freelancer for firebase firestore apps hire react developer freelancer for app refactoring and cleanup fullstack dev mern stack developer web programming website design dotnet developer freelancer for headless ecommerce sites freelancer for biometric time tracking nextjs app development freelancer for langchain agent apps freelancer for whisper api transcription react https://software-developers-15-1246789.ttblogs.com/16088746/the-best-side-of-software-developer-kpi-template