Senior Backend Engineer

Qumra Capital; Warszawa; On-site; PLN 180,000 - 300,000; Full time

Job summary

AppsFlyer is seeking an experienced full-stack developer to join the Management team. You will own end-to-end development of products from front-end to back-end and collaborate with cross-functional teams to deliver high-impact features.

You will work in a fast-moving AI environment, designing scalable systems and maintaining code quality with modern practices and tooling. English proficiency and a CS degree are essential for success.

Qualifications

• 5+ years of software development experience with strong backend engineering skills.

Responsibilities

• End-to-end development of AppsFlyer products and features, from front-end to back-end.
• Collaborate with Product Designers, Product Managers and Software Engineers to deliver amazing products.
• Build & ship features at high pace in a fast-moving AI development environment.
• Design, develop, and maintain scalable backend and frontend systems.
• Develop complex applications using modern Full Stack technologies.
• Work with microservices, event-driven architectures, and distributed systems.
• Continuously learn and evaluate new technologies to improve our products.
• Contribute to a strong engineering culture of ownership, collaboration, quality, and continuous improvement

Skills

React

TypeScript

Frontend engineering

Backend engineering

System design

CI/CD

Observability

Mentoring

AI tooling

English proficiency

Education

B.Sc. in Computer Science

Tools

Node.js

GraphQL

Neo4j

PostgreSQL

Redis

AWS

GCP

Kafka

Job description

AppsFlyer is the market leader in the mobile attribution business. We provide analytical tools to help thousands of app developers and agencies reach decisions about where, when, and how to market their apps.

We do this by consuming enormous amounts of data and presenting it in useful (and cool!) ways that are actionable and provide real and immediate value to our customers.

We are looking for an experienced full-stack developer to join our Management team. The Management team manages a variety of services and tools, external and internal. Our missions include diverse business cases, a wide range of APIs, implementation of third-party services, and collaboration with multiple other teams in the company.
Our team uses technologies and frameworks such as (buzzword alert): Node.js, React, Go, AWS, GCP, Kafka, Neo4j, GraphQL, Protobuf, Redis, PostgreSQL, among others.

The Management team is part of the SaasLab group which owns the SaaS platform and control plane of AppsFlyer - the foundational layer that manages users, accounts, billing, API gateway, authentication, permissions, and business integrations. SaasLab’s systems serve as the backbone for every product and feature at AppsFlyer, handling millions of API calls daily and supporting thousands of enterprise customers worldwid

What You'll Do

• End-to-end development of AppsFlyer products and features, from front-end to back-end
• Collaborate with Product Designers, Product Managers and Software Engineers to deliver amazing products
• Build & ship features at high pace in a fast-moving AI development environment
• Design, develop, and maintain scalable backend and frontend systems.
• Develop complex applications using modern Full Stack technologies.
• Work with microservices, event-driven architectures, and distributed systems.
• Continuously learn and evaluate new technologies in the everlasting effort to perfect our products
• Contribute to a strong engineering culture of ownership, collaboration, quality, and continuous improvement

What You Have

• 5+ years of software development experience, with strong backend engineering skills
• Proven track record owning end-to-end solutions with minimal supervision, from ambiguous problem to production
• Strong frontend and backend engineering skills, with deep expertise in React, TypeScript, and modern web development practices
• Solid system design and architecture skills, able to reason about trade-offs across a system's moving parts, not just the code you touch
• Comfortable with ambiguity and lower-clarity problems, able to balance moving fast with doing it right
• Deep experience with modern development practices (unit and integration testing, CI/CD pipelines, code quality, observability)
• Highly product-oriented, you think beyond "just code" and understand how customers actually use what you build
• Experience mentoring other engineers and setting a technical bar through code review and example
• Experience using AI tools within the software development lifecycle, including the ability to review, validate, and improve AI-generated code
• Proficiency in written and verbal English
• B.Sc. in Computer Science or equivalent practical experience

Bonus Points

• Experience with SaaS platform systems — identity, access management, billing, multi-tenancy, API gateways, or similar control-plane domains
• Experience working on core entity systems, identity/account management, or SaaS onboarding flows
• Experience with Node.js, GraphQL, or graph databases (Neo4j)
• Experience with platform/infrastructure teams that serve internal engineering customers
• Experience in the ad-tech ecosystem, preferably with hyper-scale systems
• Recommended by an AppsFlyer employee

As a global company operating from 25 offices across 19 countries, we reflect the human mosaic of the diverse and multicultural world in which we live. We ensure equal opportunities for all of our employees and promote the recruitment of diverse talents to our global teams without consideration of race, gender, culture, or sexual orientation. We value and encourage curiosity, diversity, and innovation from all our employees, customers, and partners.

"As a Customer Obsessed company, we must first be Employee Obsessed. We need to make sure that we provide the team with the tools and resources they need to go All-In." Oren Kaniel, CEO