Principal/Senior Backend Engineer

Company Description

Are you ready to take on a high-impact role in building cutting-edge advertising technology? We are looking for a Principal/Senior Backend Engineer to join our team and design a high-load, low-latency real-time bidding platform. This position is based in Warsaw, Poland, with the flexibility to work remotely.
At Sigma Software, we deliver innovative, scalable solutions that empower industries and drive measurable results. You will work alongside talented professionals in a culture that values expertise, collaboration, and continuous growth.
Why join us? We offer competitive benefits, flexible working arrangements, and opportunities to work on challenging projects that push the boundaries of technology.
CUSTOMER
Our customer is a globally recognized technology-driven company operating in the digital advertising space. They specialize in delivering scalable, high-performance solutions that empower advertisers to optimize campaigns in real time. With a strong culture of innovation and excellence, they are committed to building platforms that shape the future of programmatic advertising.
PROJECT
The project is a strategic self-service advertising solution designed to make streaming inventory more accessible, measurable, and performance-driven for advertisers of all sizes. It includes a real-time bidding and optimization platform capable of handling high-load, low-latency auction mechanics. The system integrates forecastin

Job Description

Design and implement core backend services for real-time bidding, optimization, and ad delivery workflows
Build custom bidding agents for real-time bid decisioning
Develop high-load, low-latency components supporting real-time auction and delivery mechanics
Implement proprietary pacing, bid-shading, and optimization logic to improve campaign efficiency
Design and integrate forecasting capabilities for impressions, reach, outcomes estimation, and campaign planning
Work with OpenRTB, JSON, protobuf, and other ad-tech protocols and data formats
Integrate with data and metrics pipelines to support real-time optimization and reporting
Implement observability, monitoring, and troubleshooting capabilities (LGTM/ELK stack)
Collaborate with product, engineering, data, and ad operations stakeholders to deliver scalable performance advertising capabilities

Qualifications

5+ years of relevant experience as a Backend Engineer in commercial projects
Strong backend engineering experience with C++ or Golang
Experience designing and building high-load, low-latency distributed systems
Hands-on experience with JSON-based integrations, protobuf, or similar protocols
Experience with low-latency data stores and caching technologies (Aerospike, Redis, ElastiCache, etc.)
Experience with PostgreSQL or similar relational databases
Proven track record of building production-grade services with strong reliability, scalability, and observability requirements
Ability to work independently, reason through complex system trade-offs, and contribute to architecture decisions
Upper-Intermediate English level
WILL BE A PLUS
Understanding of real-time bidding systems, auction mechanics, and ad-tech domain
Knowledge of pacing, bid optimization, forecasting, or performance advertising delivery mechanics
Experience working on DSP, SSP, ad exchange, ad server, or performance marketing platforms
Familiarity with LGTM/ELK or similar observability stacks

Additional Information

PERSONAL PROFILE
Analytical mindset with strong problem-solving skills
Ability to work in fast-paced environments
Excellent communication skills for cross-team collaboration
Self-motivated and proactive approach to work
Strong attention to detail and commitment to quality