Please try the latest jsreport so we can isolate if it's a problem with the older Chrome binary or not.

It works in the playground, right?
If this is the case, try installing the same fonts as those in the playground on your server.
https://github.com/jsreport/playground-worker/blob/master/Dockerfile#L9
If you use the same, I am afraid the problem can be with the old Chrome in the jsreport 2.10.0 and you may need to update.

What kind of container do you deploy there? An official jsreport image? Or something custom? Can you try the default and full jsreport images?

Note we have a dedicated tutorial for using serverless google cloud functions here
https://jsreport.net/learn/gcloud-functions-serverless

I'm afraid you'll have better luck at a LibreOffice forum as this is directly related to it...

But maybe someone else has a solution to improve LibreOffice perf when converting on Windows and poor HW specs?

I've tried it and it works fine for me. The container gets created and after import from the studio, the blobs are created there.

Could you try to isolate the problem and elaborate?

Hi,

please try to isolate the problem. The 15MB JSON shouldn't be the problem so we need to find out where the things hang.

Could you share the jsreport output logs?
Could you try to render the report with a client tool like postman or curl so we avoid client issues?

We have some notes about long tables here
https://jsreport.net/learn/chrome-pdf#troubleshooting

If that doesn't help, could you share a minimal playground demo?
https://playground.jsreport.net/

Yes, the second report execution will queue. That is what I am observing, see the logs.

2025-04-07T05:11:14.181Z - info: 1 worker threads initialized in 111ms
2025-04-07T05:11:14.181Z - info: Starting temp files cleanup with 180000ms threshold
2025-04-07T05:11:14.182Z - info: reporter initialized
2025-04-07T05:11:17.375Z - info: Responding with async report location and continue with async report generation rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:17.377Z - info: Async report is starting to render 23d579ac-2fd0-4f25-8607-42ed1a5f05f5
2025-04-07T05:11:17.380Z - info: Render request 2 queued for execution and waiting for available worker rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:17.525Z - info: Starting rendering request 2 rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:17.525Z - info: Rendering template { name: test, recipe: chrome-pdf, engine: handlebars, preview: false } rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:17.525Z - debug: Data item not defined for this template. rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:17.529Z - debug: Base url not specified, skipping its injection. rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:17.529Z - debug: Rendering engine handlebars rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:17.949Z - info: Responding with async report location and continue with async report generation rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:17.950Z - info: Async report is starting to render 3630ab9c-6d78-419b-a9cf-2a659b2964d4
2025-04-07T05:11:17.953Z - info: Render request 4 queued for execution and waiting for available worker rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:22.829Z - debug: Executing recipe chrome-pdf rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:23.111Z - debug: Converting with chrome Chrome/133.0.6943.126 using dedicated-process strategy rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:23.142Z - debug: Page request: GET (document) file:///C:/Users/janbl/AppData/Local/Temp/jsreport/autocleanup/f833d045-a92b-4559-a439-8f47388cb2b9-chrome-pdf.html rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:23.150Z - debug: Page request finished: GET (document) 200 file:///C:/Users/janbl/AppData/Local/Temp/jsreport/autocleanup/f833d045-a92b-4559-a439-8f47388cb2b9-chrome-pdf.html rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:23.152Z - debug: Running chrome with params {"printBackground":true,"timeout":44416,"margin":{}} rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio  
2025-04-07T05:11:23.291Z - debug: Report stored as reports/test/23d579ac-2fd0-4f25-8607-42ed1a5f05f5.pdf rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:23.291Z - info: Rendering request 2 finished in 5914 ms rootId=nl1z7tegzitxpio, id=nl1z7tegzitxpio
2025-04-07T05:11:23.292Z - info: Async report render finished 23d579ac-2fd0-4f25-8607-42ed1a5f05f5
2025-04-07T05:11:23.294Z - info: Starting rendering request 4 rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:23.294Z - info: Rendering template { name: test, recipe: chrome-pdf, engine: handlebars, preview: false } rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:23.294Z - debug: Data item not defined for this template. rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:23.296Z - debug: Base url not specified, skipping its injection. rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:23.296Z - debug: Rendering engine handlebars rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:28.307Z - debug: Executing recipe chrome-pdf rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:28.477Z - debug: Converting with chrome Chrome/133.0.6943.126 using dedicated-process strategy rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:28.505Z - debug: Page request: GET (document) file:///C:/Users/janbl/AppData/Local/Temp/jsreport/autocleanup/330a112c-dcd5-4ad6-932b-3edad5b73362-chrome-pdf.html rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:28.516Z - debug: Page request finished: GET (document) 200 file:///C:/Users/janbl/AppData/Local/Temp/jsreport/autocleanup/330a112c-dcd5-4ad6-932b-3edad5b73362-chrome-pdf.html rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:28.516Z - debug: Running chrome with params {"printBackground":true,"timeout":39640,"margin":{}} rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2  
2025-04-07T05:11:28.652Z - debug: Report stored as reports/test/3630ab9c-6d78-419b-a9cf-2a659b2964d4.pdf rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:28.652Z - info: Rendering request 4 finished in 10702 ms rootId=non6rfa6ar7ajz2, id=non6rfa6ar7ajz2
2025-04-07T05:11:28.653Z - info: Async report render finished 3630ab9c-6d78-419b-a9cf-2a659b2964d4

But that is expected that with this header you get back the response immediately. The idea is that it doesn't need to wait for available worker to parse the request. Or what am I missing?

Hi, it seems to work for me fine...

Are you on the latest 4.8.0? There was a fix included for the jsreport-Options-Reports-Async.
Is there anything specific you do? Authentication enabled, some extra configs... ?