About Us

What is Work On Your Business All About?


Work On Your Business is all about supporting business owners who face operational challenges. Most of our clients are seeking assistance to overcome technological issues, increase focus and productivity, and overcome challenges of a fast-growing business.


We enable you to:

  • Focus and work on the right topics that really move you forward
  • Overcome overwhelm and increase productivity and creativity
  • Find reliable partners that benefit your business’ growth
  • Grow your businesses fast and strategically

In short: Have more time to focus on essential business activities and eliminate anything that does not support your business growth.

We Save Your Time

We don’t just talk about it – we get it done!

Hands-on, no fluff, results-focussed!

  • No matter if you need a team or automations, we work with people AND technology, but make it understandable and convenient for you.
  • We don’t accept mediocriticy but find the best solution for your specific needs. Even if this requires going the extra mile.
  • We will deal with vendors and tech support so you don’t have to. Dealing with provider problems can be a painful waste of time but we are able to resolve issues efficiently.
  • We see business in its entirety and make sure that everything works together so that your business functions as a whole and works for you!

You are best at what you do – we cover everything else for you.

About Us Founders of Work On Your Business

Work On Your Business was founded by Mona Tenjo and Hajo Sonntag to help business owners, self-employed freelancers and entrepreneurs to work ON their business instead of IN it.

“It is our goal is to help entrepreneurs build sustainable and profitable businesses that support the desired lifestyle of our clients!” – Hajo Sonntag

This is not about us, this is all about you and your results.

Find Out What We Can Do For You or
Contact Us To Discuss Your Specific Needs!

Values on About Us

Our Mission & Values

At Work On Your Business, it is our mission to help entrepreneurs work ON their business and not IN it. We help our clients to regain their freedom, keep their focus on the right topics and thrive in business.

Our core values are RESPECT, EXCELLENCE and RELIABILITY. We stand for: Do it once – Have it forever! And adjust when necessary. Because you don’t pay for the time invested, you pay for results! And that’s what we deliver: RESULTS!


Respect is our number one value in everything we do. We respect your time, we will treat your business and your expenses as if it was ours and always meet as equals.


We don’t accept mediocrity. As engineers and strategic consultants, we always strive for building sustainable, functioning solutions that are tested and meet your needs. Our clients deserve nothing but the best – and we will go the extra mile to make that happen.


As original Germans, we love solid foundations and we take words literally. Our word is our bond. We won’t leave you standing in the rain when obstacles come along. We stick with you and work it out. You can count on us!

Meet The Founders

Mona Tenjo Profil Picture

Mona Tenjo

Mona gathered more than 15 years of experience in the areas of accounting, purchasing, business management, project management and even pre-sales. Her strong work-ethics allowed her to climb the career ladder and gain insights on various levels within companies of different sizes.

Mona’s strong track record led her to consult some of the largest organizations, such as Siemens, DP DHL, and HeidelbergCement, and lead the implementation of complex global projects.

Her degree in International Business was extended by countless client projects over the years, that equipped Mona with a profound knowledge of how to make the best out of any business, how to add value to any organization or endeavour, and how to create championship teams. She accomplished to train experts of more than 45 different nationalities in over 15 countries around the world, from half of Europe to Indonesia, Russia, Tanzania, USA and others.

Today she serves our Work On Your Business clients with practical best-practice insights, her ability of breaking complex matters down and by spreading our message to the world.

Hajo Sonntag Profil Picture

Hajo Sonntag

Hajo honed his skills in the technical world of engineering, research and development, and project management at automotive giants like Volkswagen, BMW, Faraday Future and even the Fraunhofer Research Institute.

His technical hands-on education and Master of Engineering degree trained his natural talent of troubleshooting the origins of problems and developing solutions to solve them once and for all.

Being responsible to manage large projects such as developing and launching an entire car and coordinating thousands of people across the globe to work together to achieve a common goal, sharpened his focus on the overall picture for project and company, as well as providing an immense knowledge-base of technical and business strategies and know-how to being able to solve any problem. Additionally, his martial arts career formed and strengthened his character, taught him discipline, leadership, and the value of strategic foresight.

Today, he finds himself as technical and business consultant, partner in media and jewelry businesses, and even mentor.

Hajo Sonntag Profil Picture

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If you want to discuss a specific issue that you face, evaluate your development potential or find out more about us, then get in touch with us.

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