
Reaktor · Helsinki
Reaktor's tech community is looking for an experienced Senior Fullstack Developer to join one of our Business Units in Helsinki. If you are comfortable working...
Reaktor's tech community is looking for an experienced Senior Fullstack Developer to join one of our Business Units in Helsinki.
If you are comfortable working across modern web applications, backend services and production systems, enjoy solving ambiguous
problems with clients, and are curious to work in a low-hierarchy environment, you might just be what we’re looking for.
You will support clients across a range of digital product, platform and service domains. The exact client context may vary from
focused product teams to large international companies working on high-traffic, business-critical services.
Many of our clients are technically mature and expect a high level of expertise from our consultants. This means you will need to
be hands-on, pragmatic and comfortable helping both the client and the team make good technical decisions.
analytics, online stores, integrations, developer tooling or SDKs
technologies
We do not have a hard requirement around years of experience, but we have noticed that this level of fullstack, client-facing and
production ownership usually takes several years of professional experience to build.
martech or similar product domains
Willingness to work in a hybrid setup. This means balancing office, client premises and remote work depending on the client
project and team needs.
As a Senior Fullstack Engineer in Team Autopsy, you will build automation and optimization capabilities that help our customers save time, improve campaign performance, and reduce the manual work required to manage advertising campaigns at scale. Team Autopsy owns several core services at the heart of the Smartly platform, including Triggers, Ad Rotation, Smartly Actions, and Action Router. These systems enable customers to automate campaign management, optimize advertising performance, and reliably execute changes across multiple media platforms. As an independent fullstack team operating in the middle of the Smartly product ecosystem, we work closely with product managers, designers, and engineering teams across the company to deliver scalable solutions that create customer value. Our technology stack includes TypeScript, Node.js, NestJS, Koa, PostgreSQL, Redis, Kubernetes, and React. We are a data-heavy team and rely extensively on strong typing and shared TypeScript definitions that support development across Smartly. WHAT YOU WILL DO * Design, build, and maintain backend services and frontend applications that power campaign automation and optimization features. * Contribute to technical and architectural decisions that improve scalability, reliability, and developer experience. * Develop and evolve services such as Triggers, Ad Rotation, Smartly Actions, and Action Router. * Collaborate with product managers, designers, and engineers across teams to deliver solutions that address customer needs. * Own projects from planning through implementation, balancing short-term requirements with long-term maintainability. * Improve system quality through automated testing, monitoring, and continuous improvement of engineering practices. * Mentor engineers through code reviews, knowledge sharing, and technical collaboration. * Help shape Smartly’s target architecture by contributing to cross-team initiatives and platform improvements. WHAT WE ARE LOOKING FOR * Strong experience building backend services with TypeScript and Node.js. * Experience developing modern React applications using TypeScript. * Solid understanding of distributed systems, APIs, microservice architectures, and cloud-native development practices. * Experience writing and maintaining unit, integration, and end-to-end tests using tools such as Jest. * Ability to independently drive projects from problem definition through delivery. * Strong communication and collaboration skills, with experience working across multiple teams and functions. * A mindset focused on customer value, pragmatic problem solving, and continuous improvement. * Interest in mentoring and supporting the growth of other engineers. * Ability and willingness to work from our Helsinki office three days per week. WHAT WE OFFER YOU At Smartly, we offer a place where you can advance your career. Here, you'll find: An Inclusive Global Culture: Join a team of over 750 Smartlies, representing more than 60 nationalities across 24 locations in 13 countries. We cultivate a culture built on trust, transparency, and open feedback, where diverse perspectives are valued and encouraged. Global Impact: Contribute to a company making a global impact, directly influencing our customers' success and business growth. Focus on Wellbeing: We prioritize your health with healthcare packages, mental health services, and a commitment to work-life balance through paid holidays and family leave. Comprehensive Rewards: Benefit from equity options, performance-based rewards, competitive compensation, and career development opportunities. Flexible Hybrid Workplace: Experience a hybrid work model, balancing office collaboration with remote work, and the option to work abroad for up to 30 days annually. Apply Now and Build Your Future with Smartly! Curious what it’s like to work at Smartly? Visit our Careers page to see how we grow, collaborate, and make impact together. #LI-HYBRID ABOUT SMARTLY Smartly is the AI-powered advertising technology company transforming ad experiences for brands and their consumers. Our comprehensive advertising platform seamlessly integrates the capabilities of media, creative, and intelligence to power more than 800 billion impressions and generate more than 300 billion creatives annually, delivering tangible business outcomes for brands and advertisers. Smartly is the only company in the industry recognized as a Leader in The Forrester Wave: Creative Advertising Technologies with PwC validating the results it delivers for brands. We manage creative and media for 700+ brands worldwide and $6B in ad spend across the largest media platforms, including Facebook, Google, Instagram, Pinterest, Snap, and TikTok. Our end-to-end technology, unmatched access to media platforms and exceptional customer service help Fortune 500 brands to reach and engage consumers and learn what performs best.Smartly is a multinational and diverse team of 750+ Smartlies from 60+ nationalities, working in 13 countries. Together, we want to create and maintain an inclusive environment where everyone feels respected and heard. Our Diversity, Equity & Inclusion approach is at the heart of it. Visit Smartly to learn more. The processing of your information is described in our Candidate Privacy Notice.
Meta Workspaces is a core product area at Smartly, helping advertisers manage, automate, and scale campaigns on Meta through Smartly. The team builds customer-facing experiences, automation capabilities, and integrations with the Meta Marketing API, enabling customers to access platform capabilities efficiently and operate at scale. As a Senior Software Engineer, you will help design and evolve systems that power high-volume advertising workflows used by customers around the world. You will work across the full stack, own significant technical initiatives, and help shape the architecture of reliable, high-performance systems. You will collaborate closely with product managers, designers, and engineers to deliver features that directly impact how customers manage and automate their advertising operations. WHAT YOU WILL DO * Design, build, and maintain backend services and full-stack product capabilities at the core of Smartly’s Meta Workspaces. * Build and maintain integrations with the Meta Marketing API, enabling customers to access new platform capabilities and manage advertising workflows through Smartly. * Develop and operate systems that process high volumes of advertising operations and data while maintaining strong reliability, performance, and scalability characteristics. * Own high-impact features from product discovery and API design through implementation, testing, rollout, and iteration. * Collaborate with product, design, infrastructure, data, and engineering teams to turn business needs into reliable technical solutions. * Improve the scalability, reliability, performance, and observability of services operating under real production load. * Design robust APIs, service boundaries, and integrations that support complex automation and workflow-driven products. * Explore practical ways to use AI-enabled tools to improve engineering workflows, developer productivity, and the quality of team delivery. * Mentor other engineers and help raise the bar for testing, monitoring, code quality, and operational excellence. WHAT WE ARE LOOKING FOR * Strong experience building and shipping production software as a backend or full-stack engineer. * Professional experience with TypeScript and Node.js. * Practical experience with relational databases, APIs, cloud infrastructure, and distributed systems. * Experience designing, operating, and scaling production services with demanding reliability, performance, and availability requirements. * Ability to make thoughtful technical decisions in ambiguous situations and balance quality, speed, and long-term maintainability. * Experience collaborating across functions and contributing to technical discussions that shape product and engineering outcomes. * Strong written and verbal communication skills in English. * Curiosity about emerging AI capabilities and willingness to explore opportunities to improve products, workflows, and developer productivity through AI. * Ability to work effectively in a hybrid setup, including three days per week in our Helsinki office. Relevant technologies for this team include TypeScript, Node.js, PostgreSQL, React, Playwright, Jotai, Kafka, BullMQ, Kubernetes, distributed tracing and observability tooling, and modern testing frameworks. We don’t expect experience with every technology listed, but we value engineers who enjoy learning new technologies and working across different parts of the stack. WHAT WE OFFER YOU At Smartly, we offer a place where you can advance your career. Here, you'll find: An Inclusive Global Culture: Join a team of over 750 Smartlies, representing more than 60 nationalities across 24 locations in 13 countries. We cultivate a culture built on trust, transparency, and open feedback, where diverse perspectives are valued and encouraged. Global Impact: Contribute to a company making a global impact, directly influencing our customers' success and business growth. Focus on Wellbeing: We prioritize your health with healthcare packages, mental health services, and a commitment to work-life balance through paid holidays and family leave. Comprehensive Rewards: Benefit from equity options, performance-based rewards, competitive compensation, and career development opportunities. Flexible Hybrid Workplace: Experience a hybrid work model, balancing office collaboration with remote work, and the option to work abroad for up to 30 days annually. Apply Now and Build Your Future with Smartly! Curious what it’s like to work at Smartly? Visit our Careers page to see how we grow, collaborate, and make impact together. #LI-HYBRID ABOUT SMARTLY Smartly is the AI-powered advertising technology company transforming ad experiences for brands and their consumers. Our comprehensive advertising platform seamlessly integrates the capabilities of media, creative, and intelligence to power more than 800 billion impressions and generate more than 300 billion creatives annually, delivering tangible business outcomes for brands and advertisers. Smartly is the only company in the industry recognized as a Leader in The Forrester Wave: Creative Advertising Technologies with PwC validating the results it delivers for brands. We manage creative and media for 700+ brands worldwide and $6B in ad spend across the largest media platforms, including Facebook, Google, Instagram, Pinterest, Snap, and TikTok. Our end-to-end technology, unmatched access to media platforms and exceptional customer service help Fortune 500 brands to reach and engage consumers and learn what performs best.Smartly is a multinational and diverse team of 750+ Smartlies from 60+ nationalities, working in 13 countries. Together, we want to create and maintain an inclusive environment where everyone feels respected and heard. Our Diversity, Equity & Inclusion approach is at the heart of it. Visit Smartly to learn more. The processing of your information is described in our Candidate Privacy Notice.
Are you a skilled developer excited to build at the frontier of AI-native software development? We're hiring an experienced developer to shape the future of our AI engine for impact intelligence — full-stack by default, but we care more about analytic skills, good judgment, and AI-fluency than about a specific stack. You'll work across the platform, from data pipelines, APIs, and ML/LLM systems to the product surfaces our customers use, and you'll be expected to pick up whatever the problem requires. At Upright, you get to work on a product that actually matters: the world's largest open-access database on company impact, used by 300+ institutional investors and corporations to make real capital allocation decisions. We quantify companies' impact from the ground up, based on peer-reviewed science and what companies actually produce and sell. The raw material is their product data, which we collect and classify automatically at scale. What makes the role unusual is how we build today. Over the past six months, we have rebuilt a large part of our development workflow around AI agents, including our in-house Slack-native agent "Upbot", which now autonomously handles a meaningful share of bug fixes, feature development, dev-environment management, data QA, data refreshes, and other engineering chores that used to require a human. As a developer at Upright, you spend much less time on repetitive plumbing and much more time designing systems, writing the hard parts, and teaching agents to do the rest well. We're betting heavily on AI-native engineering, and you'd be joining a small, senior team where your work on both the product and the agentic tooling around it is visible from day one. Your specific responsibilities will be tailored during the recruitment process to your background, skill level, and interests. If you're ready to grow your career while building a platform that matters and to do it in an AI-forward engineering environment, we'd love to hear from you!