Hossain Khan - Portrait

Hossain Khan

Software Engineer

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About Me

Iā€™m Hossain Khan, a Senior Software Engineer with over 15 years of experience, passionate about crafting intuitive interfaces that connect people through technology. Currently, Iā€™m at Slack, enhancing the Android app with a focus on Slackā€™s platform improvements like BlockKit, Workflows, Slack Apps, and more. My career began as a web developer and has since evolved into mobile technologies, where I thrive on tackling challenging projects.

Always eager to learn and try new things, I have worked on diverse Android projects ranging from streaming media to e-commerce to hardware integration for smart connected devices. Recently, I've been investing heavily in learning AI tools and development workflows, exploring platforms like Claude Code, Gemini CLI, Cursor, GitHub Copilot, and GitHub Spark. This AI-assisted approach has revolutionized my development process, enabling rapid prototyping and innovative solutions showcased in my Vibe Coded Artifacts.

Beyond code, continuous learning and creativity come from tech news, TED Talks, and YouTube. I'm particularly fascinated by the intersection of traditional software development and emerging AI capabilities. Feel free to reach out for mentorship or collaboration on AI-assisted development projects. Letā€™s connect on exciting opportunities or ideas!

Latest Projects

Android TRMNL Display Mirror

Mirrors existing TRMNL device display image onto your Android device.

Android TRMNL Display Mirror App Banner Image

TRMNL is an e-ink companion that helps you stay focused. This is a simple Android app that mirrors the content of a TRMNL e-ink display on your phone or tablet. It connects to the TRMNL/BYOS API to fetch the current screen image and shows it on your device. The app automatically refreshes the display on a schedule and also supports manual ā€œnextā€ updates. It works with custom TRMNL or BYOS server endpoints and logs each refresh event.

  • Automatic periodic screen updates with adaptive refresh intervals (based on server config).
  • Manual refresh and ā€œnext imageā€ controls for on-demand updates.
  • Support for custom TRMNL/BYOS server URLs (for self-hosted setups).
  • Refresh history logging for monitoring and verification.
View on GitHub TRMNL LogoGet your TRMNL

Weather Alert

Your no-fuss, personal weather alerter.

Android Weather Alert Project Banner Image
Public

Set it and forget itā€”get alerted when it matters!

Weather Alert is a simple, no-frills app designed to notify you when specific weather conditions meet the thresholds you set. Whether itā€™s a snowy driveway or a rainy day, stay ahead with timely alerts that help you prepare with ease.

  • šŸŒØ Custom Alerts for Specific Weather Conditions
  • šŸŒ Choose Your Data Source & Add Your Own API Key
  • ā° Set Your Alert Frequency
  • šŸ›  Minimalist Interface
Get it on Google Play™ Learn More

Remote Notify - Device Monitor

Your personal Android device watchdog!

Remote Notify Project Banner Image
Public

Never let your remote devices die on you again! Whether you're managing one device or many, stay alert when battery or storage levels drop too low.

Install the app on each device you want to monitor, pick your preferred notification method, and get alerts when the threshold is met.

  • šŸ”‹ Real-time Monitoring: Track battery and storage levels on the home screen.
  • šŸ“² Custom Alerts: Set triggers for battery (%) or storage (GB).
  • šŸ›”ļø Multiple Notification Methods: Email, Twilio (SMS), Telegram, REST webhooks, etc.
  • āš™ļø Flexible Settings: Choose check intervals like 30 mins or a custom schedule.
  • šŸ“Š Detailed Stats: View notification history and level changes.
  • šŸ’” Dark & Light Mode: Enjoy a modern Material 3 design in both themes.
Get it on Google Play™ Learn More

Android Keep Alive (Experimental)

A simple app to keep specific apps alive by checking if they are running. If not, they will be started for you.

Android Keep Alive Project Banner Image
Alpha

This app is designed with a very specific use case in mind. It is important to understand what this app does and how.

  • App is designed to be always running in the foreground to watch and restart other applications.
  • App is NOT optimized for battery and will cause high battery šŸŖ« drain. Ideally, this should not be used on your primary phone that you use daily.
  • ā„¹ļø I use this on a secondary phone plugged into a power cable 24/7.
  • App contains some additional features like Remote Logging and Heartbeat due to my personal needs. However, the app can be used without using those features.

See the permission section in the README to better understand the app and it's functionalities.

Test drive Learn More

H.K. Vision Plugin for Muzei

A simple Muzei Live Wallpaper plugin for my H.K. Vision photography site.

H.K. Vision Muzei Plugin for Android
Beta

"Vision Muzei Plugin" is an Android plugin for my H.K. Vision photography site. The plugin app allows users to use the featured photos as background wallpaper on their Android phone that automatically changes over time.

To get advantage of this plugin, you must install the Muzei Live Wallpaper app on your phone. Once installed, you can then install this plugin and the H.K. Vision featured photos will show as a "source" inside the Muzei app.

Here is an example, where it shows how the H.K. Vision image source shows inside the Muzei app & how you can select photo and customize it:

H.K. Vision Muzei Plugin for Android Demo Screenshots
Demo

The application is Open Source and available in Github. If you have a similar source, you may also be interested in creating a plugin for it

Get it on Google Play™ Read more on Medium

Vibe Coded Artifacts

Projects built with AI-assisted development and modern vibe coding techniques, showcasing rapid prototyping and innovative solutions.

Android Keep Alive

A simple app to keep specific apps alive by checking if they are running and restarting them automatically

Android Kotlin Services
View on GitHub

Android Device Catalog

Interactive browser for exploring and analyzing Android devices from the official Device Catalog

React TypeScript Vite
See Android Catalog

JSON5-Kotlin

Robust JSON5 parser and serializer for Kotlin with modern architecture and type safety

Kotlin JSON5 Serialization
View Library Docs

Canadian Mortgage Accelerator

Interactive mortgage calculator with acceleration strategies to help Canadian homeowners pay off mortgages faster

React TypeScript Charts
Calculate Mortgage

Social Sync

Python-based tool to automatically sync posts from Bluesky to Mastodon with GitHub Actions automation

Python API Automation
View on GitHub

More Coming Soon

Additional vibe coded projects are in development

pen-Source and Other Projects

SQLDelight 2.0 with PostgreSQL

A sample project exercising PostgreSQL with SQLDelight 2.0 on JVM This is an exploration of the official guide with the intention of filling in missing pieces.

See the sample

JSON5-Kotlin

A robust JSON5 parser and serializer for Kotlin that extends JSON with helpful features like comments, trailing commas, and unquoted keys while maintaining full backward compatibility with JSON.

See the library

Yet NOT Another Android Syntax Highlighter (YNAASH)

Explore well established web based syntax highlighter like PrismJS and highlight.js, and showcase technique on how anybody can quickly incorporate these into their Android project by following some examples provided in this project.

See demo

Hangouts.json Parser - Kotlin

Kotlin based JSON parser for Google Takeout dump of Hangouts chats. It uses Moshi JSON library to model the JSON objects using kotlin classes and also uses SQLDelight library to insert parsed database into SQLite database for further analysis.

See example

Android Recycler View - Wrap Content

This is a sample android app which demonstrates `RecyclerView` wrap_content inside `ScrollView` issue on Marshmallow, Nougat and Oreo (API 23, 24, 25 & 26) and how to work around it.

See it in action

Medium.com API Specification

API spec for medium.com using OpenAPI Specification (aka Swagger 2.0). Generates PHP, Java, Python, Go, Android, Objective-C and many more client SDK.

Find out more

Android Tooltips UI Widget

Simple to use library for Android, enabling to add a tooltip near any view with ease.
Contributed to the library to provide maximum flexibility on styling TextView and animation. The new release with additional feature was packaged as v1.0.10

See changelog.

Mock API Server using Firebase

Created an example project to showcase how Firebase platform can be used to serve mocked API responses using Express.js and Firestore.

See mocked sample APIs

Miscellaneous Small Open Source Contributions

JakeWharton/adb-event-mirror - Mirror the touch/key/button events of one device onto one or more other devices in real-time

  • Reported Issue: Event forwarding did not work for same emulators #13

android/sunflower - A gardening app illustrating Android development best practices with Android Jetpack.

  • Pull-Request: Added Bengali translation for Sunflower app. #621

android/user-interface-samples - Multiple samples showing the best practices in the user interface on Android.

  • Pull-Request: People (bubbles): Fixed `ClassCastException` when trying to open `VoiceCallActivity` #188

romannurik/muzei - Muzei Live Wallpaper for Android

  • Reported Issue: Selecting image from `BrowseProviderFragment` only sets the wallpaper once #673
More on GitHub

Work Experience

Senior Software Engineer | Android - Slack LogoSlack Technologies, Inc. (2021 - Present)

Joined Slack to help them do what they do best! Making working life simpler, more pleasant & fun, and more productive. šŸ™Œ

Working with the Slack Platform Team to support over 1 million developers and 750,000+ apps that are used by millions of users every day.

Key responsibilities includes:
  • Developing user-centric and intuitive app interfaces using Slackā€™s UI framework, Block Kit.
  • Creating workflows and automations that streamline work processes and improve productivity using Slackā€™s Workflow Builder and App Home.
  • Leveraging Slackā€™s developer tools and APIs to connect with various apps and services, such as Google Calendar, Salesforce, Zoom, and more.
  • Testing, debugging, and deploying API updates for new Block Kit blocks and block elements.
  • Collaborating with other developers and stakeholders using Slackā€™s channels, threads, actions, and shortcuts.
Key Accomplishments
  • Actively participated in the Platform 2.0 initiative, specifically developed link trigger and shortcut implementation that allows customers to easily share and run 2.0 workflows from anywhere like channel, bookmarks, canvas and more.
  • Worked on brand new "File Input" block element feature that allows users to use file as input in the Block Kit and Slack App realm.
  • Organized recurring team mob sessions to improve code-base health and share knowledge among the team members.
  • Authored over dozens of wiki content for the Android Block Kit team to preserve and share the knowledge across team and organization.
Did you know?
  • Slack is a backronym and it stands for "Searchable Log of All Conversation and Knowledge".
  • Every weekday, Slack surpasses one billion usage minutes.
  • 9 hours is the time period an average user of Slack is signed in for.

Slack app on Google Play™

Platform Lead Engineer | Android - Kijiji Logo Canada, eBay (2019 - 2021)

Joined kijiji Android team to accelerate mobile product development and enhance end user experience.

  • Recently launched feature that allows users to review their buying or selling experience on Kijiji.
  • Built feature that allows Ad-ops to run campaigns for different periods of time.
  • Held bi-weekly team meeting to keep everyone in the loop with industry standards and technologies that can help grow Kijiji and it's user base.
  • Improved application crash free user session rate from 97.81% to 99.92%.
  • Took initiative to create a proof of concept (PoC) for adding šŸŒ— dark mode support to the app.
  • Improved code quality and engineering experience by taking following actions:
    • Enabled lint checks on CI build after creating a baseline.
    • Enabled Kotlin code formatting lint checks on CI build.
    • Resurrected UI Unit test on Firebase Test Lab and Jenkins using Android emulator.
    • Added new Jenkins job to distribute CI builds using Firebase App Distribution.
    • Took initiatives to introduce proper code dependency injection using Dagger2 library.
    • Advocated for using consistent MVP pattern for newly developed features
    • Introduced use of MVVM architecture pattern into project that allows engineers to use latest lifecycle aware AndroidX libraries.
    • Added technical wiki for newcomers on application architecture, best practices, development & PR process and so on.
    • Proactively worked with the team to reduce Tech-Debt in the project. Some of recent initiatives includes - decomissioning obsolete A/B tests, upgrade build tools, migrate to R8 obfuscation tools, project-wide standardized JSON serialization, applying consistent UI for common components, and many more.
  • Led team to migrate app's API target level to Android 10, and currently working on targeting the app to Android 11 to meet Google's deadline of October 2021.
  • Participated in the company-wide hackathon and was placed 3rd šŸ„‰
  • Participated in week long world-wide eBay Classifieds hackathon competing with 10 other teams consisting of members from 8+ countries. During COVID-19, our video conference like feature for classifieds seller to reduce in-person contact won the competition šŸ„‡ that was selected by jury for most innovative, impactful and ready idea for current situation.
Did you know?
  • Four out of five Canadians (82%) participated in the second-hand economy in 2018, fuelling a $27.3 billion second-hand economy that has grown in size annually since 2015.
  • In 2018 alone, Canadians gave 2.4 billion items a second life - 250 million more items than in 2014.

Kijiji app on Google Play™

Sr. Android Engineer / Team Lead (Consultant) - Connected Inc. (2017 - 2018)

Created a complete solution for connected media device and a companion Android application to support device communication and media content discovery.

  • Used Kotlin & MVVM architecture to implement application features.
  • Added Realm for data caching and offline support.
  • Met with customer on-site and collaborated with their engineering team on different features.
  • Planned weekly sprint items and assigned resources among team.
  • Provided technical support to team members and product managers.
  • On boarded new hires and paired with them to ramp up on the project.
  • Collaborated with other platform team leads to discuss and finalize the design and architecture of different core components.
  • Reviewed code using GitHub and provided constructive feedback to be compliant with currently defined project standards.
  • Worked with Product Manager to plan and execute monthly releases to Google Play store.
  • Closely worked with the QA team to address and clarify any application-related issues.
  • Created “Developer's Guide” wiki for key components of the app, consistently encouraged other team members to contribute to it.
Key Accomplishments
  • Successfully launched the feature complete companion Android app on time.
  • Improved crash free user session from 92% to 99.2% by constantly analyzing data from Crashlytics.
  • Reduced application size by 15% by using vector images and lightweight WebP image assets
  • Reduced 8% background battery consumption on the application by using Android platform's JobScheduler.

Platform Lead | Android - dubdub Inc. (2016 - 2017)

  • Worked with management to set priorities for upcoming releases and define stories accordingly
  • Worked with UI/UX team to refine app experience
  • Initiated weekly app improvement brainstorming meeting with the team and implemented material design patterns to make UX better.
  • Supported QA team for various activities including UI test automation
Key Accomplishments
  • Added automation script to reduce manual tasks that were required during day-to-day development.
  • Improved code coverage by 7% for core components.

Sr. Android Engineer | Team Lead - dubdub Inc. (2016 - 2017)

  • Worked with management to set priorities for upcoming releases and define stories accordingly
  • Worked with UI/UX team to refine app experience
  • Initiated weekly app improvement brainstorming meeting with the team and implemented material design patterns to make UX better.
  • Supported QA team for various activities including UI test automation
  • Architected the Android app using the modern MVP pattern recommended by Google engineers. The pattern was strictly enforced among the team.
  • Participated in project planning, estimation and provided valuable feedback. Distributed planned tasks among the team members.
  • Participated in code review for features, bug fixes and other changes.
  • Designed API and translated API specification using OpenAPI Specification standard; formerly known as Swagger 2.0. The OpenAPI Specification contract was later used to generate rest-client library for respective platforms.
  • Created wiki containing technical-guide, developers-guide, and release-guide for future reference.
  • Maintained Google Play store release cycles for Alpha, Beta and Production channels.
  • Set up continuous integration (CI) using BuddyBuild for each pull-request which builds dev, staging and production builds.
  • Constantly refactored code base to adhere to DRY principle.
  • Improved application's draw performance by reducing overdraw and optimizing view hierarchy inside recycler view.
Key Accomplishments
  • Used APK analyzer to analyze APK, and optimized large image assets using WebP reducing the size by 19mb, which resulted over 58% savings on APK size.
  • Ran android lint tool, and reduced 36% of critical lint warning and errors for the project.
  • Maintained unit tests and improved code-coverage by 8% for newly added features.
  • Developed fully functional proof-of-concept Android TV(šŸ“ŗ) app that uses same API and services for video content consumption.
  • Added automation script to reduce manual tasks that were required during day-to-day development.

Sr. Android Engineer - QuickPlay Media (2015 - 2016)

Worked with R&D android development team for current and future products.

  • Refactor and enhance existing library features, provide better solution where necessary.
  • Provide and update documentation with each release.
  • Build and maintain a sample Android application to showcase supported features.
  • Write unit tests, review peer-code and provide input if applicable.

Android Engineer - QuickPlay Media(2012 - 2014)

  • Managed, helped and guided team members to achieve sprint & project goals
  • Participated in daily scrum meetings and provide updates
  • Participated in development estimations for clients or PMs
  • Improve code-base by constantly refactoring or re-using established open-source software
  • Helped different projects on-demand to fix production issues.
  • Trained new hires to work on existing projects
  • Documented project standards and process in wiki
  • Collaborated with different team to gather requirements and implementation details
  • Worked on multiple PoC phase for different clients
Key Accomplishments
  • Released android app for major Canadian carrier which has support for LIVE and VOD video streaming on the go for Android phones & tablets. The application has been optimized to run on set-top boxes and Android TV. It has 100,000 - 500,000 install from Google Play store.
  • A live streaming application using proprietary technology for a closed group of people. Worked with specific future devices that have this technology enabled.