S

Jr Back End Engineer

Sensor Tower
Full-time
On-site
Lisbon

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About this role:


Are you excited about building products that work with real-world, large-scale data?


At Sensor Tower, we process tens of terabytes of data to power insights used by thousands of customers. We’re looking for curious, motivated early-career engineers who want to grow their skills while helping us build fast, reliable systems that make data easy to access and understand.


You’ll work closely with experienced engineers, contribute to meaningful features from day one, and learn how large-scale systems are designed, built, and optimized in production.


If you enjoy learning, solving problems, and shipping real software that users rely on, we would love to meet you. We have a strong track record of leveling up talented juniors quickly, and this role offers a rare opportunity to pair closely with senior leadership.



Our Engineering Culture


We believe that "Simplicity is a prerequisite for reliability." We are looking for engineers who align with our core values:


- Simplicity: We avoid over-engineering. We prefer the tools we already have and the most straightforward solutions over "shiny new toys."

- Quality: We write code that is a pleasure to read because we know code is written once but read many times. We don't cut corners, and we polish to a high level before shipping.

- Extreme Ownership: We don't just do the minimum. We expect you to understand the "why" behind your work and own the ultimate goal of fixing problems at their root cause, avoiding temporary band-aids.

- Prioritization: We focus relentlessly on what is important, not just what is urgent.


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What You Will Work On
  • As a junior engineer, you’ll be supported by mentors and teammates while you:
  • Contribute to features across the full development lifecycle.
  • Help build APIs and backend services that power customer-facing products.
  • Learn how to work with large datasets and high-performance databases.
  • Improve code quality through testing, refactoring, and code reviews.
  • Pair-program and collaborate with teammates to solve problems together.
  • Gradually take on more ownership as you grow.


What We’re Looking For
  • You don’t need to know everything on day one. We value potential, curiosity, and a strong foundation.
  • Preferred: Knowledge of Ruby on Rails and the broader Ruby ecosystem is a large plus. Alternatively, demonstrated proficiency in Python or similar languages, with a willingness to cross-train in Ruby, is acceptable.
  • Nice-to-have: Experience with Clickhouse or other OLAP databases; MongoDB or other document stores; Sidekiq or other asynchronous task runners.
  • Technical Foundation: A strong grasp of algorithms, RESTful systems, and API design. Experience with data analysis and data pipelining is ideal.
  • Github/Portfolio: A portfolio of meaningful Github contributions, open-source work, or interesting personal projects that demonstrate you can build working software.
  • Curiosity & Drive: A proactive approach to digging into sources yourself rather than relying on second-hand information, and an eagerness to understand why a project is valuable before you start coding.
  • Interest in backend systems and working with data.
  • Eagerness to learn and ask questions.
  • Strong communication and collaboration skills


What You'll Get
  • Mentorship from senior engineers.
  • Real ownership of features (not just small tasks).
  • Exposure to large-scale production systems.
  • Collaborative culture.
  • Opportunities to grow and learn new things.


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Read more about some of our Technical challenges here (written by members of our engineering team):


https://sensortower.com/blog/speeding-up-the-backend-with-graph-theory


https://sensortower.com/blog/how-we-scaled-to-thousands-of-sidekiq-workers