Unbelievably slow UI

Describe the problem/error/question

When using the n8n UI, after 5-10 minutes, typing in any text field becomes unbearably slow. This has been happening for a while, but it’s gotten to a point of productivity-blocking that I have to say something.

What is the error message (if any)?

No error messages, just a significant (3-6 second) delay between text input and response.

In the Chrome browser console, however, I do see log entries basically at each keystroke:

Nothing of note in the logs, CPU usage of the instance is 5-6%, 1.5 GB of memory free, etc.

Please share your workflow


2023-10-25 16.25.43

Information on your n8n setup

  • n8n version: 1.11.1
  • Database: SQLite
  • n8n EXECUTIONS_PROCESS setting (default: own, main):
  • Running n8n via (Docker, npm, n8n cloud, desktop app): Docker
  • Operating system: Linux

I am tearing my hair out trying to get a pretty simple workflow done, any and all ideas and help welcome!

I’m unfortunately not able to reproduce this on 1.11.1.
Can you please try this in another browser, to rule out that this is not being caused by some browser plugin?
If you still see those logs in the console, can you please share the right side of the console as well, that says which file the logs are coming from :pray: ?

Hi @netroy, thank you so much for the quick response.

I just tried in Safari, same issue, and I disabled all extensions/plugins on Safari when testing.

2023-10-25 18.12.41

I don’t get the messages in the console in Safari, but the typing speed is still very laggy… and again, it seems to get worse with time (i.e. seems like a memory leak).

In Chrome, the tab that has been open and is super laggy, I do see a 1.3 GB memory footprint in the task manager.

Regarding your request for the ‘right side of the console’, I’m sorry :grimacing: but I can’t quite figure out what you mean. When there is an error or a warning, I do see the filepath, but not when it’s a simple .log().

Lastly, I opened the new “Performance Monitor” in Chrome, and I see huge CPU usage when typing, or really, when doing anything in the UI (opening a node takes 12 seconds during which the CPU is pegged at 100%).

Thanks a lot for that detailed reply.
Does this happen after you have some manual execution data in some previous nodes? or does this happen right after opening the workflow without any execution data?

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It’s still slightly slow and laggy when opening in a fresh tab, and it gets progressively worse as I start to work through the workflow. I’m currently trying to make one of the final nodes work, and so I am running the previous ones via manual executions to have the data needed for the final node.

Even after running all nodes, it’s still not “ultimate lag” status- that comes when I’ve been working on things for a while.

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Maybe a clue?

On a whim, I decided to check how many JS event listeners were registered… there’s over 75k+!!!
Screen Shot 2023-10-27 at 15.24.47

Reddit.com has 4,000, and it’s one of the worst performing websites I know. N8n.io has 1,105, github.com has 8,600.

This behavior definitely ‘feels’ like JS thread blocking to me. Is there something (a node, a config, etc.) that could be creating duplicate or erroneous JS event listeners.


  1. If I navigate to another workflow, and wait, something like GC kicks in and it goes back down to 4-7k.
  2. Navigating back to the original workflow, the event listeners stay low, and the UI is slow but responsive.
  3. As I continue using the workflow, I’m seeing the number of event listeners climb by 2-3k each time I open a node, and doesn’t go back down when closing it. As I’m doing this, the UI is getting laggier and laggier.
  4. Refreshing the page drops the JS heap size and event listeners down HUGELY.

Edit: I can confirm that the lag on the UI is directly proportional to the # of event listeners.

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Gentle bump to see if anyone has an idea if:

  1. That # of event listeners is normal
  2. If not, why they’re not being managed properly
  3. What could be done about it :slight_smile:

I’ve struggled with performance in the past but haven’t really seen it for a long time.

Have you tried re-creating the entire workflow - node for node - in a new flow. Just copy one node at a time? I still see mysterious bugs now and then that can only be solved by starting from a fresh.

Hey @systemaddict I know exactly what you’re talking about, I’ve had to do the same myself. It seemed relayed to ‘ghost’ parameters that were dangling after deleting a field that previously held a value… but yes, I know what you’re talking about.

If I’m really the only one experiencing this, I’ll give it a shot…

Same here in Version 1.16.0