141+ verified reviews. Every one traceable to Upwork, Trustpilot or Google My Business.

Regulated · medical research

"Highly recommend Marek.!"

E-commerce

"I highly recommend working with Marek! He implemented the required tracking in our project quickly and professionally. The entire process went incredibly smoothly, and communication was top-notch."

Services

"Marek was great to work with. He knows his stuff, communicated well and delivered a solid audit with clear advice I can actually use. Professional throughout and overall a really good experience."

Agency

"It was great to work with Marek. He did a lot of complex work that I needed help with and didn't have time to do on my own. Really happy he could get STAPE set up for our conversions."

Regulated · finance

"Excellent - Great experience"

Real Estate

"Marek is professional whit 15 years. experience , advice from marek are like gold to my business"

"Working with Marek was a great experience. In just 30 minutes, we were able to put together a clear plan, and it's already executing very well. His insight and ability to quickly understand the situation made a big difference. I'm looking forward to continuing to work with him in the future."

Regulated · mushroom gummies

"Marek is a great google ads specialist that can get ads through even with more difficult categories. Highly recommend!"

Coach

"After working with a few freelancers on Upwork for tracking and pixel setup without much success, Marek has been my go-to expert. He cleaned up my tracking and did an excellent job. I highly recommend him to anyone who is serious about fixing their tracking and improving their ad account performance!"

Coach

"Marek is super professional and absolutely best in his industry! If you want someone you can trust with mission-critical work, Marek is my #1 recommendation."

E-commerce

"Marek knows Google Ads!"

SaaS

"Mark helped us with some Google Ads issues and feedback for our AI Google Ads application. Communication was clear and professional, and he provided practical recommendations we could implement quickly. Overall, a very knowledgeable specialist in Google Ads and performance marketing."

Regulated · peptides

"Marek is an expert in tracking and ad channel managing. He helped scale our account efficiently and integrated accurate server side tracking. Always available and great communication overall. Don't hesitate to work with him!"

Real Estate

"Marek can do what others meta gurus can not . big help ad clarity"

Real Estate

"Very great and helpful consultation."

Real Estate

"It was a very good consultation session. He helped with our Google and Meta Ads setup."

Services

"Marek really knows his stuff. We have just begun working, but he seems to really understand Google Ads in a way that my previous contractors didn't, or didn't care."

Real Estate

"Marek is very experienced, clear and straight forward. I recommend everyone to get into contact with them." || "Thank you. If you need more help - you can always write me John. Take care!"

"My experience with Marek was excellent. He was very insightful, professional, and easy to talk to, which made the conversation flow smoothly. He genuinely cared about my best interests and took the time to understand how he could best help me. I would highly recommend him to anyone."

Real Estate

"profi - can handle difficult setups like lead scoring from crm meta capi"

Services

"Marek gave us some very good guidance. He is a master of his craft and is very strong in strategy too"

SaaS

"We had a great experience with Marek, he is an extremely senior marketer and was able to provide deep insights and useful feedback!"

Coach

"Fantastic work! Always available, super reliable, and fast. Highly recommended"

E-commerce

"Marek possesses exceptional expertise in his field. As a specialist in data analysis, he collaborates closely with Google. I began my journey with no resources, yet within the first month, I achieved a break-even point. In the second month, we not only generated profits but also expanded our operations, aiming for significant growth. There is no need to seek alternatives; simply exercise patience and place your trust in Marek. You will be pleased to have discovered his talents."

Services

"Very good consultation!"

E-commerce

"Great experience. Delivered amazing result for us"

Regulated · Restricted Industry

"Facebook Ads Guru. Excellent freelancer. Will hire him again."

Regulated · Restricted Industry

"Excellent work from Marek. I'm just terminating this contract to rehire him on an hourly rate."

E-commerce

"The work was very good and on time. Just what we needed"

Services

"Marek was extremely professional, organized, and efficient throughout the project. He quickly identified and resolved a complex tracking issue caused by a poorly executed server-side tracking integration from a previous contractor. His expertise made a big difference, and he handled everything with clarity and precision. I especially appreciate the comprehensive tracking restructuring plan he proposed, it brought real value and helped us see the bigger picture. We will definitely reach out to him again to help execute the plan he designed. I highly recommend working with Marek!"

E-commerce

"Marek really knows his stuff and is a pleasure to work with on Google & Meta Ads campaigns."

Regulated · luxury rehab

"Will hire again, marek has been exceptional and we continue to use him in other businesses"

Regulated · Restricted Industry

"I can't say enough good things about Marek's work and professional approach to a challenging contract. His Facebook Ads insight are the best you will find on Upwork or anywhere. We will keep him as a contractor in the future."

Agency

"Was great to work with Marek. I'll work with him again for new jobs."

E-commerce

"Working with Marek was an amazing experience. He went above and beyond the job scope, demonstrating incredible responsibility and reliability. He's the kind of person who talks less and lets his work speak for itself. Much respect to him!"

Lead Gen

"Our project involved setting up conversion tracking in Google Tag Manager for Google Ads, with Marek also recommending we implement Facebook Pixel tracking simultaneously - good suggestion. Marek completed the work quickly and on schedule, but what I appreciated most was his responsiveness in answering my questions, following up, and ensuring everything was double-checked. He really knows his stuff. Highly recommend"

Regulated · finance

"Marek is great to work with. He helped to optimize our ads and formulate a better strategy. I would recommend others hire him as well."

Regulated · peptides

"An expert in conversion tracking and attribution. Rebuilt our entire tracking set up for G Ads and Meta for better attribution."

E-commerce

"He is professional, gives trust and he has patience. I will work with him again."

E-commerce

"Marek is a great guy, pleasure to work with!"

Regulated · peptides

"Marek audited a serverside tracking setup from another freelancer I hired here and he found some critical issues immediately; the previous set up ended up being a waste of money. I'm very happy I found Marek; very thorough and knowledgeable, and provided a full report of what needed to be fixed. Will be hiring him again for more work."

E-commerce

"Marek delivered exactly what was needed within the agreed timeframe and was incredibly helpful in setting us up for success beyond this contract. Will work with him again in future!"

Regulated · cbd gummies

"Extremely knowledgeable and thorough, Marek is one of the best!"

E-commerce

"Absolute expert. Needed someone who spoke the language of attribution and making sure Google analytics, Google tag manager , meta and good ads were all communicating and tracking correctly. Got lucky hiring Marek on my first attempt."

E-commerce

"Great understanding of Facebook ads. Marek was able to setup an advanced dynamic catalog and strategy for us that is working to improve our Facebook ad ROAS. Experienced paid ads consultant that I will be working with again."

Regulated · psychologist therapist

"Fast work that did the job perfectly, where others failed miserably. A breeze to work with Marek."

SaaS

"If you're looking for someone to fix your GTM issues or configure a tracking from scratch, look no further as this is the most experienced guy in the field i've worked with. Professional and respectful guy that will keep his end of the deal. Have been working with him for over 2 years, and never failed in fixing any issue surfaced. A+ GMT/ Analytics/ Tracking and Ads guy! Highly recommended for anyone looking for such expert."

Regulated · psychologist therapist

"Hired him before and going to hire him right after this. Everything worked like a charm and quickly too."

Regulated · psychologist therapist

"Marek helped us to fix some issues on a difficult setup. Het kept going when it wouldn't work in the first place. I am currently working with him on another project too, so I think that says everything."

Coach

"I've had the pleasure of working with Marek on several occasions to enhance our tracking capabilities, focusing on platforms like Google Ads, Analytics, GTM, and Facebook Ads. Each time, Marek has consistently delivered outstanding results. His profound knowledge and expertise have directly led to an improvement in our ad performance and ROI. For anyone in need of elevating and improving their online tracking, I can't recommend Marek enough. He's genuinely the real deal!"

E-commerce

"Marek was a pleasure to work with on resolving issues with my Google Merchant Account. He was quick, efficient, and took the time to explain the changes he made and why. I will work with him again!"

E-commerce

"Marek is very professional and extremely knowledgeable in his field. He has been a great help and I recommend working with him!"

E-commerce

"Wonderful working with Marek. He's very smart, talented, and responsive!"

E-commerce

"Working with Marek is easy, he has a deep understanding of the google ads. Our website ads managing is not the simplest to say. But with scripts we were able to scale our ad spent. The communication, and the viability is almost instant, so when you need a quick fix or a budget optimization, or a new campaign he is here to help."

E-commerce

"Marek is an exceptionally talented professional with a distinctive and commendable work ethic. His expertise and approach truly set him apart."

E-commerce

"A great specialist in the field of analytics, especially when it comes to Shopify. I recommend to everyone."

E-commerce

"I highly recommend collaborating with Marek."

E-commerce

"Marek did a great job and gave us many insights. His experience is showed in the work and his assignments are completed very quickly. We did a tracking setup and marketing channels audit which gave us an overview of things we can improve on and the direction in which we should focus. Probably not the last time we will work together."

E-commerce

"I had the pleasure of working with Marek, a freelancer who assisted me with configuring GA4 and GTM analytics. Marek demonstrated a high level of professionalism and an extensive knowledge of integration. He provided excellent guidance and advice throughout the project, which was greatly appreciated. Overall, I would highly recommend Marek to anyone in need of his expertise in this field."

Agency

"Marek is great and gets everything and more done when we call on him for a job."

Regulated · ecommerce

"Overall great to work with and knowledgeable."

Coach

"Would highly recommend Markek to anyone who wants great quality work done. Marek did an exellenct job cleaing up our tracking and our data, improving our overall system. I've worked with other developers before, but unfortunately their work was not complete. So Marek really did save us and would definitely recommend to just go with him from the start! Will definitely hire again! Thank you Marek! :)"

"Highly recommend. Outstanding communication, professionalism and extremely helpful attitude. Problem-solver! Was a pleasure to work with Marek, would hire again."

"Extremely skilled and did what we needed him to do"

"extremely skilled currently we are downsizing our business so we are lowering our spend and making sure we save as much as possible"

E-commerce

"Marek is a great expert with huge knowledge. I recommend him to everyone with data problems."

"Marek's consultation was very valuable. He clearly knows his subject mater very well. What I appreciated even more than his expertise though, is that he was able to customize his recommendations to my unique situation and stage of business development and explain his reasoning with data and examples. Highly recommend!"

E-commerce

"Great job - responsive and finiched on time!"

Agency

"Marek really knows his stuff. He is an expert. I will definitely work with him again if I need his expertise."

Agency

"Excellent work and very knowledgeable about the fast changing components of google, online advertising and how to ensure correct data collection from visitors."

E-commerce

"Marek is a super contractor. Very professional with great communication. His skills are astounding, he went above and beyond the task."

E-commerce

"Marek is a very good specialist in the field of google analytics. He completed the order efficiently and at a high level. Fluent communication even on weekends."

E-commerce

"Marek is the best Google Analytics specialist with whom I have had the pleasure to work so far. He performed his tasks comprehensively and at the highest possible level. I highly recommend it to anyone who runs any kind of e-commerce."

E-commerce

"Marek is a pro, he did a thorough audit of our tracking and GA setup, and left us with clear instructions on what and how to do next. Very knowledgable and friendly in all interactions. 10/10!"

Agency

"Very knowledgeable about google tags and Facebook tracking. Highly recommended."

E-commerce

"Marek is always amazing to work with. Handles all our issues and concerns with every project, and is very knowledgable. Highly recommend!"

E-commerce

"Exceptional experience"

E-commerce

"Marek is great, he knows digital advertising inside and out and I would work with him again. He's responsive and meets deadlines. Thank you Marek!"

Agency

"I will work with Marek again. He made recommendations and improvements beyond what I had asked for because he knew what needed to be done in order to accomplish the ultimate goals I had for the project. I'd recommend his service to anyone."

E-commerce

"Marek is incredibly knowledgeable about tracking, and fixed this issue no problem for us. He is very reliable and communicates clearly with a great sense of humour. Our Australian team really appreciates having Marek available to help whenever we have an issue."

E-commerce

"Marek is incredibly intelligent and efficient. He set up server side tracking for our 3 Shopify websites, and integrated Facebook Ads, Google Ads and Analytics. He worked long hours to get this finiched for us before Black Friday sales, and communicated his progress clearly throughout, through messages, videos and Zoom calls. He has also done extensive testing for us after he finiched the contract, to make sure everything is running smoothly. I wouldn't hesitate to recommend Marek to anyone who needs a digital advertising tracking expert."

Agency

"Good communication and GETS RESULTS! He helped us figure out issues with Google Tag Manager. Would hire again."

E-commerce

"Marek was incredible to work with, truthfully. He really know's his paid advertising & tracking in the digital space. Highly recommend for anyone needing help or assistance in this field. Very well rounded!"

Regulated · medical research

"Would always recommend working with Marek!"

Regulated · psychologist therapist

"Marek can solve problems my (expensive) facebook advertising agency cannot."

E-commerce

"Marek did an excellent job with understanding our needs and goals with our campaigns. He is very knowledgable and this shows with the various strategies he applies throughout the campaigns. Highly recommended!!"

E-commerce

"Marek is an expert in both Google and Facebook ads. Very detailed with his work and a lot more advanced than what you would typically see. He was able to structure our Google ads well and get them going with a steady return. Definitely recommended!"

E-commerce

"Great support by Marek to implement our Pinterest tag using Google Tag Manager! Many thanks Marek"

Regulated · medical research

"Marek is an expert at what he does. Would highly recommend."

E-commerce

"If you want to get the job done, you need to hire Marek. He has knowledge that goes beyond just setting up and optimizing ads. He provides great insight and has a great strategic mindset. I would hire him again 100%."

E-commerce

"Marek is very qualified with setting up Google SEO as well as Facebook Business Manager he can also work within Shopify. I would not hesitate hiring Marek for any work you need done and will rehire again if needed"

Regulated · ecommerce lingerie sexy

"Marek is brilliant and has really helped our business grow and expand to other channels. He's very very talented and knowledgable I highly recommend him 10/10"

E-commerce

"Marek was incredibly knowledgeable and confident setting up advanced ecommerce tracking for our company's multiple Shopify stores. He did the work when he said he would, and was happy to explain and troubleshoot things after the job. He sent lots of screen recording videos so that I could clearly see what was being done and why, which I appreciated."

E-commerce

"Marek is a true pro with Google Adwords and Facebook, especially the technical implementation and tracking. I highly recommend him for even your biggest puzzles."

Regulated · psychologist therapist

"Second time working with Marek, went really well."

Regulated · psychologist therapist

"Very fast worker. Did quality work. On the ball."

Lead Gen

"Marek completed an audit of our website and google ad campaigns. The report provided was very comprehensive with a effective plan to improve our online marketing. Was recommended to us and will be using him again."

E-commerce

"Super helpful. It was a pleasure working with him. He is knowledgeable about the subject and teaches well too! I already re-hired him for another contract."

E-commerce

"Marek has been great to work with, very patient and responsive I look forward to working with him again soon."

Agency

"He is very knowledgable in tracking conversion issues....colour me impressed! Marek's ability to troubleshoot and explain his resolution has been so valuable."

Regulated · ecommerce lingerie sexy

"Marek is great to work with! Extremely knowledgable and very communicative and finiched the project very quickly! Super impressed and would highly recommend."

E-commerce

"Marek is very knowledgeable and explains everything he does in great detail. If you want to get the job done and learn something Marek is your guy!"

Regulated · ecommerce

"It was great working with Marek, he was very quick and very knowledgeable."

Regulated · ecommerce lingerie sexy

"Marek was excellent to work with! Very communicative and got the job done quickly. He's clearly incredibly knowledgable about marketing and and analytics and was able to help me with very little direction. I highly recommend him and will be working with him again in a few weeks to further improve our marketing, tracking and analytical set up. Thank you again!"

E-commerce

"Marek did an outstanding job setting up my google and bing shopping accounts, he has a great understanding of both platforms, and also setting up needed tracking codes in my shopify store. He communicates in a timely manner via email and video with updates and instructions, he also answered all my questions and understood that I was a small business and was very thoughtful about staying within my budget for this project. I would not hesitate hiring Marek again and you will be very satisfied hiring Marek for any project you have. I will also be hiring with him again for other projects I have in the near future."

E-commerce

"Loved working with Marek, as per usual. Great knowledge."

E-commerce

"Fantastic help with google ads."

E-commerce

"Fantastic help with google optimization, etc."

E-commerce

"FANTASTIC HELP WITH GOOGLE!"

E-commerce

"Amazing knowledge and help with google ads."

E-commerce

"Amazing knowledge of google ads."

Lead Gen

"Marek is a great professional who knows his stuff and constantly learns and introduces new techniques to improve tracking of our ads. For example, he literary helped us track Facebook users with adblocker turned on. He has a massive Google Ads and Facebook Ads background which helps - as he instantly knew where the problems with tracking were. He found those problems and eliminated it without problems. He has massive knowledge about all kinds of Ecommerce tracking including google tools (Google Ads, Google Analytics, Google Tag Manager, Data Studio etc.) Facebook tools (like Attribution, Business Manager, Analytics, Pixel, Offset and Line of Business) and Pinterest stuff - and if he doesn't know system (which was the case with TikTok) he can learn on the job in like 15 minutes of reading documentation. It's always a massive pleasure working with him. 100% recommend. :)"

E-commerce

"Marek is very knowledgable with google ads."

E-commerce

"Always love working with Marek!"

E-commerce

"Knows a lot about consulting and google ads. Taught me quite a bit of information."

E-commerce

"Marek went above and beyond in completing my task. He actually recorded video footage showing me how to adjust certain adjustments he made to my Shopify. Very talented at coding. I will be using Marek again."

"Marek is extremely knowledge and helped us figure out the issue in one call. What I liked about him is his honestly and how he helped us figure out our issue by avoiding over-spending on useless solutions. Will work with him again for sure!"

"Marek pointed out in one call everything that could be related to our tracking problems. Now we have better knowledge and can try different things to fix it. Will hire him again in the future."

"Marek is a 'guru' of Googe Ads and my go-to-guy for resolving any complex problems with setup and configurations for Google Ads account and its campaigns. My marketing team wasn't aware of configuring server side setup so I was referred to Marek by my friend with high praise and Marek lived up to all the positive things I had heard about him. He is undoubtedly a subject matter expert (SME) in this area of Google Ads. I will rehire Marek for any complex issues I face in future - he's prompt, responsive, affordable and goes out of the way to deliver extra."

"Marek is a highly talented analytics expert who can examine organization data at multiple layers, identify issues, and fix them."

"Marek is hands down the best tracking expert I have ever worked with! He not only resolved all of my tracking issues but also flawlessly handled the tracking needs of all my clients. His expertise and attention to detail are unparalleled. Marek's ability to quickly diagnose and fix complex problems is truly impressive, and his clear communication throughout the process made everything smooth and stress-free. If you're looking for a top-notch tracking professional, Marek is your guy. I couldn't be more satisfied with his work and highly recommend him to anyone in need of tracking solutions!"

"I highly recommend Marek to anyone who's looking for a high-level approach to solving data analytics problems and overall measurement of data to allow for intelligent business decisions."

"Marek deserves a 5* rating in all aspects. He knows GTM and tracking for both FB and G Ads thoroughly and can implement changes swiftly and efficiently. He is prompt in providing support and guidance. He is always willing to troubleshoot and debug issues. We look forward to working with him."

"Useful consultation, clearly what I needed"

"Marek is truly an expert when it comes to Tracking and Google Ads. His PPC knowledge is high level. He keeps on top of the latest trends and has the patience and persistence to implement those in accounts that he managed. He is prompt in responding, quick with his analysis and takes the time to really understand the business. I was very impressed with his initial account review as it was extremely detailed and highlighted quite a few changes that have the potential of increasing the account performance by 30-40%. Marek is a good human being who will empathise with your business challenges and will go out of the way to find a suitable solution. He is a pleasure to work with. I highly recommend him."

"We hired Marek twice and of course we are going to make sure he gets all the great feedback whenever possible! Marek goes above and beyond! We are so happy with his work on our Ads campaign and will continue to work with Marek whenever possible! You are missing out if you do not hire him to help you with your campaign. Thank you for all your help Marek!!"

"This feedback is long overdue. Marek goes above and beyond! We are so happy with his work on our Ads campaign and will continue to work with Marek whenever possible! You are missing out if you do not hire him to help you with your campaign. Thank you for all your help Marek!"

"Fantastic Work! 0 Complaints whatsoever. Would thoroughly recommend Marek. He is extremely skilful and deep insights into tracking, which was exactly what we were looking for !"

"Marek is the one of the best on Upwork."

"Very good job. Marek is a very good Google Ads expert. Very professional. I highly recommend it."

"Marek was a huge help!"

"Marek created our google ads campaigns from scratch using historical data. It was done at an amazing speed. After a week the new setup is already outperforming the old one and we are looking optimistically into the future thanks to Marek. I can't recommend him enough"

"Markek explained everything I needed clearly and efficiently. Got a lot done in a short amount of time. Now my funnels are set up and i can improve my ecom conversions. If you need help with your Google analytics and want some expert level guidance and help, hire Marek."

"Marek knows what he is doing when it comes to tracking. He set up server side tracking with facebook capi and tiktok api on both my websites. One of the websites was multilingual and multicurrency. I can highly recommend him 5/5"

"I have nothing but great things to say about Marek. He knows his craft, is very efficient and I've found him very pleasant and easy to work with. He's completed everything we asked within time and budget, and I will surely work with him again in the future for anything related to user tracking. 10/10."

"Marek did all i wanted plus added some extra ideas."

"Marek is extremely knowledgeable with online advertising. We had a lot of questions and he walked us through everything step by step. We look forward to hiring Marek for future projects!"

"Fast and great communication! Truly an expert and look forward to working with him again!"

"Very good experience with Marek. Extremely skilled and communicates well. Would definitely work with him more often in the future."

"Marek did a fantastic job and got it done quicker then our agreed timeline. Will be using him again."

"Great work and very helpful"