DEV: Challenge Accepted 2023: The Road

An international technical software development conference

About The Event

DEV: Challenge Accepted is a full-day single-track conference for software developers of all levels. The conference focuses on the latest trends and technologies in the industry, providing attendees with the opportunity to learn from experienced professionals and network with their peers. It's a great opportunity for developers to stay up-to-date with the latest developments in their field and gain valuable insights from industry leaders. After the successful launch in 2022, we would like to welcome you on September 30th in Sofia Tech Park. The event will also be streamed online for free. With a focus on providing valuable content and fostering a sense of community among attendees, DEV: Challenge Accepted is an event not to be missed for any software developer.


John Atanasoff Forum
Sofia Tech Park
Sofia, Bulgaria


September 30 th 2023
Day 273 of Year 2023

The event is over.

Event Schedule



Good morning and a warm welcome! Come take your conference badge and your backpack full of presents. After that, you can kickstart your day with a freshly brewed cup of coffee.


Hello, world!

An official opening of the conference by our well-known hosts: Vladislav Violinov and Toni Karabashev.


Don't let technical debt drag you down: a guide to staying afloat

by Nedelcho Nikolov - Team Lead @ Enetpulse

  from Sofia, Bulgaria

Last year Ned kicked off his speaker's career with our conference, so this year we are kicking off with Ned! Prepare for a deep dive into a topic that every developer has grappled with - technical debt. Ned will explore what this is, why it happens, how we can prevent it, and what the consequences are if we don’t take care of the bad code we have to write sometimes. Whether you're a mid-level developer, a seasoned pro, or a leader/manager in the tech industry, this talk will provide insights that are platform/language agnostic, making it applicable to everyone in the IT industry.

Nedelcho Nikolov

Ned is a seasoned software developer with over 13 years of experience. He holds a Master's degree from the Technical University of Gabrovo and recently completed a Project Manager major at New Bulgarian University. Currently serving as a team lead at Enetpulse, Ned is passionate about new technologies and implementing best practices to improve existing codebases. With experience in a fast-paced environment where every second counts, he's well-versed in handling inconsistent traffic to products. He is also a dedicated knowledge sharer and enjoys learning new things, training, and playing games.


Coffee break sponsored by

“Life's too short for bad coffee.”
– Gord Downie


Break the ice between services

by Kiril Vuchkov - Principal Software Engineer @ Vay

  from Sofia, Bulgaria

In this talk, Kiril will talk about the challenges of effective service-to-service communication and demonstrate how Golang, gRPC, and AWS can be used to overcome them. Kiril will provide practical examples and insights into common pitfalls and best practices, making the talk valuable for backend engineers working with Golang and/or gRPC. The talk will assume some basic knowledge of backend fundamentals and will be at an intermediate level. Moreover, Kiril's talk goes beyond the basics of service communication and will provide valuable practical advice on modern (micro)service-oriented architecture. Attendees will gain an understanding of the powerful gRPC service config, the importance of server-driven retry policies, and how to incorporate detailed error handling into their APIs. Kiril will also explore the nuances of AWS Elastic Load Balancing (ELB) and share insights on how to avoid some common issues. Overall, this talk is an excellent opportunity for backend engineers to learn about the best practices and tools for effective service communication.

Kiril Vuchkov

Kiril leads the cross-functional B2C engineering team at Vay to develop the company's driverless technology for end-customers. He is responsible for driving the software architecture that spans mobile apps, APIs, distributed backends based on Golang, and integrations with a deep tech stack. Kiril also focuses on empowering other teams by developing best practices, reusable tools, and platforms. In the past he has also worked on a scalable invoicing system at Uber and partnered with enterprise customers on building private cloud solutions and developer experience at VMware. Currently Kiril is excited to develop technology that goes from mobile applications and web through APIs, distributed backend, AWS infrastructure, and even integrating it with specialized hardware installed in vehicles. Outside of work, Kiril has a few hobbies, including being a seasoned dungeon master in D&D.


Open-source: open choice - a DevOps guide for OSS adoption

by Hila Fish - Senior DevOps Engineer @ Wix

  from Tel Aviv, Israel

Choosing the right open-source project to use can be quite challenging - not knowing if it’s going to be the right fit, how it will behave, and if you end up wasting time trying to make it all work. We’ve all been there. But what if we tell you that there’s a practical way to have a clear understanding of how to incorporate an OSS project in your environment? Hila will speak about the DevOps perspective on open-source and the challenges Infra-focused engineers have with choosing the right project for their environment. As a DevOps Engineer, she has seen a lot of things, and stumbled upon a lot of non-based decisions, so she will present practical advices on how to choose an OSS project for your dev/prod environment and will talk about the business mindset you should have to evaluate the key indicators based on your needs and specific pain points. This talk is ideal for developers who want to gain insight into the DevOps perspective on OSS, DevOps and SREs who can benefit from key metrics for choosing an OSS project, and managers and tech leads who are looking to incorporate OSS into their organization. By the end of this talk, attendees will have actionable metrics and indicators that will help them choose the right OSS project for their dev/prod environment, making them more inclined to adopt OSS in their organization and amplify its impact.

Hila Fish

Hila is a Senior DevOps Engineer at Wix, with 15 years of experience in the tech industry. She is also an AWS Community Builder, Hashicorp Ambassador, and an international public speaker who believes the DevOps culture is what drives a company to perform at its best and talks about that and other DevOps/Infrastructure-related topics at conferences. She carries the vision to enhance and drive business success by taking care of its infrastructure. In her spare time, Hila is a lead singer of a cover band, giving back to the community by co-organizing DevOps-related conferences such as "DevOpsDays TLV"" and "StatsCraft" monitoring-focused event. Hila is also a mentor in the largest Israeli technical women’s community “Baot” and enjoys sharing her passion and knowledge wherever she can, including across diverse technology communities, initiatives and social media.


Coffee break sponsored by

“I am a coffee fanatic. Once you go to proper coffee, you can't go back. You cannot go back.”
– Hugh Laurie


Superpowers of browser's Web API

by Nikola Mitrović - Development Lead & Software Engineer @ Vega IT

  from Novi Sad, Serbia

When writing code for the Web, there are lots of capabilities that are offered out of the box by our browsers. If you ever wrote a File Upload component, used timers and intervals, interacted with the DOM, or stored something in the Local/Session Storage, you had to go to the MDN’s Web API docs, to find some relevant information on how to implement that code. In this talk, Nikola will explore some of the powerful built-in functionalities of browsers that are often overlooked. We will enter together into the exciting world of browser Web APIs that are not so commonly used (although they should be) and explore their incredible capabilities! This talk is suited for web developers who want to stay ahead of the curve when it comes to web development, and learning how Intersection Observer, Background Sync API, Screen Wake Lock API (and many more) can help you create better web applications that will keep users engaged and coming back for more.

Nikola Mitrović

Nikola is an experienced JavaScript Software Engineer with 7 years in the industry. He is more skilled in Front-end Development, with a high level of experience in working with Micro Front-end architecture, designing projects as a set of standalone components that include their own interfaces, logic, and storage. Nikola has developed mini-applications independently and composed them all together in the browser with different integration techniques. He is very passionate about web performance and ensuring the best possible user experience of web applications, and does not hesitate to share his knowledge - he has already spoken at several conferences such as DeveloperWeek Europe and DevBcn. Besides being a developer, he is also a snowboarder, dog-lover, wanderlust and junior salsa dancer.


Lunch break

If you are a company and want to support our lunch break, or help us otherwise, do not hesitate to contact us.
For sponsorship opportunities and everything else, you can write to us at


Optimising largest contentful paint

by Harry Roberts - Consultant Performance Engineer

  from Leeds, England, United Kingdom

Since Google announced their Core Web Vitals (CWV) initiative, being fast is more important than ever. However, despite being by far the easiest CWV to monitor, debug, and optimise—in both the lab and field—Largest Contentful Paint (LCP) is still the one that most websites struggle with. In this very practical talk, Harry will guide us to look at what exactly comprises LCP, how we might be working against ourselves, and how to make opportunistic optimisations to get ourselves back in the green (and beyond). And even if none of those terms meant anything to you, don’t worry! You’ll leave this talk fully equipped to go back to your own projects and clients and make all the improvements they’ll need. Get ready to ask for a pay rise.

Harry Roberts

With over a decade of professional experience, and eight years working as an independent consultant, Harry has been trusted by the likes of the United Nations, Google, the BBC, General Electric, and many more. Through combinations of workshops, training, audits, development, and consultancy, he has helped his clients to build and scale resilient, performant front-ends for a variety of applications. Internationally recognised as a leading expert in CSS architecture and front-end performance, Harry's job is to help companies accomplish the return on investment that web performance efforts can bring, whether that is increasing conversions, improving engagement, or growing revenues. He thrives on being a business-focused engineer, equally comfortable in front of C-level executives as he is in front of a room full of developers.


NPM library - make it right

by Alexey Matveev - Head of Frontend @ Devexperts

  from Munich, Germany

Everybody wants to write a brand-new NPM library. If you've tried it, come to discuss the best practices. If you haven't, come and learn something new! Join Alexey on a journey from idea to self-sustained activity. How to start and not lose motivation? How to convince others to use your library? What are the must-have technical requirements? But that's not all! Alexey will also reveal the key properties of a successful library and share tips on how to attract investments to your idea. So don't miss out on this exciting opportunity to take your NPM library development skills to the next level. Join us and become a library development pro!

Alexey Matveev

Alexey is a hardcore engineer who leads the entire frontend division with 60+ engineers at Devexperts company. A true tech expert, Alexey finds balance between his passion for programming and his talent for communication, enabling him to excel in the FinTech world. Alexey's ultimate mission is to build a strong, united division of engineers who work in a healthy environment of trust. He's a passionate programmer with expertise in Java, JavaScript, and Scala, and a talent for fast prototyping and solving uncommon problems. But Alexey is not all work and no play. He also enjoys living life to the fullest, with a range of exciting hobbies - cycling, running marathons of various lengths, hiking in the Alps, social dancing, piano playing (after having played the guitar previously), and even yoga! With his wealth of experience, passion for programming, and commitment to a balanced life, Alexey is an inspiring speaker who can motivate anyone to ex cel in their work.


Coffee break sponsored by

“I like my coffee like I like my humor: dark, bitter, and a little too hot to handle.”
– Unknown


From architecture to release - things we often forget or ignore

by Ilian Iliev - Software Engineer @ Lifesum

  from Sofia, Bulgaria

Creating a new service or software can be a complex process with many potential pitfalls, and we often make mistakes that can be costly in terms of both time and resources. In this talk, Ilian will present a list of points that are valuable but often ignored: from the planning and architecture phase all the way through development, deployment, and maintenance. This talk is targeted at junior and mid-level developers, as well as management personnel who want to be more aware of the entire process of generating an idea, building it, and releasing it. While it may not present anything particularly groundbreaking or new, it highlights important aspects of the process that are often overlooked, such as planning without considering integration with existing systems, failing to add metrics, or accepting user input without validation. It can also help companies improve their processes and better understand why they are doing certain things and how they can be improved.

Ilian Iliev

Ilian Iliev, Ph.D. is a software engineer at Lifesum, a digital health company based in Stockholm, Sweden. Ilian has been programming since 2003 and fell in love with Python in 2009 for its simplicity, power, and flexibility. He enjoys sharing his knowledge and helping people improve their skills, particularly novice programmers who are still struggling to pick good practices or find their way. To give back to the community, he has presented at various events, including Beginner's Day at EuroPython 2016, Workshops at HackConf 2018 & 2019, and Talk at HackConf 2021, as well as the first edition of DEV: Challenge Accepted, and many local meetups in Sofia and Stockholm. Ilian is passionate about connecting with new people, sharing knowledge, and exchanging ideas, making him a valuable addition to any tech conference. Beyond programming, he is also a lover of the sea - he is often snorkeling, fishing, and traveling with his family.


Building career of an architect: do's and dont's

by Vladyslav Plotnyk - Software Architect @ Sigma Software

  from Krakow, Poland

When Vladyslav moved from a senior developer to a software architect, he wasn't fully aware of the difference between these roles. This talk is based on his experience transitioning from developer to architect. Vladyslav will cover the fundamentals of the architect role, the challenges you may encounter being an architect, and give advice to those developers who want to choose this career path. Through this presentation, attendees will gain a clear understanding of who a software architect is and what their role entails within an organization. Vladyslav will focus on the necessary skills, knowledge, and responsibilities that an effective software architect should possess to thrive in their role. By the end of the talk, attendees will have a clear understanding of the role of a software architect. Vladyslav will also share some valuable resources and references to help the audience build a successful career as a software architect.

Vladyslav Plotnyk

Vladyslav is a software architect with over 17 years of experience in developing complex software solutions. He has strong expertise in business analysis, system design and coding. With over a decade of experience as a team lead, he is a proven technical leader, mentor, and problem solver. At Sigma Software, Vladyslav works closely with stakeholders to outline software requirements and translate them into high-level technical solutions. He provides architectural documentation to the development teams, supporting them throughout the development process. Moreover, he troubleshoots and resolves any issues that arise with application code or system design. Vladyslav's expertise and passion for his craft extend beyond his professional duties. He has taken the stage at several conferences, such as The Developers Conference in Brazil and Open Tech Week in Ukraine, sharing his insights and knowledge with the tech community.


Beer break with

"Beer is living proof that God loves us and wants us to be happy."
- Benjamin Franklin


Unintended consequences - how a series of unfortunate events lead to global failures

by Dimitar Tcholakov - Google Cloud Capacity and Management Lead @ Google Inc.

  from Seattle, WA, USA

For the final presentation of the conference, join Dimitar who will take us on an enchanting journey through the most exciting massive system failures that have impacted billions of people worldwide. With his extensive expertise, experience, and unique perspective, Dimitar will guide us through the root causes of these disasters and share his insights on how we can help prevent them from happening again, or at least minimize their impact. Not only will you gain valuable knowledge from Dimitar's presentation, but you'll also be entertained by his great storytelling. Don't miss out on this opportunity to learn from one of the most experienced professionals in the field and take home some unforgettable stories and insights.

Dimitar Tcholakov

Dimitar holds a degree from the University of Waterloo and has worked for big names like Scotiabank, BMO Capital Markets, Amazon, Microsoft, and currently, Google. His two decades of experience have taken him through the worlds of banking, e-commerce, security, and finally all of the better-known cloud providers. His expertise lies in building strong teams that not only create complex systems but also extend and support them with minimal human intervention. Currently, Dimitar is the head of Google Cloud Capacity and Management, where he leads a team of experts dedicated to providing top-notch solutions for clients. In his spare time, Dimitar loves to travel and capture the world's beauty through his camera lens. He's also a black belt in judo, and he's not afraid to bring some of that discipline and focus to his work!


Beer break with

"Beer, it's the cause and solution to all of life's problems."
- Homer Simpson


Lightning Talks

Lightning talks are a type of presentation format where speakers are given a short amount of time, five minutes or less, to present a topic or idea. If you want to speak from our stage, you will have the opportunity to do so and share your insights and ideas with a larger audience. You will be able to sign up during the event. While we try to leave the format as free as possible, consider short talks, English language and our code of conduct policy.


Closing Ceremony

During the closing ceremony we will officially give the Dev of the Year 2023 award, as well as many other gifts and prizes from our sponsors' games and raffles. See who the nominees are and vote now:


Afterparty preparation

We need a little time to transform the conference hall into a party area. Grab a beer, and we will likely invite you for the afterparty before you have finished it.



If you are a company and want to support our afterparty, or help us otherwise, do not hesitate to contact us.
For sponsorship opportunities and everything else, you can write to us at



We all need to leave the building by 21:00h. Thank you and goodbye!


Here is the an approximate roadmap of important conference dates. Please note that some of these dates may change:

Event officially announced on the website

Call for sponsors opened.
Call for volunteers opened.
Nominations for Dev of the Year opened.


20 Jan
Website updated

Call for papers opened
Super early bug tickets on sale
Only 50 tickets available


15 Feb
Super early bug tickets sale ends

Early bug tickets on sale
Only 100 tickets available


1 Apr
Early bug tickets sale ends

Standard tickets on sale


1 May
Call for papers ends


15 May
Agenda announced

Call for volunteers ends


8 Aug
Call for sponsors ends


11 Sep
Nominations for Dev of the Year announced

Voting for Dev of the Year starts


21 Sep
Tickets sale ends

Last chance to buy a ticket


30 Sep
DEV: Challenge Accepted 2023

The conference day


Another great conference organized by us


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