Cyrillic Transliterator: Latin To Cyrillic
A Latin-to-Cyrillic and Cyrillic-to-Latin converter. It supports Serbian Azbuka, Russian, and other Slavic alphabets using established international standards.
Online version: cyrillic.app - Free Online Latin-To-Cyrillic Converter
More features are available in the iOS, macOS and Android versions.
Supported alphabets: Serbian; Serbian, Belarusian, Bulgarian, Macedonian, Montenegrin, Russian and Ukrainian (ISO 9:1995).
Success
With around 50,000 downloads, the Android version is one of the most successful apps of its kind!