Senior Backend / API Platform Engineer

Location: Japan

Type: Contract / Full-Time (depending on engagement)

About Virtasant

Virtasant is a global technology services company that delivers outcomes through automation. Our services include software engineering, technology operations, cloud migration, application modernization, and cloud optimization.

We help some of the world’s largest organizations modernize their technology operations, optimize costs, and unlock new opportunities for innovation. Our fully remote, globally distributed team is passionate about delivering world-class technology solutions while embracing a culture of excellence, ownership, and impact.

About the Role

Our client is building scalable, secure data infrastructure and programmable APIs to power next-generation advertising and marketing platforms.

They operate complex datasets including advertiser information, campaign performance, and media placement data. This data underpins critical business processes—from campaign planning to reporting and strategic decision-making.

This role sits at the core of that platform.

You’ll design and build APIs, data pipelines, and infrastructure that enable reliable, secure, and scalable access to high-value data across the organisation.

What You’ll Be Doing

• Design, build, and operate high-performance APIs using Go

• Develop and manage data pipelines using Apache Airflow

• Build and maintain data storage and processing infrastructure

• Design and implement monitoring and observability systems

• Deploy and manage infrastructure across AWS and/or GCP

• Collaborate with stakeholders to define and refine data and API requirements

• Contribute to architectural decisions across microservices and data systems

• Ensure systems are designed for security, scalability, performance, and maintainability

Tech Environment

• Languages: Go, Python

• Frameworks / Protocols: gRPC, Protocol Buffers

• Architecture: Microservices

• Cloud: AWS (ECS, Lambda, EventBridge, Athena), GCP (Storage, Pub/Sub)

• Infrastructure as Code: Terraform, CloudFormation

• Workflow Orchestration: Apache Airflow (MWAA)

• Databases: DynamoDB, RDS, BigQuery

• Monitoring & Logging: CloudWatch, Datadog

• CI/CD: GitHub Actions, CodePipeline

• Collaboration: Slack, Teams, Google Meet

• Project Management: Jira

• Methodology: Scrum

What We’re Looking For

Core Experience

• 3+ years of experience building APIs using Go or Python

• Strong understanding of Protocol Buffers / gRPC-based systems

• Experience designing and building scalable backend or data systems

• Hands-on experience with cloud infrastructure (AWS and/or GCP)

Capabilities That Matter

• Ability to design systems with security, scalability, and performance in mind

• Experience contributing to technical decisions (languages, frameworks, architecture)

• Comfortable working across data pipelines, APIs, and infrastructure

• Strong problem-solving skills—able to break down complex technical challenges

• Clear communicator—can explain technical concepts to both technical and non-technical stakeholders

Mindset & Behaviours

• Naturally curious—driven to understand why systems work the way they do

• Open to feedback and continuously improving

• Takes ownership of problems and drives them through to resolution

• Comfortable working in fast-moving, ambiguous environments

Nice to Have

• Experience with Apache Airflow

• Experience with RDBMS and/or NoSQL databases

• Experience with Datadog or similar observability tools

• Strong understanding of logging and monitoring best practices

• Experience provisioning infrastructure using Terraform

Why This Role

• Work on high-impact data infrastructure powering real business decisions

• Exposure to modern cloud architecture and distributed systems

• Opportunity to influence platform design and technical direction

• Collaborate with experienced engineers in a high-performing, remote environment