Serverless Cold Start Comparison
Find the perfect solution for your specific platform and free tier constraints.
What are cold starts and why do they matter?
Cold starts occur when a serverless platform needs to allocate resources for an inactive application. This creates a significant delay (from hundreds of milliseconds to 30+ seconds) for the first request after a period of inactivity.
For your users, this means:
- Frustrating load times on first access
- High bounce rates as users lose patience
- Failed API calls when timeouts are exceeded
- Poor user experience especially for interactive apps
Platform Comparison
| Platform | Sleep Policy | Cold Start Time | Keep Alive Effectiveness | Recommended Ping Interval |
|---|---|---|---|---|
| AWS Lambda | Function recycled after ~15-60 min inactivity (varies) | 100ms - 10s (depends on runtime/VPC) | 5-10 minutes | |
| Render | Free tier: 15 min inactivity then sleep | 20-40 seconds to wake up | 10-12 minutes | |
| Amplify Functions | Same as AWS Lambda | 100ms - 5s (typically) | 5 minutes | |
| Heroku | Free tier: 30 min inactivity + 6hr/day forced sleep | 10-30 seconds to wake up | 25 minutes | |
| Vercel | Serverless functions recycled after inactivity | 100ms - 3s (typically) | 5 minutes |
* Heroku's 6-hour mandatory sleep per 24 hours cannot be circumvented with pinging
How does Keep Alive solve these issues?
Keep Alive sends periodic HTTP requests to your endpoints before they go to sleep, ensuring they stay warm and responsive. Unlike complex DIY solutions, Keep Alive:
- Works across all major serverless platforms
- Requires zero code changes to your application
- Provides customizable ping intervals per endpoint
- Shows real-time status monitoring
- Handles all retry logic and error handling
Choosing the Right Platform
When deciding between serverless platforms, consider these factors:
- Application needs: API-driven backends do well on Lambda/Vercel, full-stack apps on Render/Heroku
- Cold start tolerance: User-facing apps need consistent response times
- Budget constraints: All platforms have free tiers with different limitations
- Development workflow: Amplify/Vercel integrate well with frontend workflows
Keep Alive works with all these platforms, giving you flexibility to choose based on your needs rather than cold start concerns.