Jiří Antoňů

Partner at Tessero | helping event organizers save costs & support the community | entrepreneur & engineer

LinkedIn Profile | me@jiriantonu.cz | jiri@anto.nu | jirka@nullable.group | jiri.antonu@tessero.cz

Current Ventures

Tessero

Partner

Full-time | Aug 2023 - Present | Prague, Czechia

At Tessero, we work with small- and medium-sized event organizers to optimize their operations so they can run stress-free events. Even event managers deserve a good night’s sleep!

With Tessero, our organizers:

As partner and managing director, I lead our sales and customer success efforts, ensuring that every organizer gets the best possible experience. Under my leadership, Tessero has:


nullable group

Partner

Full-time | Oct 2020 - Present | Prague, Czechia

At nullable group, we work as technology consultants, developing custom IT and tech solutions for companies of all sizes. Our clients include major corporations like DELOITTE, NEXT CLINICS, and UNILEVER, as well as fast-growing startups such as Creative Dreamers.

Through our work, we:

As partner and managing director, I oversee sales, customer success, and a team of engineers, ensuring that every solution meets our clients' needs. Under my leadership, nullable group:

I also act as the official representative of nullable group in the general assembly of CZ.NIC, of which nullable group is a member.

Previous Experience

Punktum dk

Software Engineer

Part-time | Apr 2025 - Feb 2026 | Copenhagen, Capital Region of Denmark, Denmark

Punktum dk is the Danish national domain registry and a key part of the nation's critical digital infrastructure, responsible for ensuring the reliability and resilience of national domain services.

As a Software Engineer, I contributed to the core backend systems that power this essential infrastructure. My work helped maintain a system of high integrity and availability.

This role provided invaluable experience in developing software where system integrity and performance are paramount to national digital connectivity.


DTU - Technical University of Denmark

Assisting Teacher

Part-time | Sep 2024 - Jun 2025 | Copenhagen

Mathematics 1a and 1b are the cornerstones of DTU’s polytechnical foundation, a mandatory and rigorous sequence designed to equip every engineering student with the analytical tools necessary for their degree.

I was selected as the only second-year undergraduate student to serve as a Teaching Assistant for these courses — a role traditionally reserved for graduate students. Working closely with professors at DTU Compute, the Department of Applied Mathematics and Computer Science, I:

This role sharpened my ability to communicate complex technical concepts with clarity and precision, while managing the high-stakes responsibilities of evaluating student performance within a large-scale academic environment.


AdPlenty - Local Marketing software

Software Engineer

Part-time | Sep 2023 - Mar 2025 | Copenhagen, Capital Region, Denmark

AdPlenty, a fast-growing Danish startup, with over 10 million DKK in ARR, that received the Børsen Gazelle award during my time there. As the second engineer employee there, I contributed to the development of complex platforms that streamline multi-location franchise marketing.

My work included:

This role allowed me to work on high-scale automation challenges and refine my expertise in building scalable and efficient SaaS solutions, while diving deep into the Danish startup ecosystem.


CZ.NIC, z.s.p.o.

Software Engineer

Full-time | May 2023 - Aug 2023 | Prague, Czechia

CZ.NIC, the administrator of the .cz top-level domain and the operator of MojeID and other government identity and domain systems. As a Software Engineer there, I contributed to the development of critical digital infrastructure.

My work included:

This role allowed me to work on high-impact systems that support both public and private sector services, deepening my expertise in secure digital identity and domain management.


Česká televize

Software Engineer

Full-time | Jul 2019 - May 2021 | Prague, Czechia

At Česká televize, I was part of a dynamic team responsible for developing and maintaining the ČT24 and ČT Sport websites—two of the most visited and trusted news and sports sites in the country, visited by over 1.7 million users every month.

My work also involved:

This experience allowed me to grow in both front-end and back-end development, while playing a key role in enhancing ČT’s digital presence and live broadcasting features.


Seznam.cz

Programmer

Internship | Jun 2019 - Jul 2019 | Prague, Czechia

As an intern programmer at Seznam.cz, the largest Czech IT company operating the country's most widely used search engine, email hosting, maps, and more, I had the opportunity to contribute to key projects in a fast-paced environment.

My work included:

This experience allowed me to gain hands-on expertise in search technologies and large-scale application development while working alongside experienced engineers.

Education

DTU - Technical University of Denmark

Bachelor of Science - BSc., General Engineering with specialization in Cyber Systems

Aug 2023 – Jun 2026

Grade: GPA: 11.5 on scale 12 to -3


EPFL

Bachelor of Science - BSc., Computer Science

Feb 2026 – Jul 2026


University of Sydney

Bachelor of Science - BSc., Computer Software Engineering

Jul 2025 – Dec 2025