SP

Open to opportunities

Sergei Piskov

@sergeipiskov

I build secure, scalable Android fintech apps for millions of users.

What I'm looking for

I'm looking to build secure, scalable Android fintech and high-load consumer applications, improving performance, stability, payment flows, and developer productivity in collaborative distributed teams.

At Guava Pay, I own in-app chat development for a digital banking app, delivering real-time text, audio, and video messaging alongside wallet creation and balance top-ups directly in chat.

I replaced legacy third-party UI with a native Compose and MVI solution, migrated 50 XML layouts, and improved stability to 99.2% crash-free with stronger error handling and around 300 unit tests. I also integrated an AI-powered support agent that doubled message-processing speed and implemented biometric login and transaction confirmation.

Previously at NSPK, I built an Android application from scratch for acquiring-terminal testing, including NFC payment flows using IsoDep and TLV. I later contributed to MirPay, improving performance and transaction processing speed by more than 50% for an app with 8+ million users.

My earlier work spans application protection, Gradle plugins, CI/CD, functional testing, and the IBank2 fintech application for businesses. I work across Kotlin, Java, Clean Architecture, Coroutines, secure payments, and distributed Agile teams.

Experience

Work history, roles, and key accomplishments

GL

Current

Android Developer

Current

Guava Pay Ltd

Jun 2023 - Present (3 years 2 months)

Owned development of in-app chat functionality in a digital banking application, including real-time messaging and financial flows. Improved stability to 99.2% crash-free and migrated UI to Compose and MVI.

Kotlin Coroutines Flow Clean Architecture Compose Firebase Appsflyer COIL ExoPlayer ML Kit CameraX Gradle Jira

Education

Degrees, certifications, and relevant coursework

MM

Moscow State University of Railway Engineering (MIIT)

Diploma, Computer Software Engineering

Earned a diploma in Computer Software Engineering from Moscow State University of Railway Engineering (MIIT) in 2013.

Tech stack

Software and tools used professionally

Retrofit

GitLab

JaCoCo

SendBird

Jenkins

GitLab CI

Spring Boot

Android SDK

Redis

Jira

Gradle

Java

Kotlin

XML

ExoPlayer

RabbitMQ

WhatsApp

Firebase

JUnit

TestNG

Robolectric

Mockito

TeamCity

AppsFlyer

Jetpack

Fingerprint

Android

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