Why Is My App Slow? How to Make It Faster Without a Developer
You built your app with Claude, ChatGPT, Bolt, or Lovable and it works, but it is slow. Pages take a few seconds to load. Actions feel sluggish. Users are…
You built your app with Claude, ChatGPT, Bolt, or Lovable and it works, but it is slow. Pages take a few seconds to load. Actions feel sluggish. Users are complaining or dropping off before things finish loading. You are not sure if the problem is your code, your hosting, your database, or something else entirely. Slow apps are one of the most common problems for vibe coders after getting something live, and diagnosing them is more straightforward than most people think.
Here is a practical guide to finding what is slow and fixing it.
Why Apps Get Slow: The Four Main Causes
Before fixing slowness, you need to know which of these four things is causing it. They have different fixes.
Slow database queries. If your app reads from a database, a poorly structured query can take seconds to return results. This is especially common as your data grows. A query that was fast with ten records can crawl with ten thousand.
Large images and files. Uncompressed images are one of the most common causes of slow web app load times. A single high-resolution image that has not been optimised can be larger than the entire rest of your app.
Too many requests on page load. If your app makes ten API calls every time a page loads, the page cannot finish rendering until all ten complete. Each API call adds latency.
Under-resourced hosting. Free hosting tiers have limited memory and CPU. As your app grows or gets more traffic, it may simply be running on a server that does not have enough resources to respond quickly.
How to Find What Is Actually Slow
Use your browser’s developer tools. On Chrome or Firefox, open your app, right-click and select Inspect, then click the Network tab. Reload the page. You will see every request your app makes, how long each one took, and how large each file is. Look for anything that takes more than a second or files larger than a few hundred kilobytes.
Check your database query times. Supabase and Firebase both have dashboards that show query performance. If a query is slow, it will appear there. Ask your AI: “How do I see slow database queries in my [Supabase/Firebase] dashboard?”
Check your hosting platform’s metrics. Vercel, Railway, and Render all show memory and CPU usage. If either is consistently near 100 percent, you need more resources.
The Fastest Fixes for Each Cause
Slow database queries: ask your AI: “This is my database query: [paste it]. Can you optimise it and add an index on the fields I am querying most often?” Indexes dramatically speed up queries on large datasets.
Large images: compress them before uploading. Use a free tool like Squoosh.app to reduce image file sizes by 70-90 percent with no visible quality loss. Or ask your AI to add image optimisation to your app.
Too many API calls on load: ask your AI: “My app makes multiple API calls when the page loads. Can you refactor it to combine requests or load non-critical data after the page is visible?” This is called lazy loading.
Under-resourced hosting: upgrade to a paid tier on your current platform, or move to a platform with better free tier performance. Vercel generally has better performance on free tiers than Render or Railway for web apps.
How to Measure Improvement
Before and after making changes, measure your app’s load time using PageSpeed Insights at pagespeed.web.dev. Paste your app’s URL and it will give you a score and specific recommendations. This is a free Google tool that takes thirty seconds to use and gives you concrete data rather than guesswork.
The One Thing to Remember
Slow apps are almost always caused by one of four things: slow database queries, large images, too many API calls on load, or under-resourced hosting. Use your browser’s Network tab and PageSpeed Insights to find the bottleneck, then ask your AI to fix the specific problem. Most performance issues have straightforward fixes that do not require a developer.
Want your app running fast and reliably in the cloud? → Snapdock
New here? These might help: What is a database? And does my app actually need one? → What is caching? Why your app sometimes shows old information. →