Senior Platform Engineer — AWS Serverless & DX

Dex; Greater London; On-site; GBP 120,000 - 180,000; Full time

Job summary

Dex partners with a fast-growing cloud-native SaaS company building an Agentic Operating System where AI agents are core. You will join a platform team of 45+ engineers, delivering deep technical ownership and exceptional developer experience.

You’ll evolve AWS serverless architecture for 10x growth, extend Pulumi-based infrastructure, and write production TypeScript in a shared monorepo to empower multiple product domains.

Qualifications

• Specialised in platform or developer experience at a cloud-native SaaS with 50–500 engineers.
• Write production TypeScript code; scripting-only background isn’t a fit.
• Deep AWS serverless experience (Lambda, DynamoDB, Aurora, EventBridge, IAM, networking).
• Refactored an IaC codebase (Pulumi, CDK, Terraform, or SST) and built reusable CI/CD workflows and preview environments.
• Built observability systems (dashboards, SLOs, alerts) that are relied upon.

Responsibilities

• Evolve AWS serverless architecture for 10x growth and multi-region HA.
• Own and extend GitHub Actions pipelines and Pulumi IaC.
• Design and implement Datadog dashboards, SLOs, and alerts.
• Write production-grade TypeScript in a shared monorepo.
• Automate toil with internal tools to boost developer velocity.

Skills

Platform engineering

Developer experience

TypeScript

AWS serverless

CI/CD workflows

Observability

Tools

Pulumi

CDK

Terraform

SST

GitHub Actions

AWS

Job description

Dex partners with a fast-growing cloud-native SaaS company building an Agentic Operating System where AI agents are core. You will join a platform team of 45+ engineers, delivering deep technical ownership and exceptional developer experience.

You’ll evolve AWS serverless architecture for 10x growth, extend Pulumi-based infrastructure, and write production TypeScript in a shared monorepo to empower multiple product domains.