---
title: JavaScript heap out of memory error in self-hosted Langfuse
description: "Why self-hosted Langfuse containers hit JavaScript heap out of memory errors, and how to raise the Node.js heap limit to match the memory you allocated."
tags: [self-hosting]
---

# JavaScript heap out of memory error in self-hosted Langfuse

If you are experiencing JavaScript heap out of memory errors within your applications, it indicates that the application thinks it has less memory available than it does.
An example case is that your container has 2 GiB of memory, whereas the Node.js application uses the default max-old-space-size of 1.7 GiB.
This would surface as an error message like

> FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory

To address this issue, we recommend that you configure `NODE_OPTIONS=--max-old-space-size=${var.memory}` on the Langfuse Web and the Langfuse Worker containers.
Use the available memory in MiB as the value for `var.memory`, e.g. 4096 for 4 GiB of memory.
The value should be equal or above the memory limit of the container.
This ensures that your container orchestrator kills the pod gracefully if the memory limit is exceeded, instead of the application terminating abruptly.

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