At O3, we specialize in optimizing every touchpoint along your customer's journey, leveraging strategy and design, technology and innovation to drive digital transformation.
We’re seeking a highly skilled Senior Kotlin Backend Developer (Contractor) to help design and build scalable, secure, and cloud-native backend systems. You’ll be working directly with our client in this role. This role is ideal for someone with strong Kotlin, Java/Spring Boot skills, experience in distributed systems, and practical AWS experience. You’ll work closely with DevOps, frontend, and product teams to deliver enterprise-grade solutions.
Responsibilities:
- Design and develop high-performance backend services and APIs using Kotlin and Spring Boot
- Build and optimize microservices in a distributed, cloud-native architecture
- Leverage AWS managed services (EC2, RDS, Lambda, S3, DynamoDB, etc.)
- Deploy applications via Docker, Kubernetes, or ECS
- Collaborate on infrastructure automation using Terraform or CloudFormation
- Contribute to CI/CD pipelines and application security best practices
- Participate in architectural discussions, code reviews, and team mentorship
- Drive performance tuning and help evolve the tech stack
Requirements:
- Must have 5+ years of professional Kotlin/Java development experience
- Strong Spring Boot expertise
- Hands-on AWS experience (no certification required)
- Proficiency in microservices, Docker, and orchestration with Kubernetes or ECS
- Experience with both SQL (MySQL/PostgreSQL) and NoSQL (DynamoDB, MongoDB)
- Familiarity with AWS networking/security (IAM, VPCs, subnets) – a strong plus
- Knowledge of IaC tools like Terraform or CloudFormation – a plus
- Experience with Maven/Gradle and CI/CD (GitHub Actions, Jenkins, etc.)
- Bachelor’s degree in Computer Science or related field
- Excellent problem-solving and collaboration skills
Nice to Have:
- Experience in highly regulated or enterprise environments
- Familiarity with monitoring tools (CloudWatch, Prometheus)
- Exposure to event-driven systems (Kafka, SQS/SNS)
Who we are:
- We are strategic consultants that align with our client’s to drive CX and innovation.
- We’re great collaborators and take pride in our ability to manage and serve our clients at each touchpoint.
- We are approachable and want to work with our partners to have a shared understanding of their business and provide valuable insight to drive change within their organizations.
- We show up for our clients ready and willing to put in the work to deliver on their beha
Our values:
- We apply optimism by sharing our enthusiasm, positivity and good nature one person at a time.
- We trust in people and treat others with openness and respect.
- We commit to the communities we serve by focusing on values and culture alignment that promotes diversity, equity and inclusion both inside and outside our company.
- We embrace iteration and believe in a world where opportunity for continuous improvement requires a strong sense of flexibility and willingness to grow.
- We focus on the future for ourselves and our clients, pushing boundaries and staying on the cutting edge.At O3, we hire those who share our values, believe in our culture, and are driven to succeed. We’re here to create meaningful experiences and long-lasting relationships, and none of that is possible without a diverse team and an inclusive environment where you can do your best work.
Feel like your past experience doesn't align perfectly with every qualification in our job description? We encourage you to apply anyway! At O3, we are dedicated to building a workplace environment that is diverse, inclusive, authentic and equitable. We know that studies have shown women and BIPOC are less likely to apply to jobs unless they meet every single qualification. So, we welcome you to come as you are regardless of race, color, religion, creed, citizenship, national origin, age, sex, gender, pregnancy, gender identity/expression, sexual orientation, marital status, disability (including neurodiversity), genetic information or veteran status. Our policies aim for the highest standards of fairness and equal opportunity, covering all aspects of employment, including, but not limited to, recruitment and employment, promotions, compensation, team opportunities, and training programs.
We are committed to compliance with all laws and regulations relating to equal employment opportunity, affirmative action, and harassment.
