Bartlomiej is available for hire
Hire BartlomiejBartlomiej Obecny
Verified Expert in Engineering
Full-stack Developer
Szczecin, Poland
Toptal member since April 16, 2014
Bio
Bartlomiej is a true enthusiast for unsolved problems. He is a full-stack developer with more than 15 years of professional experience. Bartlomiej enjoys working with people, is not afraid of changes, is very good at interpersonal skills, and is always open to new challenges.
Portfolio
European Commision
PHP, Symphony, MySQL, JavaScript, Angular 17, Angular
Sentry View Systems via Causeway
C#, C#.NET, JavaScript, TypeScript, ONVIF, Apache Kafka, WebRTC, MediaMtx...
Dolby Laboratories - Main
TypeScript, Chromecast, JavaScript, Front-end, Jira, HTTP Live Streaming (HLS)...
Experience
- JavaScript - 20 years
- CSS - 20 years
- SQL - 16 years
- Agile Software Development - 15 years
- Node.js - 11 years
- Over-the-top Content (OTT) - 6 years
- WebRTC - 4 years
- React - 4 years
Preferred Environment
Git, IntelliJ IDEA, OS X
The most amazing...
...thing I've coded was Fly3D routing between any points on a map.
Work Experience
Senior Full-stack Developer
2025 - 2025
European Commision
- Developed an internal app for the European Commission using Angular on the front end and PHP with Symphony on the back end.
- Improved advanced search, cutting down time from more than 30 seconds to less than 1 second.
- Improved several internal apps, adding new features and maintaining fixes.
Technologies: PHP, Symphony, MySQL, JavaScript, Angular 17, Angular
Video Expert
2024 - 2024
Sentry View Systems via Causeway
- Built live streaming solutions for PTZ cameras using MediaMTX and developed a custom WebRTC player.
- Implemented recording storage using MinIO, a distributed S3-compatible storage system.
- Created a framework that enabled any gamepad to control and steer PTZ cameras.
Technologies: C#, C#.NET, JavaScript, TypeScript, ONVIF, Apache Kafka, WebRTC, MediaMtx, Blazor WebAssembly, Blazor, FFmpeg, HTTP Live Streaming (HLS), RTP, MinIO, Gamepad API
Chromecast, TypeScript, and Video Developer
2022 - 2023
Dolby Laboratories - Main
- Developed and improved the video player by integrating WebSockets player and Shaka player, allowing users to pause, resume, or rewatch live content for an enhanced and seamless experience.
- Contributed to an XCD project focused on optimizing movie downloads for improved stability, employing three different CDN servers to mitigate potential failures.
- Architected a new Chromecast-integrated app for NBC, seamlessly integrating with the SKY player and successfully launching it in 2022, replacing the outdated app.
- Managed and enhanced an existing NBC app for Chromecast, implementing new features and ensuring its functionality.
Technologies: TypeScript, Chromecast, JavaScript, Front-end, Jira, HTTP Live Streaming (HLS), MPEG-DASH, Widevine, WebAssembly (Wasm)
JavaScript and Video Expert
2021 - 2022
WarnerMedia
- Developed HBO Max for different platforms (TV, boxes), integrating a video player.
- Implemented the OIPF player for TV and integrated it with an existing player.
- Added a pre-caching movie that users can potentially watch to speed up the start time of the video.
- Architected and refactored many elements of HBO Max.
Technologies: JavaScript, TypeScript, Digital Rights Management (DRM), Video Streaming, WebGL, Lightning Components, Open IPTV Forum (OIPF), Tizen, Visio, SolidJS
Full-stack Developer
2020 - 2021
Lyra Entertainment Inc.
- Developed and designed the back end, database, and front end for a new music and video streaming app.
- Built an admin panel back end and front end with the possibility of converting music and video and uploading automatically to Amazon S3.
- Managed front-end development, helping recruit developers and perform code reviews.
- Set up all infrastructure, initially on dedicated servers, and later migrated to AWS.
- Created the front end in Ionic and React, which was used on the web, iPhone, and Android.
Technologies: JavaScript, Node.js, Nginx-rtmp, WebRTC, NGINX, Streaming, Music Streaming, Full-stack Development, Ionic
Senior JavaScript Developer
2019 - 2021
LightStep (via Toptal)
- Maintained the OpenTelemetry API in JavaScript for both Node.js and browser.
- Contributed to developing OpenTelemetry JavaScript. Created many parts of OpenTelemetry, including tracing and metrics.
- Released stable tracing version 1.0 and experimental for metrics.
- Reviewed many pull requests from many different contributors.
- Developed all main plugins for the web and also many plugins for Node.js.
- Created the most popular exporter, Collector Exporter, for OpenTelemetry JavaScript for tracking and metrics.
Technologies: TypeScript, JavaScript, Node.js, Analytics, Full-stack, Architecture, Software Architecture, Full-stack Development
Senior JavaScript Developer
2019 - 2020
Infinity Lending Systems (via Toptal)
- Created the front-end prototype for a new payment system using TypeScript, Angular 8, and Angular Materials.
- Created a standalone component for taking payments that can be embedded into any website.
Technologies: Azure, SQL, TypeScript, Angular Material, Angular, Full-stack, Architecture, Software Architecture
React Expert
2019 - 2019
Reddit (via Toptal)
- Created a video module for the admin panel for approving videos. The video module supported different filters, generating thumbnails without a back end.
Technologies: Canvas, Video Streaming, Redux, React, TypeScript, Architecture, Software Architecture
Full-stack Engineer
2018 - 2019
FastSwims (via Toptal)
- Built a working product from scratch to organize swimming competitions in the USA.
- Created a whole back end using Node.js and Sequelize.
- Created a front-end SPA using React, Redux, and Saga.
- Integrated with payment systems and Mixpanel analytics.
- Created converters for swimming results that comply with USA Swimming Data Interchange format.
- Created auto import of swimming results from an external web page.
Technologies: Amazon Web Services (AWS), Sass, PostgreSQL, Relational Database Services (RDS), Sagas, Redux, React, Sequelize, Node.js, Full-stack, Architecture, Software Architecture, Full-stack Development
Senior JavaScript Developer
2018 - 2018
Video Chat
- Created a Video.js plugin for WebRTC livestreaming video integrated with Wowza Servers.
Technologies: Video.js, Wowza, JavaScript, WebRTC, Full-stack, Architecture, Software Architecture
Senior JavaScript Developer
2016 - 2018
Castlabs
- Created DOWNStream for Electron, an open-source project for downloading DASH movies.
- Created a desktop app for downloading movies based on Electron and React.
- Worked on ongoing development of PRESTOPlay for browsers.
- Implemented smooth streaming.
- Created a video tracking plugin for Video.js.
- Integrated analytics for "conviva" and "nice people at work."
- Implemented Chromecast sender and receiver.
- Created util for processing subtitles which were images using canvas and then to be able to change the color of subtitles.
Technologies: Encrypted Media Extensions (EME), Node.js, Electron, Video Streaming, JavaScript, Full-stack, Architecture, Software Architecture, Full-stack Development
Freelance Node.js Developer
2016 - 2016
Slash-hyphen (via Toptal)
- Added a few new features to a Slack bot.
Technologies: JavaScript, Node.js, Emacs, Botkit, Full-stack, Architecture, Software Architecture
Freelance Senior JavaScript Application Engineer
2016 - 2016
Placester (via Toptal)
- Created a Node.js service for importing contacts.
- Created a new extendable modal.
- Integrated with Localytics.
- Created a module for partner scripts so that they can inject HTML fragments and custom scripts.
- Fixed many bugs and improved stability in the admin panel.
Technologies: Node.js, PHP, CSS3, HTML5, Less, Marionette.js, Backbone.js, JavaScript, Full-stack, Architecture, Software Architecture, Full-stack Development
Owner and Freelance Developer
2013 - 2016
FIOBE
- Developed an AngularJS app for file sharing.
- Worked on presentations for a mobile conference.
- Worked on video and audio streaming based on Node.js and DynamoDB.
- Worked on a document data flow app, using Node.js and AngularJS.
- Created a finance report and statistics web app using Node.js, AngularJS, PostgreSQL, and HighCharts.
- Worked on a new responsive web app for ING Bank Śląski using Marionette, Backbone, and Node.js.
Technologies: Python, Thymeleaf, Java, Linux, Git, jQuery, PHP, Bootstrap, Sass, CSS, HTML5, Bower, Gulp, Grunt, AngularJS, Full-stack, Software Architecture
Freelance Senior Front-end Developer
2014 - 2015
ConsumerAffairs.com (via Toptal)
- Created a vanilla JS library for for toggling and shuffling elements on the page.
- Improved the build process using Gulp, Jasmine unit tests, and documentation using JSDoc.
- Integrated with Segment.io and Mixpanel.
- Used a TypeForm to collect data about pet quizzes and then presented aggregated data on a custom SVG chart.
- Refactored campaign pages and brand pages.
- Optimized the generation of emails using improved SQL queries and stored procedures.
- Built a pure CSS solution for star ratings.
- Refactored the Ouibounce library (exit intent) to work on mobile, also adding some improvements.
- Integrated action forms.
Technologies: JSDoc, Typeform.io, Jinja, Branch.io, Highcharts, Bash, CircleCI, Karma, Jasmine, Mixpanel, Google Analytics, MySQL, Python, Django, Handlebars, Gulp, Backbone.js, AngularJS, Sass, Stylus, CoffeeScript, JavaScript, Full-stack, Architecture, Software Architecture
Freelance Developer
2014 - 2014
FindTheBest (via Toptal)
- Created a prototype app using AngularJS.
- Integrated with family search API using a third-party SDK.
Technologies: Bootstrap, AngularJS, JavaScript, Full-stack, Architecture, Software Architecture
CTO
2012 - 2013
Starters
- Created an HTML text editor in vanilla JS.
- Developed a web app for taking notes using PHP 5, JavaScript, and Python.
- Prototyped an e-learning platform using Java and HTML5.
- Prototyped using Mockflow.com.
Technologies: MySQL, PostgreSQL, Apache, Debian Linux, Git, jQuery, Python, PHP 5, JavaScript, CSS, HTML5, Full-stack, Architecture, Software Architecture, Full-stack Development
Senior Engineer
2009 - 2012
Nokia Gate 5
- Worked on creating a route between points on a map using JavaScript.
- Developed a traffic data visualization and public transportation routing using JavaScript and REST.
- Developed Flying 3D, a simulator for any route, using JavaScript.
- Developed an interface for on-map weather information, using Java, Python, and JavaScript.
- Developed a build stats tool for Jenkins in Python.
- Tested with Jasmine, JBehave, and Cucumber.
- Applied continuous integration using Jenkins, Maven, and Puppet.
Technologies: Varnish, Splunk, Git, Subversion (SVN), Continuous Integration (CI), Puppet, Jasmine, JBehave, Behavior-driven Development (BDD), Test-driven Development (TDD), jQuery, Scrum, Agile, Apache Maven, Python, Java, JavaScript, CSS, HTML, Full-stack, Architecture, Software Architecture, Full-stack Development
Senior Developer
2009 - 2009
Web Solutions
- Helped develop a search module for over 500 domains.
- Developed a multi-threading service for domain search using C# IIS.
- Developed an administration panel for office support.
- Developed a payment gateway with credit cards, using REST and C#.
- Used Mono framework.
Technologies: EPPlus, XML, SMTP, HTTP, Web Services, MySQL, C#, Visual Basic, Mono, ASP.NET, Visual Basic for Applications (VBA), Microsoft Visual Studio, Ajax, Test Cases, JavaScript, XHTML, Subversion (SVN), IIS, .NET, Full-stack, Architecture, Software Architecture, Full-stack Development
Team Leader
2007 - 2009
Where Are You Now
- Implemented a new mailbox using data migration, C#, and JavaScript.
- Developed geolocations—a map point and Google Maps—creating a new database for towns from all over the world.
- Developed contact imports from an address book, optimizing an existing mechanism.
- Implemented full search using Visual Basic and MS SQL.
- Developed Carbon Footprint, calculating the amount of GHG (greenhouse gas) emissions caused directly and indirectly by traveling around the globe.
- Developed Friends Book, a module for keeping in touch with friends. Implemented many changes and optimizations.
Technologies: XML, SMTP, HTTP, Web Services Description Language (WSDL), Scrum, FTP, Web Services, CSS, Visual Basic 6 (VB6), OpenVPN, MySQL, ASP.NET, Microsoft SQL Server, Active Server Pages (ASP), Subversion (SVN), Ajax, SQL, JavaScript, XHTML, SOAP, IIS, .NET, Full-stack, Architecture, Software Architecture, Full-stack Development
Web Developer
2006 - 2007
Where Are You Now
- Worked on an integration with Virtual Earth and Google Maps, using JavaScript.
- Developed a trip profile page and a travel guide using JavaScript and CSS,.
- Worked on integration with third parties using web services and SOAP.
Technologies: XML, SMTP, HTTP, Web Services Description Language (WSDL), FTP, Web Services, CSS, Visual Basic 6 (VB6), OpenVPN, MySQL, ASP.NET, Microsoft SQL Server, Active Server Pages (ASP), Subversion (SVN), Ajax, SQL, JavaScript, XHTML, SOAP, IIS, .NET, Full-stack, Architecture, Software Architecture, Full-stack Development
Owner and Freelance Developer
2000 - 2007
COBO
- Developed a web application for document flows inside the company, using PHP, JavaScript, CSS, and Ajax.
- Built client/server applications for managing documents flows between architects, such as time sheets, costs, reminders, reports, LAN chat, and progress for each project, using Delphi and dBase.
- Created a data warehouse for a company which sells steel pipes. Used PHP, JavaScript, CSS, and MySQL.
- Programmed applications to generate statistics for the National Lottery. Used Delphi and dBase.
- Developed a client/server application for managing and controlling the computers in an Internet Café. Used Delphi, TCP/IP, and UDP.
- Built an application for managing a cemetery, using Delphi and dBase.
Technologies: dBASE, Apache, CSS, HTML, JavaScript, Ajax, MySQL, PHP, Software Architecture
Software Developer
2005 - 2006
Agryf S.A. - Animex Group
- Created reports with a custom app, implemented with Delphi, dBase, and Firebird.
- Made reports for various departments, using Delphi, dBase, Firebird, and Oracle 8i.
- Administrated the company network, using Novell, DHCP, and SSH.
- Developed a dedicated application for reading wages using Assembly, PASCAL, and dBase.
Technologies: SMTP, FTP, Assembler, Novell NetWare, XML, Pascal, Firebird, TCP/IP, Oracle, SSH, OpenVPN, DHCP, SQL, HTTP, Delphi
Software Developer
2005 - 2005
Public Hospital
- Developed various small apps using Delphi and dBase.
- Performed server administration in Novell, UNIX, Oracle, and Informix.
- Developed the web page using JavaScript, CSS, HTML, MySQL, and PHP.
- Implemented a daily work scheduler using PHP, Delphi, MySQL, and JavaScript.
Technologies: CSS, HTML, JavaScript, PHP, Linux, IBM Informix, Unix, SMTP, FTP, Novell NetWare, TCP/IP, Oracle, Ethernet, SSH, OpenVPN, DHCP, SQL, HTTP, Delphi
IT Technician, Software Developer
2001 - 2002
Aeris Computers
- Created web pages using JavaScript, HTML, and CSS.
- Built new workstations.
- Helped with computer software and harder IT tasks.
- Developed a desktop app for updating warehouse, in Delphi and MySQL.
Technologies: CSS, HTML, JavaScript, PHP, SQL, Delphi
Experience
OpenTelemetry
https://github.com/open-telemetry/opentelemetry-jsA framework for collecting traces and metrics from applications. I am the maintainer for this open-source project for an OpenTelemetry API in JavaScript and TypeScript, both Node.js and browser. I created and designed the exporters, metrics, core, SDK, and plugins for auto instrumentation, including:
• XMLHttpRequest
• Fetch
• GraphQL
• Fastify
• Document load
• User interactions
• XMLHttpRequest
• Fetch
• GraphQL
• Fastify
• Document load
• User interactions
TranscendPay
Created the front-end prototype for a new payment system using TypeScript, Angular, and Angular Material.
Video Admin Module
Created a video module in the admin environment for moderating users' videos. Added various filters and controls to be able to manipulate the content. Added a module for generating thumbnails on the fly without a back end.
Tech stack: TypeScript, React, Redux, Canvas
Tech stack: TypeScript, React, Redux, Canvas
FastSwims
https://www.fastswims.com/I built the FastSwims website from scratch including the back front end.
WebRTC Video Chat
Created a WebRTC client to be used with Wowza Server for live streaming with very short response time. WebRTC client has been developed as a plugin that can be easily used with Video.js.
PRESTOPlay for Browsers
Worked on PRESTOPlay for Browsers, a video player for playing dash, smooth streaming, and HLS protected content through popular browsers.
DOWNStream for Electron
https://github.com/castlabs/downstream_electronAn open-source project for downloading DASH movies.
Technologies: JavaScript, Node.js, Electron
Technologies: JavaScript, Node.js, Electron
Placester
http://placester.comI worked on the admin panel for placester.com, which is a data company in the real estate industry. I have also created a new service in Node.js for importing contacts.
Responsive Web App for ING Bank Śląski
Worked on a new responsive web app for ING Bank Śląski using Marionette, Backbone, and Node.js.
Consumer Affairs
I worked on the Consumer Affairs website, which includes consumer news, recall information, and tens of thousands of pages of consumer reviews.
Family Tree Builder
I created a prototype integration with Family Search API using AngularJS.
Video Live Streaming
An app that shows live video streams on the web.
Back-end tech: Node.js, AWS, Elastic Beanstalk, Amazon SDK, EC2, Powershell, DynamoDB, FFMpeg, Wowza
Front-end tech: Angular, HTML5, Canvas, AudioContext, FFMpeg, Web sockets, Web workers
Back-end tech: Node.js, AWS, Elastic Beanstalk, Amazon SDK, EC2, Powershell, DynamoDB, FFMpeg, Wowza
Front-end tech: Angular, HTML5, Canvas, AudioContext, FFMpeg, Web sockets, Web workers
Document Data Flow
An app for document flow in a company with some reports. Used Node.js, PostgreSQL, Angular, HighCharts, and a dedicated server with Proxmox openVZ.
Finance Reports and Statistics
A web application for generating reports for finance metrics and statistics. Used AngularJS, Node.js, HighCharts, and PostgreSQL.
File Sharing
I built a front-end app for file sharing. Used Angular, Grunt, Karma, Jasmine, and Bootstrap.
Notekick
I created a startup, a web app for taking notes.
Nokia Maps
I helped develop maps.nokia.com, now known as here.com. Mostly worked on routing.
Danish Domain Registrar
http://web-solutions.eu/I worked on a web-based system for internet domain registration and management.
Angular i18nT
https://github.com/obecny/i18nTThis is an Angular translation module, with custom filters for different languages and support for different grammar cases.
Intelligent House
My thesis in technical school: “Using Computers to Manage Domestic Appliances at Home."
I created and designed some electronic devices, which you could connect in clusters of up to 8. Six of them were similar to on/off switches, and two also had possibilities to change the power.
This electronic device cluster was plugged into computers using parallel ports, and windows-based application were able to manage those 8 devices. There were several possibilities for automatic management, including randomized signals. The main idea was to protect the user's home against burglars while he was away.
I received the "Technician of the Year" state award in Poland for this project, in 2000.
Technologies: C++, Bascom, Assembler, Dbase, Protel, Circuit Simulator
I created and designed some electronic devices, which you could connect in clusters of up to 8. Six of them were similar to on/off switches, and two also had possibilities to change the power.
This electronic device cluster was plugged into computers using parallel ports, and windows-based application were able to manage those 8 devices. There were several possibilities for automatic management, including randomized signals. The main idea was to protect the user's home against burglars while he was away.
I received the "Technician of the Year" state award in Poland for this project, in 2000.
Technologies: C++, Bascom, Assembler, Dbase, Protel, Circuit Simulator
Slash-hyphen
I worked on improvements for Slackbot.
Surveillance Monitoring Solution
I built a live streaming solution for PTZ cameras using MediaMTX and developed a custom WebRTC player. I implemented recording storage using MinIO, a distributed S3-compatible storage system. I also created a framework that enabled any gamepad to control and steer PTZ cameras.
Education
2000 - 2005
Master's Degree in Computer Science and Econometrics
University Of Szczecin - Szczecin, Poland
1995 - 2000
College Degree in Electronics
Technical School in Slupsk (College) - Slupsk, Poland
Skills
Libraries/APIs
React, jQuery, Node.js, REST APIs, WebRTC, Redux-Saga, Shaka Player, HTML5 Web Workers, Backbone.Marionette, Underscore.js, Backbone.js, EPPlus, Handlebars, Highcharts, Typeform.io, Marionette.js, Google Cast API, Puppet.js, Amazon API, React Redux, Nginx-rtmp, WebGL, SolidJS, FFmpeg, Gamepad API
Tools
Webpack, Git, Stylus, Gulp, Slack, GitHub, Karma, Bower, Mercurial, Grunt, Sequelize, Jira, ChatGPT, Apache, Puppet, Subversion (SVN), Splunk, Varnish, Microsoft Visual Studio, OpenVPN, Novell NetWare, IntelliJ IDEA, Google Analytics, CircleCI, Branch.io, Emacs, Canvas, Botkit, Wowza, Adobe Photoshop, Apache Maven, Eclipse IDE, NGINX, Visio, ONVIF
Languages
Sass, TypeScript, ECMAScript (ES6), SQL, Less, HTML5, CSS, JavaScript, HTML, JavaScript 6, JavaScript 5, CSS3, PHP, Bash Script, CoffeeScript, Markdown, PHP 5, XHTML, Visual Basic for Applications (VBA), XML, Active Server Pages (ASP), Visual Basic 6 (VB6), Web Services Description Language (WSDL), Delphi, Pascal, Assembler, dBASE, Bash, Java, C#, Python, Visual Basic, C#.NET
Frameworks
Video.js, Jasmine, Bootstrap, AngularJS, Redux, Jinja, Ionic, JBehave, Express.js, Yii, Angular Material, Angular, Electron, Lightning Components, .NET, ASP.NET, Django, Hibernate, Spring, Mono, Thymeleaf, Jest, Blazor WebAssembly, Blazor, Angular 17, Flutter
Paradigms
Responsive Web Design (RWD), Scrum, Design Patterns, Continuous Deployment, Continuous Integration (CI), Unit Testing, Agile Software Development, Object-oriented Programming (OOP), Web Architecture, Database Design, Testing, RESTful Development, Test-driven Development (TDD), Behavior-driven Development (BDD), E2E Testing, Continuous Delivery (CD), Continuous Development (CD), Agile, MEAN Stack
Platforms
MacOS, iOS, Amazon EC2, AWS Elastic Beanstalk, Linux, Debian Linux, Tizen, Oracle, Unix, OS X, Mixpanel, Azure, Web, Windows, WordPress, Amazon Web Services (AWS), Music Streaming, Apache Kafka, Docker
Storage
PostgreSQL, MySQL, SQL Architecture, Firebird, IBM Informix, Amazon DynamoDB, Memcached, Microsoft SQL Server, NoSQL
Industry Expertise
Open IPTV Forum (OIPF)
Other
HTML5 Video, Media Source Extensions, Encrypted Media Extensions (EME), Web App Development, Code Architecture, Architecture, RESTful Web Services, Full-stack, Web Development, Over-the-top Content (OTT), Software Architecture, Full-stack Development, Chromecast, HTTP Live Streaming (HLS), Smooth Streaming, Video Streaming, UI Testing, UI Frameworks, Team Leadership, Smart TV, Lighting, Cursor AI, Vibe Coding, IIS, Test Cases, Ajax, Web Services, HTTP, SMTP, SOAP, FTP, DHCP, SSH, TCP/IP, Ethernet, JSDoc, Sagas, Relational Database Services (RDS), UX Architecture, Scraping, Technical Leadership, Analytics, Computer Science, Electronics, Streaming, Digital Rights Management (DRM), Front-end, MPEG-DASH, Widevine, WebAssembly (Wasm), MediaMtx, RTP, MinIO, Symphony, minio
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