> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bult.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Compute Sizes

Bult offers flexible compute sizes to match your app’s needs, billed per minute.

Free tier includes XS, S, and M.

Pro plan (September 2026) unlocks L to 3XL.

Configure in Canvas UI’s “**General**” tab in "**Edit Service**":

<img src="https://mintcdn.com/bultapp/oARalHyp_EVl_9Ix/images/Screenshot2025-08-07at19.46.36.png?fit=max&auto=format&n=oARalHyp_EVl_9Ix&q=85&s=53093449ac26e8e4b2794a15fcac3aa1" alt="Screenshot 2025-08-07 at 19.46.36.png" width="868" height="742" data-path="images/Screenshot2025-08-07at19.46.36.png" />

| Size | vCPU | RAM    | Price (Monthly) | Tier      | Use Case              |
| :--- | :--- | :----- | :-------------- | :-------- | :-------------------- |
| XS   | 0.1  | 256 MB | \$2.7           | Basic/Pro | Prototypes            |
| S    | 0.25 | 512 MB | \$5.4           | Basic/Pro | Small Apps            |
| M    | 0.5  | 1 GB   | \$12            | Basic/Pro | Web Apps              |
| L    | 1    | 2 GB   | \$24            | Pro       | APIs                  |
| XL   | 2    | 4 GB   | \$48            | Pro       | Databases             |
| 2XL  | 4    | 8 GB   | \$96            | Pro       | High-traffic          |
| 3XL  | 8    | 16 GB  | \$192           | Pro       | Enterprise-scale apps |

View Compute Sizes minutely, hourly, and monthly: [https://bult.ai/#pricing](https://bult.ai/#pricing).

**Details**:

* **Instances**: Free tier supports 1-2 instances per service; Pro allows up to 10.
* **Scaling**: Auto-scaling available with Pro plan. Manual scaling in Canvas UI.
* **Usage**: Monitor CPU/RAM in app.bult.ai/usage. Example: XS at 21.12 hours costs \$0.03 (CPU) + \$0.04 (RAM).
* **Limits**: Free tier caps at 0.5 vCPU, 1GB RAM total. Pro supports up to 8 vCPU, 16GB RAM.
* **Optimization**: Start with XS for prototypes. Upgrade to M/L for production to avoid “Out of capacity” errors.

**Example**: Deploy an Express.js app with XS compute:

1. Select “**GitHub Repository**” in Canvas UI.
2. Set compute to XS (0.1 vCPU, 0.25 GB RAM).
3. Deploy and monitor costs in [app.bult.ai/usage](https://app.bult.ai/usage).