Nuxt 4 server memory leaking?
I have just started the process of deploying my Nuxt 4 server onto an existing group of 6 servers. I have basically zero traffic (other than Cloudflare health checks) as I have production still using Cloudflare Pages, but I was looking at memory usage and all 6 servers are slowly growing in memory and then eventually crashing. What's the best path to troubleshooting this? I worry its going to be start removing modules until it doesn't do this anymore.
11 Replies
Hi @Brett. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:
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Based on the knowledge sources, there are several documented memory leak issues in Nuxt 4 that could be causing your problem:
Known Memory Leak Issues in Nuxt 4
1. Memory leak in Nuxt 4.2.0 with
useFetch/useAsyncData
There's a confirmed memory leak in Nuxt 4.2.0 related to useFetch and useAsyncData. The issue was traced to an EventListener in useAsyncData that doesn't get removed if the abort event is never triggered. This was also backported to affect Nuxt 3.20.0+.
2. EffectScope memory leak with await in Vue setup blocks
Another documented issue in Nuxt 4 occurs when Vue component setup blocks have await calls in them. The EffectScope stays alive and leaks even after the request has ended. This issue did not exist in Nuxt 3.
Troubleshooting Steps
Based on the knowledge sources, here are recommended approaches:
1. Check your Nuxt version: If you're on 4.2.0, consider downgrading to 4.1.3, which doesn't have the memory leak issue regardless of Vue version.
2. Review await usage in components: If you have await calls in Vue component setup blocks, try using callOnce instead of useAsyncData for initialization tasks, as this resolved the issue for one user.
3. Check for common memory leak patterns: According to a Stack Overflow discussion, common causes include:
- Wrongly using plugins on the server-side
- Creating intervals that aren't cleaned up
- Other patterns that prevent garbage collection
4. Monitor with Node inspector: Use Node's built-in inspector to profile memory usage and identify what's accumulating, as demonstrated in the memory leak investigation.
Unfortunately, the knowledge sources suggest that systematically removing modules may indeed be necessary if the above steps don't resolve the issue, as memory leaks can be caused by specific module interactions.
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----------------------<@207104288789364736> Kapa.ai is still learning and improving, please let me know how I did by reacting below.
@Brett depends how deep you wanna go:
* You could make memory snapshots of prod and look into them, which is the most granular but also most clear way to debug what is going on
* Take a look at refs outside of plugins and components which might accidentally leak into global context. Use
useState instead.
* Anything outside of middleware or plugins actuallyAlexander Lichter
YouTube
Why you should use useState()
VUEJS AMSTERDAM DISCOUNT (20%): i-really-like-alexander-lichter
🔛 Sending state from the server to the client is tricky but necessary when using SSR. And global state management is not the easiest part of an app either. Nuxt's useState composable solves both of these issues - but how? You'll learn in this weeks video!
Key points:
⏩️ Ho...
I think it might be the Nuxt 4.2 and Vue upstream bug
I had to go through this process once. Ended up using divide and conquer removing code and found the issue in a couple of hours.
Generated a sitemap and hit it with 1000s request in parallel. Did this with a production build running locally and logging the memory consumption.
could also be!
You can try the vue 3.6 alpha for that if you want
is this during the build stage? we’ve got sorta the same issue but i think that was more just npm memory usage n stuff
@kapa.ai how do you downgrade to 4.1.3
Let me check the knowledge base for you again. One moment! :books:
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To downgrade to Nuxt 4.1.3, you need to update your
package.json and reinstall dependencies. While the knowledge sources don't provide explicit step-by-step instructions for downgrading, they do reference users successfully downgrading to this version.
Based on the information available, here's how to downgrade:
1. Update your package.json:
2. Reinstall dependencies:
- If using npm: npm install
- If using pnpm: pnpm install
- If using bun: bun install
3. Clear your build cache (recommended):
- Delete the .nuxt directory
- Delete node_modules/.cache if it exists
4. Restart your dev server or rebuild for production
Multiple users in the knowledge sources confirmed that downgrading to Nuxt 4.1.3 resolved their issues, with one user specifically noting that "Nuxt 4.1.3 and vue 3.5.22" worked without memory leaks.
Note: After downgrading, you may want to verify your installation by checking the version output when starting your dev server, which should show something like Nuxt 4.1.3 (with Nitro X.X.X, Vite/Rolldown-Vite X.X.X and Vue X.X.X).
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Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:
----------------------<@332238302457495564> Kapa.ai is still learning and improving, please let me know how I did by reacting below.
Nuxt 4.2.1 seemly has resolved this issue (from 4.2.0)