Hybrid role: 3 days per week at the office in Valencia (Spain)
At
Principal33
we strive to make happiness at work a reality. Because it's not just about the money, it's also about the work environment and appreciation. It's about creating the best team setup you can imagine and getting involved in the things you're passionate about. And you can be a part of it, because it's fun to get things done!
We want our employees to innovate and we allow them to do what they are truly passionate about. Based on this conviction, Principal33 aligns its strategy around its vision: to become a leading IT service company and a better working-life balance. With currently around 200 employees from different countries, we are actively shaping the future of work.
As a
Backend Developer
you will play a key role in building robust, scalable systems that support AI-driven products operating in real time. We are looking for someone who combines strong technical expertise with ownership, system-level thinking, and collaboration.
You will work on an AI-powered video analytics platform focused on
real-time detection and alerting
. The platform processes live video streams and generates alerts when predefined events occur. Your work will ensure that the backend systems are secure, reliable, and ready to scale as the platform grows.
Key Responsibilities
Design, develop, and maintain
backend services in C# (.NET Core)
for the SaaS platform
Design and manage
database schemas and data access layers
using
Entity Framework Core
, ensuring performance and data integrity
Build and maintain
secure, well-documented REST APIs
consumed by frontend and other services
Implement
backend business logic using DDD and Clean Architecture principles
, ensuring clean separation of concerns
Design and operate
microservice-based and event-driven systems
, including
inter-service communication via Apache Kafka
Implement
authentication and authorization (RBAC)
using
ORY Kratos \& ORY Keto
, ensuring secure access control
Support
real-time system behavior and live updates
using
SignalR
where applicable
Collaborate with frontend, AI, and platform teams to design and integrate end-to-end features
Ensure backend systems meet high standards of
scalability, reliability, security, and observability
Write and maintain
unit and integration tests
to ensure system stability and correctness
Participate in architectural decisions and contribute to the
long-term evolution of the backend platform
Requirements
Must-Have Qualifications
Strong professional experience as a
Backend Developer
working with
C# and .NET Core
Proven experience in
database design and data access
using
Entity Framework Core
or equivalent ORMs
Hands-on experience building
secure REST APIs
for production systems
Solid understanding and practical application of
DDD and Clean Architecture
in backend development
Experience implementing
authentication and authorization
, including
role-based access control (RBAC)
Familiarity with
ORY Kratos and ORY Keto
, or similar identity and authorization systems
Experience working with
microservices and inter-service communication
, including
Apache Kafka
Exposure to
real-time systems
and technologies such as
SignalR
Strong experience writing and maintaining
unit and integration tests
Ability to collaborate effectively with cross-functional teams and communicate technical concepts clearly
Nice-to-Have
Experience working in
event-driven architectures
and distributed systems
Exposure to
Python services
within a heterogeneous backend ecosystem (REST APIs, Kafka-based communication)
Experience supporting
AI-driven, data-intensive, or video analytics platforms
Background in SaaS products operating in
high-availability or mission-critical environments
What we offer
Benefits
Flexible work hours
Private medical insurance
Day off on your birthday
Referral bonus if you bring your contacts
Gifts for special occasions
Office that takes care of your well-being and on top of all we are pet friendly, bring your pet to the office!
Fridge full of snacks at the office, healthy ones and not so healthy as well
International and multicultural environment
(Self)-Development
Continuous training, we will help you improve your technical skills, evolve in the tech community and develop as a professional.
We are an active part of the tech-community. You may have the opportunity to attend and participate in local and international tech-events.
Wanna join!?