# How to use OpenCV in Blazor

**URL:** <https://forum.opencv.org/t/how-to-use-opencv-in-blazor/13115>\
**Category:** Uncategorized\
**Tags:** opencvjs\
**Created:** [May 9, 2023, 4:02pm UTC](https://forum.opencv.org/t/how-to-use-opencv-in-blazor/13115 "2023-05-09T16:02:42Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![caro](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@caro](https://forum.opencv.org/u/caro)\
**Post date:** [May 9, 2023, 4:02pm UTC](https://forum.opencv.org/t/how-to-use-opencv-in-blazor/13115/1 "2023-05-09T16:02:42Z")

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How do I OpenCV in Blazor (WebAssembly)? I have tried OpenCV.js and OpenCV4Sharp. I am trying to do Detect face using DetectMultiScale but it genates a error that doesn’t tell me what the problem is. Can I use any implementation of OpenCV whether it is OpenCV.js, OpenCV4Sharp or EmguCV within a Blazor WebAssemly app when I need to detect a face?

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**Author:** ![crackwitz](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/crackwitz/32/14_2.png) [@crackwitz](https://forum.opencv.org/u/crackwitz)\
**Post date:** [May 10, 2023, 10:33am UTC](https://forum.opencv.org/t/how-to-use-opencv-in-blazor/13115/2 "2023-05-10T10:33:24Z")

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you’d best ask that people who know what Blazor is and how it works.

OpenCV is a C++ library. It has bindings for Python, which means that the compiled C++ code is called.

The OpenCV.js subproject uses **emscripten** to compile _selected_ (tested) parts of OpenCV such that they can run in a browser.

there is no official support for C#. all those efforts are third-party bindings, i.e. compiled C++ code is called.