Senior Software Engineer - DaaS / APIs / MCP

cognism; Poland; On-site; PLN 180,000 - 300,000; Full time

Job summary

Cognism Warsaw Hub is building a leading data-and-services platform. We seek a Senior Software Engineer to design, develop, and operate backend services powering DaaS, APIs and MCP in a cloud-native, scalable environment.

You'll own features end-to-end, collaborate across Product, Architecture and Data teams, and contribute to architectural decisions while ensuring high quality and reliability. Fluency in English is essential.

Qualifications

• 5+ years of professional software engineering experience.
• Experience designing REST APIs and distributed microservices.
• Hands-on knowledge of AWS or another major cloud platform.
• Experience with SQL and NoSQL databases.
• Strong understanding of CI/CD, Git and modern software engineering practices.
• Excellent communication skills and fluent English.

Responsibilities

• Design, build and maintain backend services supporting DaaS, APIs and MCP.
• Deliver production-ready software with strong focus on quality, reliability and performance.
• Own features from technical design through deployment and operational support.
• Collaborate closely with Product Managers, Architects, Platform and Data Engineering teams.
• Contribute to architectural decisions and continuously improve engineering standards.
• Write automated tests and participate in code reviews.
• Use AI-assisted engineering tools to improve development productivity.

Skills

Backend development

REST APIs

Distributed microservices

AWS

SQL/NoSQL

CI/CD

English communication

Java/Scala/Kotlin/C#/TypeScript

Testing & reliability

Tools

Kubernetes

Docker

Kafka

Job description

WHO ARE WE

Cognism is the leading provider of European B2B data and sales intelligence. Ambitious businesses of every size use our platform to discover, connect, and engage with qualified decision-makers faster and close more deals. Headquartered in London with global offices, Cognism's contact data and contextual signals are trusted by thousands of revenue teams to eliminate the guesswork from prospecting.

About Cognism

Cognism is building Europe's leading B2B Sales Intelligence platform. Our engineering organisation is transforming around customer outcomes, data quality and AI-first engineering. The Warsaw Hub is being established as one of Cognism's two primary engineering centres and will play a key role in the company's long-term growth.

About the Role

As a Senior Software Engineer, you will build the services that power Cognism's strategic Data-as-a-Service (DaaS), APIs and Model Context Protocol (MCP) capabilities. You will work on cloud-native distributed systems processing large volumes of business data and exposing it through secure, scalable APIs used by enterprise customers and AI-powered workflows. This role is ideal for engineers who enjoy building high-quality backend systems while owning software throughout its lifecycle.

What You'll Do

• Design, build and maintain backend services supporting DaaS, APIs and MCP
• Deliver production-ready software with strong focus on quality, reliability and performance
• Own features from technical design through deployment and operational support
• Collaborate closely with Product Managers, Architects, Platform and Data Engineering teams
• Contribute to architectural decisions and continuously improve engineering standards
• Write automated tests and participate in code reviews
• Use AI-assisted engineering tools to improve development productivity

What Success Looks Like

• Deliver strategic platform capabilities on time
• Take ownership of production services with measurable reliability improvements
• Contribute reusable engineering patterns adopted by multiple teams
• Act as a trusted technical mentor for less experienced engineers

Required Experience

• 5+ years of professional software engineering experience
• Strong backend development skills using Java, Scala, Kotlin, C# or modern TypeScript/Node.js
• Experience designing REST APIs and distributed microservices
• Hands-on knowledge of AWS or another major cloud platform
• Experience with SQL and NoSQL databases
• Strong understanding of CI/CD, Git and modern software engineering practices
• Excellent communication skills and fluent English

Nice to Have

• Kafka or event-driven architectures
• Kubernetes and Docker
• Infrastructure as Code
• Experience building public APIs or developer platforms
• Experience with AI coding assistants such as Claude Code, GitHub Copilot or Cursor

Why Join Cognism

You will join the founding engineering team of Cognism's Warsaw Hub, helping build a strategic platform that will shape the company's future. You'll work in a modern engineering environment with significant ownership, direct impact on product direction and opportunities to influence architecture, engineering practices and culture from the earliest stages of the hub.

Hiring Process

• Recruiter introduction
• Hiring Manager interview
• Technical coding interview
• System design interview
• Final leadership conversation

WHY COGNISM

At Cognism, we're not just building a company - we're building an inclusive community of brilliant, diverse people who support, challenge, and inspire each other every day. If you're looking for a place where your work truly makes an impact, you're in the right spot!

Our values aren't just words on a page-they guide how we work, how we treat each other, and how we grow together. They shape our culture, drive our success, and ensure that everyone feels valued, heard, and empowered to do their best work.

Here’s what we stand for:

• We Own the Outcome Together.
• We Deeply Understand our Customers.
• We Celebrate Impact Wherever It Comes From.

At Cognism, we are committed to fostering an inclusive, diverse, and supportive workplace. We welcome applications from individuals typically underrepresented in tech.