 750ms Endpoint. Sequential async/await is the most common performance mistake in Node.js backends. It feels right clean, readable, easy to reason about. It's also serialising database calls that have zero dependency on each other. When you await getUserData, then await getOrders, then await getNotifications, you're processing one at a time. Node.js sits idle between each call waiting for the previous to resolve. You've turned an async runtime into a synchronous one. Promise.all changes everything. Wrap independent calls in Promise.all and they fire simultaneously. Your 750ms endpoint becomes 300ms the time of the slowest single query, not the sum of all of them. This isn't micro-optimisation. On endpoints that serve every page load, this is the difference between a snappy product and one that feels slow. Layer Redis in front and repeat requests return in 5ms. Cache invalidation is a single key delete. Most dashboard data doesn't change every second — stop pretending it does. Real impact: 750ms sequential response becomes 90ms parallel. Cached responses serve in 5ms. Your database handles a fraction of the load because repeated reads never reach it. Promise.all is one of the highest-leverage changes you can make to a Node.js API. If you're not using it for independent async calls, you're leaving performance on the table every single request. #NodeJS #BackendDevelopment #JavaScript #WebPerformance #API #Redis #Caching #SoftwareEngineering #Programming #WebDevelopment #Backend #TechTips
Very great post. Keep it up.
Muhammad Shuja Mustafa Thanks for these useful insights!
Sometimes we always want to show a concurrency patten that will increase our apps but forget error handling. In this case if one of the db calls fails, all other calls return nothing without actually knowing what happens. yes Promise.allSettled solves this but also we need to handle error on each step of the way. Something I had to learn by force while learning Golang
in the given example parallel one should still be 300ms. isn’t it? Why is it 90?
Very insightful post