Merkato is an app in Poland (for Android & iOS) that connects local people who want to sell or buy used stuff on the fly.

Merkato is an app in Poland (for Android & iOS) that connects local people who want to sell or buy used stuff on the fly.






UI Design, 



UX & product strategy,

UI Design, 


From idea to MVP and 10 000 registered users.

The total valuation of products on Merkato’s marketplace exceeded 1 000 000 PLN.

From idea to MVP and 10 000 registered users.

The total valuation of products on Merkato’s

marketplace exceeded 1 000 000 PLN.

From creating MVP to more than 12 500 registered users.

From 0 to total valuation of products on Mercato’s marketplace exceeding 1 000 000 PLN.


The Idea was born.

You’ve probably experienced it before…

It’s quite uncommon for 3 people to come up with the same idea in the same week but that actually happened, and I’m going to tell you the story of how it started.

Few phone calls, few chats, we were pumped! You know how it goes, you probably experienced it before.

You think about an idea and you are really excited about it….you get the dopamine & endorfines flowing in your blood stream when you talk about it with your friends and they share the same vision….coincidence? I don’t think so! 😉

You are waking up the next day and the idea is still there and it still sounds reasonable. Ok, let’s do it!

“With Great Power Comes Great Responsibility…”

– Ben Parker, the Spiderman


Each of us have expertise in our field. The combination of our skills made us self-sufficient and the project sustainable in the long run.

Strategic decisions were made always together and each of us had freedom & their own responsibilities in their own area.

On the high level approach we had the same vision & drive for the project.

Research, do your homework first!

“Give me six hours to chop down a tree and I will spend the first four sharpening the axe”

― Abraham Lincoln

We conducted research to better understand and learn more about the filed. We collected a lot of data – extracted insights and benchmarks. We were taking deep dives into this subject from the angle of each field (business, technology, design)

From the high level perspective, during that stage we found answers for following questions:

  • For whom we are solving the problem? (Target audience)
  • How big is the problem we are trying to solve? (Market)
  • Are there other products that are already solving it? (Competition)
  •  if so… are they solving the problem? (Products)

Many findings from this stage were added to the presentation that was created months later.


Few slides from the presentation

The bird’s-eye view of the solution – the backstory

Personally I’m a sci-fi fan. In the “Eva” (2011) movie, Daniel Brüh is playing a genius which was employed by his former university to design AI for robots. There is a scene when he is at home in his workshop.

He has this really cool tool to design AI. 

Think about it as a Lego bricks visual programming language fully interactive holograms gesture UI.

In an instant he is able to zoom out and see the bird’s eye perspective of his project.

And zoom in to see the smallest tiniest details…

He can see how different systems are working together. Everything is interactive & interconnected. He can change each module, he can play with it the way he likes.

I wrote this long introduction because user story mapping for me is what this design tool is for the main character from the “Eva” movie.

Sure it’s a little different, two-dimensional and not so interactive and high-tech. Instead of holograms there are sticky notes and instead of gesture UI there are pens and pencils 😉 but it’s just a great tool to envision new ideas and explore their dynamics.

PS. If you are working on an interactive hologram version, please contact me right away! I am your perfect early adopter 😉

Clarifying the idea – User story mapping

I always see value in doing user story mapping.

It’s build from the user perspective. Every feature, every interaction is built on top of the user journey.

It helps everybody get on the same page. It fosters discussions and helps to get the same understanding about high level features & every little detail.

It’s great for MVP & Lean development. Based on it you can craft your first release, first version of your idea. It’s a reference during every and each of your next iteration.

It’s great for most projects. Personally I believe it’s useful 90% of the time. It’s a design tool that you can use whether you are creating a new app or planning your 1 month of traveling through Indonesia.

Below you can see the user story map of our app.


All user stories – User story map of our app.

MVP – The way we crafted first release

“If You’re Not Embarrassed By The First Version Of Your Product, You’ve Launched Too Late”

― Reid Hoffman

We distilled the experience down to the core functionality – core value proposition.

If you think about Dave McClure‘s customer lifecycle we were able to get a grasp of the funnel from Acquisition to Retention.

Below you can see the first release.


Our first release – User story mapping 

Releasing something into the world (in the early stage) is always exciting and a little scary at the same time.

However it is the best way to test assumptions and get early feedback.

We got four 1-star reviews on Google Play. Below you can see one of them.


Screenshot of the review from Google Play console

Those four reviews were a little painful but it was something we knew could have happened and it was fair. In MVP version you could add only one photo of your item (no ability to add title, description, category or more photos) so people had to send messages to each other and ask about everything – it’s understandable why they were upset.

There is no such thing as “bad feedback” and to be honest we were kind of happy that somebody cared enough to let us know what’s the most important for them.

Also, we had already prioritize the features that were mentioned in the review to be built in the next releases – those reviews were another thing that confirmed our roadmap.

During the first release we were able to get answers for many questions, here are just a few of them:

  • Cost of acquisition from Facebook & Google Adwords (CPC, CPI, CP added products)
  • Conversion rate on app install from Google Play & App Store
  • Conversion rate on registration in the app (Continue with Facebook)
  • Engagement inside the app (% of active users who visit item, add item, send message)
  • User retention

After the first release, we learned that this idea about the app can actually work.

Each new release – Lean development

“If you can’t measure it, you can’t manage it”

― Peter Drucker

We were crafting each release having in mind the value that we are bringing to our users.

Hypothesis – Assumptions – The way we are going to measure it. Learn – Build – Measure loop.

We weren’t able to conduct an A/B test at that stage but because we were doing it step by step we were able to double check each feature and make data informed decisions.

We were tracking our core KPI’s and with each new release we were adding events to track new features. After a while we started learning from the data we had been collecting.

First few releases were focused on the core functionality, mostly on the basic features with high value for users (add titles, prices, categories, visit other user profile etc) after that we were using RICE method to prioritize each release.

Below you can see what was shipped in the first six sprints.


First six sprints of development

3 pillars of user experience

Based on a research, competitive analysis and our gut, we wanted to focus on those 3 core elements right from the get go:

  1. Flow of adding items for sale
  2. Fostering trust
  3. Product presentation

1st – Flow of adding items for sale

For users – adding products, something that takes a long time on other platforms we wanted to be as fast as taking a photo.

For the platform – it’s the answer to the question “what came first the chicken or the egg” in the case of building a marketplace from scratch.

Also on the Polish market there are many products solving that problem but none of them are mobile only. It’s not only about the platform – it’s about how we believe this problem will be solved 5 years from now.

Win – win.

For users & for the platform.

There was one major insight about adding/posting products for sale online. It was something that came up at interviews and was also seen in the reviews of our competitors online – Posting items for sale is time consuming.

Based on some interviews it takes about 10-40 minutes to post your item/items.

This is how it looks like:

  1. You have to find the item you would like to sell (often it’s at the bottom of your closet)
  2. Sometimes (depending on the item) you have to clean it first to make it look good on photos.
  3. You are ready to go online & create your listing. On most of the services in Poland it’s obligatory to fill in all fields, like: add Title, Description, Category (sometimes there are more things depending on the category) and at least one photo.

So as you can see it’s time consuming.

Also, based on our data 63% of people are adding 2 or more items to sell.


If you have more than 1 item for sale – you have to block even more time from your day to post all those products.

That’s why most of the time selling your unused stuff is tagged in your mind as “I will do it this weekend”. We wanted to change that perception. Eliminate unnecessary steps & brake the flow into small chunks – You don’t have to do it all at once.

Don’t wait for a weekend – it’s so fast you can do it now!

There is a good piece of advice from James Clear “Atomic Habits” book that can be applied here. The author is writing about taking small and incremental steps towards building a habit. He advises “make it easy for yourself” – even though that sounds obvious it’s not used so often. If you want to build the habit of drinking water always after waking up, just put the bottle next to your bed. Boom!….you just hugely increased your conversion to drink water after you open your eyes.

The same goes with adding your products for sale.

The most important step (the one that is moving the needle) should be the easiest one. Just open the app and take a photo. You take the photo & and your listing is live for sale – your chances of selling the product hugely increases.

Want to increase your chances even more?

  • Share it with your friends (you just increased your chances by 20%)
  • Add more photos (15% increase)
  • Add the title & description (10% increase).

All those things can be done later.

The most important step is already made. Your listing is live for sale.

Add listing_02

Easy way to enter the flow

Add an item button. This is the most important action in the app. CTA is highly visible and easily accessible from every main screen in the app.

Number of steps in the flow

The balance between number of added listings & the number of high quality listings (many great photos, well described item) is the most important.

Add listing_wf

Add listing selected screens

Below you can see some of the selected screens from Add listing flow.

(awesome illustrations by icons 8)

Add listing_03

Add listing_06

2nd – Fostering trust between users

2nd – Fostering trust between users

If you think about it, trust has always been and still is the biggest currency in trade.

The most effective way to foster trust from the beginning was to use Facebook as a way to verify users. Facebook is the most popular social media platform in Poland and we were already using it to drive traffic to our app.

Main advantages:

  • Fast and easy registration (Continue with Facebook CTA)
  • Legit users & their profiles (real photos, real names)
  • Possible lower % of spam and abuses from the beginning



Main elements to establish and foster trust:

  • Verified by Facebook sign in Profiles
  • Real names of the sellers and buyers
  • Large photos of sellers and buyers
  • Ability for instant contact

3rd – Product presentation

Right from the beginning we wanted to focus on an advantage that we had because we were creating a mobile platform.  I’m talking about product presentation and the difference between vertical and horizontal listing photos.

All platforms of our competitors in Poland are designed in a way that product is presented horizontally (on the feed & on the listing detail.)

When you think about it, back then in 2006 when they were designing the platforms it made perfect sense – there was only desktop traffic.

On January 9, 2007 the first Iphone was officially announced.

Since then mobile phones became more popular. Therefore mobile apps were created to take advantage of more and more traffic coming from mobile devices – but the framework stayed the same. They were designed having a horizontal photo presentation as a default. Once again it made perfect sense because their main traffic still was coming from desktop.

But the dynamic was changing, one mobile user at the time…Now in 2019 the mobile is huge and there is no going back.

Because we were creating a mobile platform we wanted to use that dynamic to our advantage.

Home screen – difference between horizontal and vertical.



Product detail – difference between horizontal and vertical.

? Contact me anytime

? Contact me anytime

? Contact me anytime

? Contact me anytime

? Contact me anytime

Made with ? in the beautiful city of Krakow © 2019 Mateusz Tatara

Made with ? in the beautiful city of Krakow © 2019 Mateusz Tatara

Made with ? in the beautiful city of Krakow © 2019 Mateusz Tatara

Made with ? in the beautiful city of Krakow © 2019 Mateusz Tatara