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

[Ranjit-Khanal]

Bug Report: Node.js Heap Out of Memory on NestJS Startup

Issue Summary

Running yarn start or yarn dev in the @calcom/api-v2 monorepo causes Node.js to crash with a “JavaScript heap out of memory” error. This occurs because the NestJS app loads multiple workspaces and libraries simultaneously, which exceeds the default Node memory limit (~2 GB).

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Steps to Reproduce

1. Clone the repository and run yarn install to install dependencies.
2. Run yarn start or yarn dev:no-docker.
3. Wait for the NestJS application to start building all workspaces.

Additional Context:

• The repo is a monorepo with multiple workspaces (@calcom/platform-libraries, @calcom/platform-utils, etc.) and a TRPC server.
• Even on a machine with 16 GB RAM, Node’s default heap crashes during startup.

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Actual Results

• Node.js throws the following error:

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

• The application does not start.

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Expected Results

• The application should start successfully without crashing, allowing development and API testing to proceed.

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Technical Details

• Node.js version: v24.13.0 (via nvm)
• Yarn version: 1.22.x or 3.x (workspace-enabled)
• Operating System: Linux (Ubuntu) / macOS
• Screen recording / console logs show memory allocation failures during NestJS startup.
• Multiple large TypeScript projects and watch processes are running simultaneously.

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Evidence

• Tested by running yarn start on a machine with 16 GB RAM.
• Error appears consistently within 30–60 seconds of startup.
• Observed GC logs in console:

[linear]

CAL-7278

[Ranjit-Khanal]

the fix is on pull request
#28234

[romitg2]

Development tip
Add export NODE_OPTIONS=“--max-old-space-size=16384” to your shell script to increase the memory limit for the node process. Alternatively, you can run this in your terminal before running the app. Replace 16384 with the amount of RAM you want to allocate to the node process.

we've covered the solution readme! can you please try