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

# FAQ

> BizyAir FAQ: API Key, calling modes, billing, refunds, output file validity, and concurrency limits.

## Account and API Key

**Q: How do I get an API Key?**

Log in to bizyair.ai, go to User Center, open API Keys, click "Create New Key", and copy the 48-character key (shown only once).

**Q: What if my API Key is leaked?**

Immediately disable the old key in User Center and create a new one. Never commit keys to Git, write in frontend code, or share publicly.

## Calling Modes

**Q: What's the difference between sync, async, and WebHook?**

| Mode        | Use Case                      | Description                   |
| ----------- | ----------------------------- | ----------------------------- |
| Synchronous | Short tasks (\< 60s)          | Connection stays open         |
| Async       | Long tasks, unstable networks | Returns requestId for polling |
| WebHook     | Production, high concurrency  | POST callback on completion   |

**Q: What if synchronous call times out?**

Ensure HTTP client read timeout is at least 60 seconds. If timed out, the task may still complete in the cloud — query status with requestId via /detail.

## Billing

**Q: Is there a charge for canceled tasks?**

Queuing and Preparing cancellations are free. Running interrupts are billed for elapsed time. Platform-caused interruptions are free.

**Q: What happens when balance is insufficient?**

Returns `{"code": 42901, "message": "insufficient credits"}`. Please top up first.

## Output Files

**Q: How long are result files valid?**

Output files (object\_url) are valid for 15 days and cannot be recovered after expiry. Download to your own storage immediately.

## Concurrency

**Q: How do I increase concurrency?**

Upgrade your tier (User Center → Plans) or contact business at [contact@bizyair.ai](mailto:contact@bizyair.ai).

**Q: What should I do with 429 errors?**

Reduce concurrency, use exponential backoff retry, or upgrade your tier.

## ComfyUI

**Q: What if a node is missing?**

Visit the [BizyAir Discord community](https://discord.gg/bizyair) and submit a request in the `#feature-request` channel.