Md Ashfaq Salehin, Developer in London, United Kingdom
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Md Ashfaq Salehin

Verified Expert  in Engineering

Full-stack Developer

Location
London, United Kingdom
Toptal Member Since
October 31, 2018

Ashfaq is a full-stack software engineer experienced in multiple programming languages, specifically Java, Kotlin, Python, and JavaScript. He is a back-end heavy full-stack developer but also experienced in front end. Additionally, he has experience in native Android and cross-platform mobile application development. He has worked for some of the largest global companies, including Meta and HelloFresh. Ashfaq is passionate about AI and holds an M.Sc. in AI from a top-ranked UK university.

Portfolio

Local Staffing LLC
Node.js, React, Elasticsearch, MongoDB, TensorFlow, Amazon SageMaker, Python...
Meta
Android, Kotlin, Java, HTML, Docker, JSON, Microservices, APIs, Git...
HelloFresh USA
Android, Android SDK, Unit Testing, UI Testing, Continuous Integration (CI)...

Experience

Availability

Part-time

Preferred Environment

Slack

The most amazing...

...project I've worked on is the flight booking system at one of the largest travel booking companies worldwide.

Work Experience

Senior Software Engineer

2023 - 2024
Local Staffing LLC
  • Developed a large XML feed builder application using Node.js, Elasticsearch, and React.
  • Created a sentiment classification system using NLP, TensorFlow, and Amazon SageMaker.
  • Engineered a job recommendation system using NLP, TensorFlow, and Amazon SageMaker.
  • Wrote serverless Lambda functions to deploy specific functionalities.
Technologies: Node.js, React, Elasticsearch, MongoDB, TensorFlow, Amazon SageMaker, Python, Deep Learning, Natural Language Processing (NLP), Classification, CSS, HTML, BigQuery, Data Engineering, Docker, Docker Compose, JSON, TypeScript, Full-stack, Amazon Web Services (AWS), Microservices, APIs, Git, REST APIs, Relational Databases, AWS Lambda, Amazon S3 (AWS S3), MapReduce, Object-relational Mapping (ORM), REST, Firebase, Next.js, Back-end Development, Front-end Development, Front-end, Back-end, CI/CD Pipelines, Apache Kafka, Software Engineering, NoSQL, Django

Software Engineer (Android)

2022 - 2023
Meta
  • Solved cross-organization problems in Facebook, WhatsApp, and Instagram applications.
  • Maintained relationships with stakeholders in Meta's partner companies, such as Google and Samsung.
  • Integrated and maintained third-party service implementations inside Facebook and WhatsApp.
  • Oversaw the development and improvement of features inside Facebook and Whatsapp applications using Kotlin.
Technologies: Android, Kotlin, Java, HTML, Docker, JSON, Microservices, APIs, Git, Front-end Development, Software Engineering

Kotlin/Android Developer

2021 - 2022
HelloFresh USA
  • Designed and implemented multiple important features from scratch in a HelloFresh Android application using Kotlin.
  • Helped in the transition of architecture from MVP to MVI.
  • Wrote mocked UI tests using the Espresso framework and Kotlin.
  • Integrated internal and external backend APIs using Retrofit and Kotlin.
  • Participated in internal product design and scrum meetings.
  • Analyzed requirements and created Jira tasks and subtasks. Estimated efforts in the implementation of complex features.
  • Performed code review and hosted meetings in case of complex issues.
  • Conducted release testing for the teams to which I was assigned.
Technologies: Android, Android SDK, Unit Testing, UI Testing, Continuous Integration (CI), JSON, APIs, Scrum, Mobile Development, Git, Integration Testing, REST, Push Notifications, Front-end Development, Jetpack Compose, Android Jetpack, Software Engineering

Java/Kotlin Developer (Android)

2020 - 2021
OPN
  • Led, designed, and developed various Android applications and internal SDKs.
  • Developed a major part of the Toyota Wallet application using React Native and later Kotlin.
  • Designed and developed internal SDKs for the company, such as a storage framework and user kit using Kotlin.
  • Integrated in-house and third-party APIs using Kotlin.
  • Contributed to developing back-end APIs using the Kotlin language and the Spring Boot framework.
Technologies: Kotlin, Android SDK, RxJava, Dagger 2, Hilt, JUnit, React Native, JSON, Microservices, APIs, Mobile Development, Git, Payment APIs, Integration Testing, REST, Firebase, Push Notifications, Front-end Development, Back-end, Android Jetpack, Software Engineering

Senior Software Engineer

2019 - 2020
Agoda
  • Worked on the flight post-booking system developed using Scala and the Spring Boot framework.
  • Developed additional back-end APIs using Java and the Spring Boot framework.
  • Developed front-end application features using JavaScript and React.
  • Built log analytic systems using Scala, Spark, ELK stack, and Spring Boot frameworks.
Technologies: React, Java, Scala, Hadoop, Spark, GraphQL, Go, Jest, CSS, HTML, Data Engineering, Docker, Docker Compose, JSON, TypeScript, PostgreSQL, Full-stack, Microservices, APIs, Scrum, Git, REST APIs, Relational Databases, Spring, MapReduce, Payment APIs, Hibernate, Java Persistence Query Language (JPQL), SQL, Object-relational Mapping (ORM), Integration Testing, REST, Ruby on Rails (RoR), Spring Boot, Back-end Development, Front-end Development, Front-end, Back-end, CI/CD Pipelines, Kafka Streams, Apache Kafka, Software Engineering, NoSQL

System Developer

2018 - 2019
DIAKRIT International
  • Designed and developed various features in the company's order management system, built with Python and the Django framework.
  • Developed several REST APIs using the Laravel framework.
  • Architected the front-end shop website built with Vue.js and React.
  • Managed deployed services on the AWS cloud platform.
  • Identified bugs, created bug tickets, and communicated with other teams to help with prioritization.
Technologies: Vue, JavaScript, React, CSS, HTML, Docker, JSON, TypeScript, Full-stack, Amazon Web Services (AWS), Microservices, APIs, Git, REST APIs, Relational Databases, Hibernate, Object-relational Mapping (ORM), SQL, MySQL, REST, Back-end Development, Front-end Development, Front-end, Back-end, CI/CD Pipelines, Apache Kafka, Software Engineering, Python, Django, Laravel

Senior Full-stack Developer

2017 - 2018
VinAudit.com
  • Worked with a price summarization system from millions of car sale records using Spark and MySQL.
  • Built widgets to display car price data aggregated and summarized using Spark.
  • Created various integration scripts for client companies using our services.
  • Developed custom data feeds for important clients.
Technologies: JavaScript, PHP, CSS, HTML, Docker, JSON, PostgreSQL, Full-stack, Amazon Web Services (AWS), Microservices, APIs, Git, REST APIs, Relational Databases, SQL, MySQL, Back-end Development, Front-end Development, Front-end, Back-end, Software Engineering

Mixi | Audio Editor, Recorder, and Mixer

https://play.google.com/store/apps/details?id=com.bluehub.mixi
This personal project is an Android application for recording, editing, and mixing audio files. A limited open-source version of this application is available here: Github.com/ashfaq1701/fast-mixer.

Project Highlights:
• This is an NDK-based project. Most of the operational parts of the project are done as native codes.
• This project is built with Android architecture components, MVVM, LiveData, navigation, data binding, coroutines, and more.
• Hilt is used as a DI framework.
• RxJava and a reactive programming pattern are used to act against various view events.
• Used Google Oboe as the audio streaming framework and FFmpeg for decoding and encoding audio.

Fast Mixer

https://github.com/ashfaq1701/fast-mixer
A heavy NDK-based Android application for recording, editing, and mixing audio.

This project is done using the latest Android architecture components, MVVM, LiveData, navigation, data binding, coroutines, and more.

Key Deliverables:
• Used Hilt for dependency injection.
• Used RxJava and a reactive programming pattern to act against various view events.
• Designed some complex custom views doing heavy rendering jobs. Used RxJava observers heavily inside those views to react promptly against UI actions.
• Performed all heavy computation and IO tasks in background threads (IO Dispatcher and Default Dispatcher).

Most of the operational parts of the project are done as native codes. The solution is scalable and will allow many layers of further improvements without a significant structural refactor.
The app uses FFmpeg for decoding audio and libsndfile to write into a WAV file. and ASAN and HWASAN to track memory leaks.

Toyota Wallet (Thailand)

https://play.google.com/store/apps/details?id=com.toyotawallet.gcp
I developed this application as part of my job responsibilities while working at OPN. I built many core features of the application with native Kotlin MVVM architecture. and, as part of my job role, I owned some important features of this application.

VinAudit MarketValue

http://www.vinaudit.com/widgets/marketvalue/demo.html
This project was done using Spark, Hadoop, and Scala. This is a back-end service to calculate a summary of vehicle prices for a particular year, make, model, and trim. This deals with a huge amount of data. Each night it runs and calculates a summary of hundreds of millions of raw sales records and summarizes statistical information grouped by each year, make, model, and trim. As data can be too noisy, the system runs outlier detection on the rows to pre-filter out anomalies. It is a very dynamic back-end service. This is still under development.

Microservice Log Processor as Graphs

https://github.com/ashfaq1701/alibaba-graph-rust
This is an ongoing project for my M.Sc. in Artificial Intelligence dissertation. In this project, we process a massive volume of unformatted microservice log data (our data volume is over 15TB). It handles system resources efficiently, processing 15TB of data on a personal computer within just six hours.

After processing the data, we construct windowed graphs (of specific intervals) from this data. Then, we apply dynamic system theories and statistical manipulation of these windowed graphs. We aim to find distinguishable network states from the data by applying mathematical and statistical concepts and techniques. We will later use a graph neural network to streamline the process. The shared code implements this whole pipeline end to end.
2023 - 2024

Master of Science Degree in Artificial Intelligence

University of Sussex - Brighton, East Sussex, United Kingdom

2009 - 2013

Bachelor of Science Degree in Electronics and Communication Engineering

Khulna University - Khulna, Bangladesh

MAY 2023 - MAY 2026

TensorFlow Developer Certificate

Tensorflow

APRIL 2021 - APRIL 2024

Associate Android Developer

Google Developers

APRIL 2020 - APRIL 2022

CCA Cloudera Spark and Hadoop Developer

Cloudera

MAY 2013 - PRESENT

International English Language Testing System (IELTS)

British Council and Cambridge ESOL

NOVEMBER 2012 - NOVEMBER 2015

Cisco Certified Network Associate

Cisco System INC

Languages

Kotlin, JavaScript, Java, PHP, Python, Scala, C++, TypeScript, Java Persistence Query Language (JPQL), SQL, C, CSS, HTML, GraphQL, Go, Rust

Frameworks

Android SDK, React Native, Spring Boot, Laravel, Hadoop, Spark, Dagger 2, Hibernate, Jest, Spring, Ruby on Rails (RoR), Next.js, JUnit, Django

Libraries/APIs

React, RxJava, REST APIs, TensorFlow, Vue, Node.js

Tools

Android NDK, Git, Docker Compose, Android Jetpack, Amazon SageMaker, BigQuery, Kafka Streams

Paradigms

REST, Microservices, Scrum, Mobile Development, Unit Testing, Continuous Integration (CI), Object-relational Mapping (ORM), MapReduce

Platforms

Android, Docker, Apache Kafka, Amazon Web Services (AWS), Firebase, AWS Lambda

Storage

MySQL, PostgreSQL, Relational Databases, Elasticsearch, JSON, NoSQL, MongoDB, Amazon S3 (AWS S3)

Other

Hilt, Full-stack, Payment APIs, UI Testing, Integration Testing, English, Deep Learning, Machine Learning, Data Engineering, Back-end Development, Front-end, Back-end, Jetpack Compose, CI/CD Pipelines, Software Engineering, Computer Vision, Natural Language Processing (NLP), Image Processing, Push Notifications, Front-end Development, APIs, Computer Networking, Electronics, Classification, Regression, Time Series Analysis, Artificial Intelligence (AI), Neural Networks

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