Platform Engineer (up to £160k)

Dex; Greater London; On-site; GBP 110,000 - 140,000; Full time

Job summary

Dex is partnering with a rapidly growing AI platform based in London. This is a senior/staff-level platform engineering role focused on deep technical ownership and internal developer experience.

You will evolve AWS serverless architecture, own Pulumi-based CI/CD pipelines, and build observability dashboards for a 45+ engineer team to enable scalable deployments across regions.

Qualifications

• Specialised in platform or developer experience at a cloud-native SaaS company.
• Writes production TypeScript in a monorepo.
• Deep AWS serverless experience (Lambda, DynamoDB, Aurora, EventBridge).
• Refactors infrastructure-as-code (Pulumi, CDK, Terraform, or SST).
• Built observability systems with dashboards, SLOs, and alerts.

Responsibilities

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

Job description

This role is with one of Dex's trusted partner companies. We work closely with their teams to truly understand their culture, goals, and what they're looking for, so we can match you with the right opportunity and give you context about the role before you commit to a process.

The role

This company is building an Agentic Operating System for a critical enterprise function, where AI agents are the core product, not an afterthought. They've secured significant funding from leading investors and are experiencing rapid growth, scaling their platform to serve a rapidly expanding enterprise customer base. They are recognised as one of Europe's fastest-growing companies.

You'll join a dedicated platform team, serving a rapidly growing engineering organisation of 45+ engineers. This isn't a DevOps or SRE role; you'll write production TypeScript in a monorepo, owning the shared foundations that enable daily deployments across nine product domains. Your impact is direct: you'll evolve their AWS serverless architecture for 10x growth, multi-region high availability, and data residency, setting the pace for the entire engineering team. This is a senior or staff-level seat, focused on deep technical ownership and internal developer experience.

The work

• Evolve a critical AWS serverless architecture (Lambda, DynamoDB, Aurora, EventBridge) to support 10x growth, multi-region high availability, and data residency.
• Own and extend GitHub Actions pipelines and Pulumi infrastructure-as-code, ensuring robust, scalable deployment for 45+ engineers.
• Design and implement Datadog dashboards, SLOs, and alerts that proactively identify issues before customers are impacted.
• Write production-grade TypeScript within a shared monorepo, building the core tooling and services that empower product teams.
• Automate away toil, building internal tools and workflows that improve developer velocity and experience across the organisation.

What You Bring

• You've deliberately specialised in platform or developer experience at a cloud-native SaaS company (50–500 engineers), not a recent pivot from DevOps or SRE.
• You write production code in TypeScript; a scripting-only background (Bash/YAML) isn't a fit for this team.
• Deep, first-hand experience with AWS serverless (Lambda, DynamoDB, Aurora, EventBridge, IAM, networking), understanding the trade-offs.
• You've refactored a real infrastructure-as-code codebase (Pulumi, CDK, Terraform, or SST) and built reusable CI/CD workflows, deploy gates, and preview environments.
• You've built observability systems (dashboards, SLOs, alerts) that are genuinely relied upon and correctly page humans.

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