Senior Application Platform Engineer

ImpacT Hire is supporting one of our clients – an international technology company building an enterprise application platform where business users can access and run governed applications from a single workspace.
We are looking for a Senior Application Platform Engineer to join a small product engineering team responsible for building an internal, developer-facing SDK and the applications running on top of it.

The SDK is at the core of this role. You will own its client library, developer-facing contracts, packaging, documentation, reference application, and ongoing evolution. This goes beyond building APIs or reusable internal components – the SDK is a product for other developers and needs to provide a stable, intuitive, and well-documented development experience.
The SDK itself is built in-house by the team, so no previous knowledge of the specific SDK or platform is required. What matters is previous experience designing and building an SDK, library, developer platform, or comparable developer-facing product.

This is a highly hands-on senior role combining SDK and platform engineering, full-stack development, AWS infrastructure, security, and AI-enabled applications. As part of a deliberately small team, you will both design and build, with significant ownership over technical decisions and engineering standards.

Responsibilities:
➢ Take end-to-end ownership of the internal SDK, including its client library, developer-facing API and contracts, platform-side services, packaging, documentation, reference application, and evolution;
➢ Design stable and intuitive SDK interfaces that other developers can confidently build applications against;
➢ Make the SDK real by building production applications on top of it – each application should serve both as a product and as proof that the SDK works effectively;
➢ Develop backend platform services using Node.js and TypeScript and frontend applications using React;
➢ Build governed applications covering environment connectivity, Single Sign-On, identity propagation to the data layer, monitoring, health checks, and controlled AI usage;
➢ Build different types of applications, including AI-native data applications, operational and workflow tools, and integrated dashboards;
➢ Integrate applications with enterprise platforms and services such as Jira, Grafana, Salesforce, and similar systems;
➢ Work with MySQL (AWS RDS) across the platform and SDK layer and DynamoDB within applications;
➢ Build and operate both serverless and container-based workloads on AWS, including Lambda, API Gateway, Kubernetes, and ECS;
➢ Implement AI capabilities using AWS Bedrock, including metering, budgets, quotas, usage tracking, and cost reporting;
➢ Own production delivery, including Infrastructure as Code with Terraform and CI/CD pipelines with Azure DevOps;
➢ Implement versioning, post-deployment smoke tests, automated rollback, monitoring, alarms, and cost controls;
➢ Establish and enforce engineering standards, perform code reviews, and mentor other engineers within the team;
➢ Use AI coding agents throughout the development lifecycle for design, implementation, testing, review, and documentation.

Tech Stack:
➢ Backend: Node.js, TypeScript;
➢ Frontend: React;
➢ Databases: MySQL (AWS RDS) for the platform and SDK layer; DynamoDB for applications;
➢ Platform: Kubernetes;
➢ Cloud: AWS – both serverless (Lambda, API Gateway) and container-based workloads (Kubernetes, ECS);
➢ Infrastructure as Code: Terraform;
➢ CI/CD: Azure DevOps;
➢ AI: AWS Bedrock.

Requirements:
➢ 6+ years of experience building and operating production software, including experience within a startup or small product engineering team with end-to-end delivery ownership;
➢ Strong SDK or developer platform experience – this is a core requirement for the role. You have designed and shipped a library, SDK, platform service, internal developer platform, or comparable developer-facing solution consumed by other engineers;
➢ Experience owning the broader lifecycle of an SDK or developer-facing library – including its contracts/interfaces, packaging, documentation, versioning, and evolution – rather than only developing APIs or reusable components;
➢ Strong understanding of API and SDK design and the long-term implications of developer-facing interface decisions;
➢ Strong hands-on experience with Node.js and TypeScript;
➢ Frontend development experience with React;
➢ Experience working with relational and NoSQL databases, ideally MySQL and DynamoDB;
➢ Strong hands-on AWS experience across both serverless and container-based architectures – experience with both is required;
➢ Experience with Kubernetes and containerized production workloads;
➢ Experience with Infrastructure as Code, preferably Terraform, and production CI/CD environments;
➢ Experience with identity and multi-tenant architectures, including OIDC, session/context propagation, tenant isolation, and row-level data scoping;
➢ Practical FinOps experience managing costs for live cloud and/or AI workloads through budgets, quotas, alerts, and usage reporting;
➢ Strong understanding of application security, including secrets management, untrusted input, generated code, and common web security risks;
➢ Advanced practical use of AI coding agents throughout the SDLC, including development, testing, code review, and documentation;
➢ Experience integrating AI capabilities into production applications, with a clear understanding of both the strengths and limitations of agentic development;
➢ Working proficiency in English within an international, distributed team.

Nice to Have:
➢ Experience with AWS Bedrock or other managed LLM services;
➢ Experience with MCP servers and tools;
➢ Knowledge of production LLM application patterns, including prompt design, model selection based on quality and cost, evaluation of AI outputs, and sandboxing AI-generated code;
➢ Experience with integration platforms or iPaaS solutions;
➢ Experience integrating with enterprise platforms such as Salesforce, SAP, Jira, or Grafana;
➢ Hands-on experience working within SOC 2 or ISO 27001 environments.

What They Offer:
➢ Professional development and long-term career opportunities;
➢ Online courses and continuous learning opportunities;
➢ Opportunity to take ownership of an in-house SDK and developer platform and influence how it evolves;
➢ Significant technical ownership within a small product engineering team;
➢ Hands-on exposure to modern AI and agentic engineering practices;
➢ Online sports activities;
➢ Team buildings and Christmas events.

If you enjoy building products for other developers, thinking carefully about SDK design and developer experience, and owning technical decisions from the client library through cloud infrastructure and production, this role offers the opportunity to shape an in-house platform and its SDK from an early stage.