# What is Cold Start?

The delay when a serverless function starts up after being idle. It affects the first request after a quiet period but not subsequent ones.

## In real work

This webhook has a cold start problem. Move heavy initialization outside the handler to shorten startup time.

## Related terms

- [Preview Deployment](https://prompthausapp.com/learn/preview-deployment.md)
- [ISR](https://prompthausapp.com/learn/isr.md)
- [Edge Network](https://prompthausapp.com/learn/edge-network.md)
- [Fluid Compute](https://prompthausapp.com/learn/fluid-compute.md)
- [Rollback](https://prompthausapp.com/learn/rollback.md)

## How is this different from Googling it?

Google gives a definition. Prompthaus pairs each term with how it shows up in standups, PRs, prompts, and design reviews—then quizzes you until the word sticks. One term a day on iPhone.

- Category: Launch
- HTML: https://prompthausapp.com/learn/cold-start
- App Store: https://apps.apple.com/us/app/prompthaus-ai-vocabulary/id6776314407