> For the documentation index, fetch https://sync.so/docs/llms.txt. Append .md to a page URL for Markdown. Documentation-search MCP: https://sync.so/docs/_mcp/server.

# API Guides

## Docs

- [Authentication](https://sync.so/docs/api-reference/guides/authentication.md): Learn how to authenticate with the sync. labs lip sync API using API keys. Setup guide, security best practices, and code examples.
- [Idempotent generation requests](https://sync.so/docs/api-reference/guides/idempotency.md): Retry generation requests without duplicating work. Learn how to send Idempotency-Key, handle replay responses, and recover from timeouts.
- [Concurrency & Rate Limiting](https://sync.so/docs/api-reference/guides/rate-limits.md): Understanding sync. labs API rate limits, concurrency limits, and retry strategies for lip sync generation.
- [Batch Processing](https://sync.so/docs/api-reference/guides/batch-processing.md): Batch processing API for bulk AI lip sync generation. Process up to 500 videos in a single operation with webhooks and status tracking.
- [Webhooks](https://sync.so/docs/api-reference/guides/webhooks.md): Set up webhooks for real-time lip sync generation status updates. Includes signature verification, error handling, and code examples.