> For the complete documentation index, see [llms.txt](https://docs.facephi.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.facephi.com/docs.facephi-en/sdks/backend-sdk/selphid.md).

# SelphID SDK

**FacePhi SelphID SDK** is a backend facial biometrics solution written in modern C++ that allows, among other things, facial comparison, passive liveness check evaluation, and gallery search (1:N). Expanding on each of these functionalities:

* **Facial matching**: you can perform facial comparisons with multiple options tailored to your needs. The most important ones:
  * *Image* with a *image*.
  * *Biometric template* with a *biometric template*.
  * *Biometric raw template* with a *biometric raw template*.
  * *Image* with a *biometric template*.
  * *Image* with a *biometric raw template*.
  * *Image* with a *raw document image*.
  * *Biometric raw template* with a *raw document image*.
* **Passive liveness**: you can evaluate whether a photograph or *biometric template* facial is fraudulent.
* **Gallery search**: you can create and manage galleries with multiple *biometric templates* and use them for 1:N authentication with *images* or *biometric templates*.

Recommended image format:

* JPG
* PNG

All *biometric template* and *raw template* en **SelphID SDK** is encrypted for greater security.