An international technical
software development conference

9th September 2022, Sofia Tech Park, Sofia, Bulgaria

About The Event

DEV: Challenge Accepted is a full-day single-track conference for everyone with a strong interest in development. Do not miss the opportunity to join its one and only premiere this autumn! The first conference edition will take place in Sofia Tech Park, as well as online.


John Atanasoff Forum
Sofia Tech Park
Sofia, Bulgaria


September 9th 2022
Day 252 of Year 2022

The event is over.

DEV: Challenge Accepted 2023 will be held on September 30th in Sofia Tech Park.
Tickets sale and call for papers coming in the beginning of 2023.

Event Schedule


Come. Register. Drink coffee. Meet other creatures like you from the very early morning.

Hello, world!

An official opening of the conference.

An opening keynote

by Bozhidar Bozhanov - Bulgarian Minister of E-Government

Bozhidar Bozhanov

Bozhidar Bozhanov is the Minister of e-Government in the cabinet elected by the 47th National Assembly. Besides that, he is an IT expert, entrepreneur, and information security promoter. He is a graduate of Goldsmiths, University of London, and has significant experience in e-government development; as an expert; and has crucial involvement in many amendments to laws and strategy papers. Bozhidar Bozhanov has been a speaker at numerous conferences and is one of the most popular bloggers and influencers in the technical field. He is one of the top users in Stack Overflow, and his tech blog is considered one of the most successful blogs for Java developers by international online media.

Coffee break

Did you know that the Netherlands were said to consume the most coffee per capita with a whopping 8.3 kilograms?

Beyond the for-loop

by Ilian Iliev - Software Engineer @ Lifesum

Ok, so you have learned the basics of programming: data types, flow control; now what? We often see smart people who have just learned to write code or have some experience but are still unsure how to move further or become more appealing to the job market. Here we will talk about tech and soft skills that are vital to you as a future developer.

Ilian Iliev

Ilian Iliev, Ph.D. has been programming since 2003 and in love with Python since 2009. He loves Python for its simplicity to use, power and flexibility. Nowadays, he works as a software engineer at Lifesum, a digital health company based in Stockholm, Sweden. He loves sharing knowledge and helping people improve their skills and finds this especially valuable to novice programmers who are still struggling to pick good practices or find their way. To give back to the community, he has presented at multiple events such as Beginner's Day at EuroPython 2016, Workshops at HackConf 2018 & 2019, Talk at HackConf 2021, and many local meetups in Sofia and Stockholm. Outside the tech world, Ilian loves the sea, snorkeling, fishing, and traveling with his family.

The Process of Creating Decentralised Apps

by Ognyan Chikov - Senior Blockchain Developer @ LimeChain/LimeAcademy

A decentralized application (dApp) is a distributed open source software application that runs on a peer-to-peer (P2P) blockchain network rather than on a single computer. Ognyan will tell us more about dApp, the process of creating one, how it works, and the benefits.

Ognyan Chikov

Ognyan Chikov is a Senior Blockchain Developer in LimeChain, with 10+ years of experience in Computer Science. Starting his career as a CISCO-certified network engineer, he joined the company in 2017 as its first employee. Now he is Team Leader for different blockchain projects, such as Bridges, DEXes, Liquidity Minings as a Service, Blockchain Ethereum development and deployment frameworks, innovations, and Zero-Knowledge Proofs concepts. And currently, besides being a blockchain developer, he's also a mentor at LimeAcademy. His favorite languages and tools are Etherlime - Ethereum development and deployment framework (written by him), Javascript, Hardhat, Typescript, Angular, React, and Vue. Outside work, he is an IoT master and has many side projects connected with smart homes.

Coffee break

Did you know that drinking coffee was once punishable by death? During the 17th century Ottoman Empire, it was believed that coffee contained mind-altering effects. The ruler of this period believed it to be a type of narcotic and banned it from public consumption.

Vital aspects of a product data lifecycle

by Desislava Andreeva and Victor Gueorguiev - Members of technical staff @ VMware Bulgaria

Data analysis has become an integral part of every company's decision flow. Therefore, it is of utmost importance for software engineers to be data literate and understand the product data lifecycle. That is why we are bringing a data engineer and a data scientist to our stage, each of them providing their point of view of the critical issues while working with product data through it‘s lifecycle. Desislava and Victor will highlight aspects of the product data lifecycle from origin through the collection, transformation, loading, and analysis, focusing on essential topics of data governance such as data security, retention, quality checks, and tests. They will uncover what makes an efficient data project regarding execution and team collaboration and some critical issues in these areas trying to attribute responsibility and decision making and deriving advice on tackling them in a production environment.

Desislava Andreeva

Desislava has been working as a software engineer for more than 6 years. She started her career working as an embedded developer with C. Still, over a year ago, she became involved in cybersecurity and analytics by joining the Security analytics team of VMware Carbon Black Bulgaria. Desi is passionate about sharing her knowledge and experience, and she has presented in online events, such as Women Who Code and ISTA conference in 2021. Outside work, she enjoys exercising, cooking, and pampering her two cats.

Victor Gueorguiev

Victor is a data scientist working in security analytics at VMware Carbon Black. He began his career as a data scientist to explore and to grow his passion for leveraging data and analytics to solve complex business problems. Victor enjoys discovering areas where machine learning can be applied to improve the user experience and overall functionality of a product or service and to share knowledge with his peers and the community. Outside work, he is a passionate hobby photographer, hiker, runner, and piano player.

Lunch sponsored by

"When people you greatly admire appear to be thinking deep thoughts, they probably are thinking about lunch."
~ Douglas Adams

A keynote

by Harry Roberts - An independent Consultant Web Performance Engineer

Harry Roberts

Harry helps some of the world’s largest and most respected organisations find and fix their site-speed issues. He is both a Google- and a Cloudinary Media- Developer Expert, and has consulted for clients from the United Nations to the BBC, General Electric to the Financial Times, and a whole host more. When not doing client work, he writes, teaches, and speaks about the entire gamut of front-end performance. When not doing work at all, he’s probably out on his bike.

Coffee break

Did you know that scientists are turning the oil from waste ground coffee into biodiesel, so one day coffee may be fuelling your car?

Will Luke Skywalker consider using autopilot while driving on the Earth?

by Pavel Kanazirev - Software Expert @ Bosch Engineering Center Sofia

The use of vehicles will change fundamentally in the future as a result of automated driving. The autonomous system needs to sense the environment, determine the exact position on the road, and decide how the vehicle should behave in a given situation. How important is the perception as part of the decision-making algorithm, which are the devices used lately, and how important and reliable is the radar? Pavel will glimpse these topics and explain how we verify and validate the product and the tools used.

Pavel Kanazirev

Pavel Kanazirev has 18+ years of experience in software development and 11+ years of experience in the automotive industry. He worked in Germany, Spain, and Bulgaria on various projects related to server applications for the Internet and Intranet, programming perception applications for mobile devices. In his professional career, he has taken multiple roles in different projects (QA, software developer, system engineer, function owner, software architect, system architect, etc.). He also volunteers in multiple educational initiatives: Foundation “Minu Balkanski”, Junior Achievement, Teach for Bulgaria, Professional Association of Robotics and Automation, Yambol Robotics Club, etc.

Suffering from Success

by Nedelcho Nikolov - Team Lead @ Enetpulse

Imagine a monolith cloud application going from 50 to 100 000 and more visitors in a minute? At Enetpulse, Ned had to deal with a fast-paced environment where every second matters. That is why he will tell us about his experience with high and inconsistent traffic to their products, what they did to handle it, what worked, what didn't, and what technologies helped him and his company.

Nedelcho Nikolov

Nedelcho has been a software developer for 12+ years. He graduated in Computer Science from the Technical University of Gabrovo and got an additional major as Project Manager at New Bulgarian University. His greatest passion is working with new technologies and improving the existing code base according to the best practices and the latest trends. Ned's hobbies are coding, learning new things, training and games. Nedelcho always had a passion for sharing his knowledge with other people. He has volunteered at the Challenge Accepted conferences, so he decided to debut as a conference speaker on our stage.

Beer break

Did you know that the Slavic word ‘beer’ (‘pivo’) came from the verb ‘to drink’? Initially, in these lands, anything drinkable was called ‘beer’.

Why should you care about "empowered teams"?

by Hristo Zahariev - Head of Product @ Software Group

How many times have you been a part of a project with a growing scope, short deadlines, challenging requirements, demanding clients and management? We all need work-life balance, satisfaction from delivered work, and the right to feel motivated when we leave that daily stand-up at 9.15 am, don't we? Hristo will share a proven solution to the challenges above that enables the product dev teams to be autonomous, impactful, and find meaningfulness in what they are doing. Simply put, Hristo will tell us the steps to turning your team into an empowered team.

Hristo Zahariev

Hristo is the Head of Product at Software Group, аn end-to-end digitalization partner of financial institutions globally, where he leads a dozen product managers responsible for a portfolio of more than 7 product lines. Before that, Hristo was working at Experian, a leader in the space of information services on credit data. In the past 10+ years, he has been a part of creating, managing, and introducing leading and innovative solutions recognized by companies like Forrester, Gartner and Celent. His passion is to engage and inspire more young people to pursue a career in product management.

Scale up, screw up. Why do we fail when we grow?

by Dawid Pacia - Engineering Manager @ Docplanner

A company started (rapidly) scaling up, and things suddenly collapsed? People, products, projects, processes, or any other area can hugely influence the company's condition. During the last 10+ years working for start-ups, Dawid had a chance to observe, participate and suffer many issues and challenges. With the final conference talk for the day, Dawid will take us on tour showing how to detect (which sometimes is close to impossible), prevent, and (hopefully) fix them on time!

Dawid Pacia

Dawid comes from Krakow (Poland), and describes himself as 1/3 QA, 1/3 Python, 1/3 Lead - a tech freak following all the newest technologies (and implementing them on his own). Fan of the Agile approach to project management and products. Dawid is actively speaking and traveling worldwide (combining both passions). He is an organizer and originator of the first regular Ukrainian QA meetup, “UkrainQA”, and a big cat lover.

Beer break

Did you know that the builders of the Great Pyramids in Egypt were paid in beer?

Lightning Talks

A lightning talk is a short presentation lasting up to 5 minutes. If you would like to talk on any topic that might be interesting for the rest of the community, we invite you to sign up on the conference day and share your thoughts from our stage.

Closing Ceremony

Time for an entertainment show, some raffle prizes from our sponsors, and the finale grande!

Afterparty Preparation

We need just a couple of minutes to rearrange the hall...


Time to grab a drink and continue the interesting discussions during the day, make new friends, and have fun!


That's all, folks! Commit and push.


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

29 Apr
Event is officially announced

Call for papers opened.
Super early bug tickets on sale
Only 100 tickets available.


17 May
Super early bug tickets sale ends

Early bug tickets on sale
Only 100 tickets available


24 Jun
Early bug tickets sale ends

Standard bug tickets on sale


1 Jul
Call for papers ends


18 Jul
Agenda announced


1 Aug
Call for volunteers ends

Call for sponsors ends


1 Sep
Onsite tickets sale ends

Last chance to buy an onsite ticket


7 Sep
Online ticket sale ends

Last chance to buy an online ticket


9 Sep
DEV: Challenge Accepted

The conference day


Another great conference organized by us


Gold Sponsors:

Silver Sponsors:

Bronze Sponsors:


Sofia Tech Park
IT Weekend - Тренировъчен лагер за IT специалисти - най-голямата ИТ общност в България
ITEventZ - Твоят гид в света на ИТ събитията
Noob 2 Junior
Women Who Code
Coding Girls Sofia
Women Techmakers – портретна, модна, продуктова фотография
Kiwi TCMS - the leading open source test case management system
ERP Academy
PromoBG Shop
Ora - Task management done right!
Coffee And Book
Diplomat Plaza Hotel & Resort
Devin - Mind Your Body
Sofia Karting Ring