Android Engineer (Experiments for Conversion Optimisation)

15000 - 23000 PLN gross / month
Kraków, Poland
Mobile | Android
Work in office

Locations: Poland, Spain


Brainly is the largest social learning community with 350+ Million users monthly. We facilitate peer to peer homework assistance with a variety of products for students and parents. The purpose of our Conversion Optimization team is to de-risk business decisions, learn, and solve customer problems using experiments as our main tool. Becoming the best is then a function of how fast we learn and innovate. 

Instead of arguments around a table we let the users decide. But how exactly? It's simple, we use the golden standard of causal inference, we run tons of fun AB tests.


With Brainly's incredible traffic volume, the statistics are on our side to really trust our experiments — again we're talking about 350 Million active users! 

How do we work:

  • We believe in teamwork, self-organization and adaptation
  • We check our hypotheses with A/B tests and let data tell a story not HiPPOs — Highest Paid Person’s Opinion
  • We are free to explore and use new technologies in our projects — Break things fast to learn even faster
  • We deliver fast and often — Currently avg. of 1 app update per week 

Our stack that you will be working with and learning from:

  • Java and Kotlin code
  • Firebase analytics and experiments framework
  • Multi-module Gradle project
  • RxJava / Dagger 2
  • Rest / GraphQL / WebSocket backend

That said, we are currently looking for a skilled Android Engineer to help us in this growth adventure 🚀 What will you do in this role: 

  • Actively designing, developing, and giving inputs to testing variants to validate hypotheses for Brainly mobile platforms to enhance the learning experience for our users.
  • Solving complex challenges such as performance, scalability, and security
  • Collaborating with other software engineers to design scalable services, plan feature roll-out, and ensure high reliability and performance of your deliverables.
  • Conducting code reviews, contributing high-quality documentation, and building robust test suites for your features.

What you need to be successful in this role: 

  • At least 3-4 years of professional experience in Android
  • Knowledge of Android Framework (lifecycle, good practices, tools)
  • Experience with RxJava, Dagger2 and Android Architecture Components
  • Experience in Unit/UI testing 
  • Firebase AB testing frameworks (Remote Config, Notifications)
  • Experience with Firebase custom events and mobile analytics
  • Understanding of how experimentation cycles work, from hypothesis to analysis
  • Computer science fundamentals - data structures and design patterns
  • Solid knowledge of SOLID principles
  • Communication skills to get things done with Data Analysts, UX researchers, Designers and QA Eng. — Healthy experiments are a team effort and we understand that
  • Attention to detail from a QA standpoint — TBVBP (trust but verify before production)
  • Fluency in English

Nice to have:

  • Experience with Kotlin 
  • Experience crafting testing hypothesis
  • Experience with monetization testing 💰
  • Experience in working on projects with large user-base — We're at 350M monthly users at this point, that's a playground for testing
  • Eagerness to create beautiful, snappy and modern UI


Additional details:

  • Location: Kraków or Barcelona, or remotely from Poland/Spain
  • Start date: as soon as possible (however, we’re happy to wait for the right person)
  • Salary: 15 000 - 23 000 PLN gross/monthly (employment contract)
  • Some of our benefits - the final offer will depend on the location: 
    • Flexible working hours and the possibility to work remotely
    • Personal development budget 800$ per year +  unlimited time off policy for participation in conferences and workshops and access to an online learning platform with courses from Udemy, Harvard Manage Mentor and many others
    • Fully paid private health care packages for you and your family (dental care included) provided by Luxmed
    • Fully paid life insurance provided by Warta
    • Multisport Plus card
    • Access to the Mental Health Helpline - providing virtual support of external psychologists, psychotherapists, and coaches
    • AskHenry services - personal concierge services to help you to settle your everyday matters (like Ikea shopping or shoemaker visit)
    • Possibility to join one of our Employee Resource Groups and initiatives (Inclusion Council, Ladies at Brainly, Brainly Cares)
    • If needed, additional budget for work remote work accessories



Brainly is the world's largest peer-to-peer learning community for students, parents and teachers. At, and its group of websites around the world, students connect to both receive and offer help with homework problems and questions. The unique opportunity for students to freely ask questions and gain the confidence that comes from helping others and inspires students to learn in a collaborative community that receives more than 350 million users each month.

Based in Kraków, Poland, with its US headquarters in New York City, Brainly is currently available in 35 countries. The total funding from current investors, including Naspers, General Catalyst Partners, Point Nine Capital, Runa Capital and Learn Capital equals $150M. More information about Brainly is available on

By sending us your application, you agree that Brainly sp. z o.o. with its seats in Krakow, will process your data contained in the form below and in the documents you attach in to participate in recruitment. In connection with this, you have the right to withdraw your consents, the right to access to your data, the right to obtain their copy, rectify them, erase, limit their usage and also data portability right and object to their use by Brainly, as well as to lodge a complaint with the President of the UODO. If you have any questions regarding the use of information about you and exercising your rights related to this use, please contact our DPO - [email protected]. If you want get to know more about how Brainly uses and process your personal data [click here].