Principal Software Engineer

Position Summary:

Swiftly is searching for a Principal Software Engineer to lead the architecture of our ads and martech platform: the systems that author retail media campaigns, generate creatives and serve ads to shoppers through The Trade Desk. The platform spans a Go ad server built for low-latency bid requests, Python services on Azure Functions for campaign authoring and tenant configuration, Kotlin/Quarkus services we are carving apart, and a shared PostgreSQL schema managed as code. This role will set technical direction across these teams, lead a tenant-by-tenant migration off legacy services without downtime, and stay hands-on in the hardest code.

Responsibilities Include:

• Work with and provide direction to the teams that build Swiftly's ads and martech platform, including the Go ad server, campaign authoring, the tenant and capability registry, creative generation and personalized-ad services
• Architect, code and maintain large scale distributed systems with complex requirements
• Lead the incremental migration of campaign authoring and The Trade Desk write path off a Kotlin/Quarkus service, one retailer at a time, using per-tenant ownership switches, database write guards and shadow-diff dry runs to cut over safely
• Own the performance and reliability of the Go ad server against strict SLOs (p50 at or under 40 ms, p99 at or under 1 s, 2 s hard deadline), using in-process caching, circuit breakers, connection pooling and profiling
• Design the data contracts shared between services: declarative schema-as-code with Atlas, versioned database views as serving contracts, and transactional outbox and projector patterns for side effects
• Partner with data engineering on Databricks pipelines for personalized rankings, identity resolution and the impression data that feeds attribution and iROAS
• Build safe, auditable integrations with The Trade Desk GraphQL API, Salesforce and creative-rendering services, with idempotent, lock-protected pushes and full write audit history
• Utilize expertise with microservices architecture and database design
• Operate production services, including on-call and incident management
• Contribute to a multi-tenant platform architecture
• Guide the platform from AKS with ArgoCD and Kustomize toward Azure Container Apps and Azure Functions, with runtime configuration in Azure App Configuration and identity through Entra ID and Key Vault
• Set the engineering quality bar: strict typing and linting, unit, integration and end-to-end tests with Testcontainers, CodeQL and dependency scanning, release automation in GitHub Actions, and AI-assisted development
• Working collaboratively in an ambiguous, fast-paced environment
• Take ownership of domain from the ground up, from architectural decisions to coding to testing to operations
• Other related duties as assigned

Required Qualifications:

• Bachelor of Science in Computer Science, Computer Engineering, Mathematics or a related field or comparable industry experience
• 10+ years of industry experience designing, building, and maintaining large-scale software services, ideally in a multi-tenant environment
• Confidence writing production code in Go and Python, and working in Kotlin or Java services
• Expertise with PostgreSQL (query performance, migrations, views), Kubernetes, event streaming such as Azure Event Hubs or Kafka, and API frameworks such as FastAPI or Quarkus
• Experience building and running services on Azure and/or AWS
• Experience building low-latency, high-throughput services against defined SLOs, with observability through OpenTelemetry, Prometheus, Loki, Pyroscope and Grafana
• Experience with CI/CD in GitHub Actions, GitOps deployment and infrastructure as code such as Terraform
• Ad tech experience: ad servers, DSPs such as The Trade Desk, impression tracking, and campaign measurement or attribution
• Experience with Databricks or Spark data pipelines
• Experience with Atlas schema migrations, SQLAlchemy/SQLModel or pgx, and Azure Functions or Container Apps
• Experience using AI coding agents in daily development
• This position is not eligible for visa sponsorship. Applicants must be authorized to work in the U.S. without the need for current or future sponsorship

Preferred Qualifications:

• Experience with retail-oriented solutions and Saas
• Mix of startup and large software company experience