Position: Back-end Engineer Python (Experimentation squad)
Company: Preply
Experience required: 5y
English level: upper

We are currently looking for a **Back-end Engineer in Experimentation Squad** to join our Platform tribe.
Here in Preply we a/b test most of our changes on production, both product and technical before scaling it to all customers. Platform tribe owns the whole infrastructure that is used to make those business-vital decisions.

**You, as a part of Experimentation Squad, will:**
- Develop systems that are used by all product and platform squads in their daily work in the decision making process; 
- Tackle problems that occur in highly loaded systems, such as cross-experiment correlation, data consistency, event deduplication, etc.; 
- Design and monitor architecture in a way that will guarantee stability and reliability in the highly variative environment.

We work in small teams, thus you will be able to influence system design and contribute a lot in the company's growth, also we promote self-direction to work on meaningful projects, while we also strive to create an environment that provides the support and mentorship needed to learn and grow.

**Responsibilities:**
- Establish credibility with the quality of the a/b testing system.
- Develop new ways of a/b testing (SEO a/b testing, etc.).
- Own Data pipelines and ensure Data consistency.
- Support & develop a/b testing interpretation tools.
- Integrate with 3rd party providers.
- Collaborate with product teams to help them tackle technical issues with a/b testing.

**What we are looking for:**
- Strong knowledge of Python, at least 2+ years experience.
- SQL hands-on experience.
- Understanding basics of statistical analysis: p-value, null hypothesis, confidence interval - something you should be familiar with.
- A passion for analyzing data to inform decisions.
- Addiction to measuring and monitoring.
- High code-testing standards.
- Readiness to take responsibility of systems that directly impact company decision making process.
- Minimum B2 English level is a must.

**What we offer:**
- An opportunity for personal and professional growth, supported by high functioning teams, stellar investors and the exciting challenges that come with joining a company at the start of its growth trajectory.
- An environment free of bureaucracy and corporate constraints; a culture where your opinion is highly valued and appreciated.
- An open, collaborative, dynamic and international culture.
- A monthly allowance for self-development on Preply.com.
- A competitive financial package, with generous leave allowance and health insurance.