> For the complete documentation index, see [llms.txt](https://docs.nftrainbow.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nftrainbow.xyz/about-the-apis.md).

# ABOUT THE APIs

- [Authentication](https://docs.nftrainbow.xyz/about-the-apis/authentication.md)
- [Error codes](https://docs.nftrainbow.xyz/about-the-apis/error-codes.md)
- [Quotas and rate limits](https://docs.nftrainbow.xyz/about-the-apis/quotas-and-rate-limits.md)