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Puzzel • Sofia, Bulgaria

Senior Backend Developer - C# & .NET

Remote-first – once per month in the office

Fully flexible hours

Dog friendly

Apply now

Job Description

Senior Backend Developer - C# & .NET

Sofia, Bulgaria

Puzzel: The Low-Down 🔍

Puzzel is a fast-growing B2B SaaS company. With 25 years’ experience since our foundation in Norway, we’re already #1 in the Nordics, growing rapidly in the UK and expanding into the Netherlands and Finland in 2024, but our ambition is to become the clear European market-leader in the coming years 🚀

We are specialists in customer experience (CX) with a focus on omni-channel customer engagement platform (the category is called ‘CCaaS’ or ‘Contact Centre as a Service’) with the flexibility and scalability to support local enterprises and global corporations, manage their customer interactions and support their busy teams.

We work hard and we play hard, making sure we constantly evolve to stay ahead of the curve. We have an annual kick-off party to celebrate our successes and plan for the year ahead and pride ourselves on being inventive, dependable, adaptive and empowered. We value open communication and honesty to confidently deliver the best service and experience to our customers.

Why we’re proud

  • 2024 CX Awards Winner, ‘Best Mid-Market Contact Center Platform’
  • Puzzel was recognised as the 'most innovative European-founded CCaaS provider' and top 3 globally by Frost & Sullivan in 2023
  • Best Practices Company of the Year 2023
  • Glassdoor rating of 4.5
  • 2023 customer NPS score of 37
  • Puzzel places high importance on work-life balance and flexible working hours - as recognised by Flexa, placing 25th out of all companies they partner with in 2023!
  • We are working with Mercer on salary benchmarking, to ensure pay equality and market competitiveness

Key Data Points

  • €50m revenue in FY 2023 (up from €45m in 2022)
  • Currently ~240 employees
  • Used by more than 1100 businesses across 40 countries
  • Servicing ~60,000 customer service agents on a daily basis + 800 million customer interactions yearly

What you'll do 🏡💻

The Senior Backend Developer will be an integral part of our Self-Service Automation development team, split across Malmö, Sweden and Sofia, Bulgaria (which is where the backend team are mostly based).

The automated chatbot is the start of the majority of customer journeys and with the recent advances in ChatGPT and OpenAI, is technologically at the forefront of what we do. Meanwhile, Digital Engagement helps to guide prospective customers through their buyer journey on the website, which results in increased conversion of sales – inherently beneficial to any business.

Even if you’ve not worked with a directly comparable product, you should of course have an interest in this field and pushing the envelope!

It’s important to mention that this is an individual contributor role with no direct reports, so we're looking for hands on developers.

Key Responsibilities

  • Design, develop, test and document software used in our Puzzel Chatbot & Digital Engagement offerings.
  • Lead technical development projects, with particular focus on backend.
  • Develop, maintain, document and support the software development in C# & T-SQL.
  • Write and document cloud agnostic code in a clear structure, that is easy for others to read and understand.
  • Collaborate closely with colleagues in Bulgaria & Sweden predominantly (and across other Puzzel locations as required).
  • Ensure a very high standard of reliability & stability.
  • Help design and fulfil component roadmaps for the designated product team.
  • System architecture.

The must haves 💪

  • Degree in Engineering, Computer Science or equivalent
  • 5 years development experience
  • Experience with large scale web applications
  • Experience in developing high security web apps
  • Experience/proven knowledge in: C#
  • Experience in .NET Core

The nice to haves ➕➕➕

  • SQL Server or T-SQL
  • Docker containers
  • Kubernetes
  • Azure pipelines
  • Experience of complex integrated systems with several different tech stacks
  • Agile methodology
  • Machine Learning or AI
  • Data security
  • Continuous delivery
  • Git
  • “GenAI” embeddings
  • Elastic search (or similar)

The location

NV Tower, bulevard „Doctor G. M. Dimitrov“, Sofia, Bulgaria

The team typically go in 2-3 days/week, with the rest working from home; the office is there 5 days/week if so desired!

What’s In it for You? 💰

  • Competitive target salary (with a small commission component)
  • Flexible, hybrid approach to working; split your time between the office and home
  • Access to a state-of-the-art office with a partly subsidized sports centre (gym/spa/pool)
  • You get to be part of a fun, driven and supportive team
  • Gift on your birthday
  • Annual Summer and Christmas parties
  • Excellent development opportunities and a great company culture

What to expect from the interview process ❔

  • Screening call with Talent Acquisition
  • 1st interview with the Development Manager + Product Owner
  • 2nd interview with a Lead Developer, local HR + Development Manager
  • Final interview with Development Manager + Director of Development

Puzzel Values 🎯

  • Built on Trust – trust is an intrinsic Nordic value, upon which Puzzel has been built. We trust each other and our customers and partners trust us.
  • Stronger Together – working together in a genuinely collaborative way, with a shared purpose, we have an empowered organisation that is better equipped to delight customers and partners.
  • Stay Hungry – have a continuous hunger to raise our game, innovate and be the best we can be professionally.

Equality and Diversity 🌍

We want everyone at Puzzel to be their true, authentic selves at work irrespective of nationality, race, ethnicity, religion, sexual orientation, gender identity, physical ability, age, or economic background.

Whilst we are proud to already have a diverse workforce from across the globe, we are aware that things could always be improved – for example, we currently have a ratio of female 26:74 male employees, which whilst not uncommon for the tech industry (average in SaaS is 26% female), it’s far from ideal. So, what are we doing to improve this?

  • Our Global Leadership Team (C-suite) has shifted from 100% male to 60 male: 40 female in the past 12 months.
  • We have increased our % of female hires from 23.6% in 2021 to 38.5% in 2023.
  • We are partnering with the likes of Flexa, who have significantly higher-than-average talent pools of candidates from diverse backgrounds.
  • We are working with State Employment initiatives in Norway and Sweden to bring candidates through internship/apprenticeship routes and are investigating similar initiatives in the UK and Bulgaria.
  • By raising awareness and transparency, we are hoping to further attract a diverse workforce.

We are continuously striving to foster an inclusive and diverse environment, where everyone is celebrated for who they are. If there is anything we can do to support you in the interview process, or beyond, please let us know.

One Last Thing ☝🏻

Even if you feel you are only a 75% match for this role, we still want to hear from you. This list is purely indicative. Skills can always be learnt.

Please note that we are not able to provide sponsorship for this role, so you must have eligibility to work in the country you are applying for.

By applying you accept the terms of our Privacy Notice which can be found on our website. Puzzel are not considering candidates that do not have a work permit in the country we are hiring in.

Company benefits

Co-working space allowance
Enhanced WFH tools
Flexible working week
Mental health platform access
Dental coverage
Health insurance
Work from home allowance
Enhanced sick days
Adoption leave
Enhanced sick pay
Compassionate leave
Optional unpaid leave
Enhanced maternity leave
Enhanced paternity leave
Shared parental leave
Life assurance
Salary sacrifice
Matched pension contribution
Annual pay rises
Teambuilding holidays
Lunch and learns
Company wide holidays/offsites
Employee assistance programme
Dog friendly co-working space
Open to part time work for some roles
Employees are very happy with their working location freedom
Employees are very happy with the flexibility in the hours they work
Employees are largely happy with the benefits their company offers
Work-life balance
Employees feel that they can find the perfect balance of life and work
Role modelling
Employees feel that flexible working is part of the culture
Employees feel they have complete autonomy over getting their work done

Additional employee ratings
(these do not contribute to the FlexScore®)

Employees feel that the diversity is good and there are continued efforts to improve it
Employees feel like the company culture is brilliantly inclusive and equitable
Employees feel like it is a really great environment to work in
Employees feel quite excited about the company mission
Employees are very happy with their salaries and feel that it is well above the market average

Working at Puzzel

Company employees


Gender diversity (male:female)


Office locations

London (Bank), Copenhagen, Stockholm, Malmö, Uppsala, Arendal, Oslo (HQ)

Hiring Countries






United Kingdom

Awards & Achievements

Most flexible companies

Most flexible companies

Flexa100 2024
Professional Services

Professional Services

Industry awards 2023

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