Back End Engineer

Senior FullStack Engineer
WPP Open · Engineering · Gurugram

About the job:

WPP Open is WPP's AI-enabled marketing operating system, used by brands and agencies around the world. Our engineering teams in India build and run it alongside colleagues in the UK and Europe. As a Senior Engineer you own a component or service, from its design and API to its tests and production health, and you mentor other engineers. The role is backend-heavy, and you also build the React interfaces for the features you deliver. Our interviews are practical and hands-on.

Responsibilities:

• Design, build, test and ship production code every sprint, test-first.
• Own a component or service end to end: its design, OpenAPI contract, data model, Playwright test suite, monitoring and runbook.
• Write design documents and architecture decision records for your component, and review other engineers' code with rigour and care.
• Choose between AWS Lambda and Kubernetes for your workloads, and build and maintain the CI/CD pipeline that ships them.
• Lead triage when your component fails, write post-incident reviews and fix the underlying causes.
• Build production AI features on the Anthropic and OpenAI APIs, and maintain your component's Claude Code configuration and MCP server.
• Explain technical trade-offs to product and delivery colleagues, including colleagues in other regions.
• Mentor less experienced engineers and help new joiners become productive quickly.

Minimum qualifications:
• Bachelor's degree or equivalent practical experience.

• 5 years of professional software development in TypeScript and Node.js or Python.

• 3 years of experience testing, maintaining or launching production software, and 1 year of experience with software design and architecture.

• Experience working in globally distributed teams across time zones, with stakeholders in other regions.

• Backend language and craft. You write idiomatic, strictly typed backend code in TypeScript with Node.js or in Python, with runtime validation at service boundaries using Zod or Pydantic. You understand concurrency in your language well enough to recognise blocking work and profile a misbehaving service, and you know NestJS, Fastify or FastAPI in depth.

• React and frontend. You choose and justify state-management approaches in React, keep rendering fast through memoisation, lazy loading and code splitting, and meet WCAG AA accessibility on the 
features you build. You contribute components to the design system and can build interfaces that stream responses from AI services.

• APIs and data formats. You design REST APIs with OpenAPI and own the contract for your service, including versioning, backwards compatibility, idempotency keys, rate limiting and webhooks. You know when to use JSON and when to use Protocol Buffers, and you check schema compatibility automatically in your pipeline.

• Data. You design PostgreSQL schemas and change them without downtime, tune slow queries and understand transaction isolation. You model data well in both DynamoDB and MongoDB, use Redis for caching, and choose the right store for each workload with clear reasons.

• Asynchronous systems and reliability. You design producers and consumers on queues such as SQS and BullMQ or Celery, with retries, dead-letter queues and idempotent handlers so that at-least-once  delivery is safe. You recognise when these safeguards are needed before anyone asks.

• Cloud and platform. You design services on AWS Lambda, with sensible function boundaries, concurrency settings, dead-letter queues and Step Functions or EventBridge where needed, all defined 
as code with AWS CDK or SAM. You operate workloads on Kubernetes, including Helm, autoscaling, rollouts and rollbacks, and you choose between serverless and containers for each workload.

• Testing and quality. You practise test-driven development and apply it to the design of whole components, not just individual functions. You write integration and contract tests with Testcontainers and
own your component's Playwright test suite, including test data, parallel runs and removing flaky tests.

• Observability and performance. You instrument services with OpenTelemetry, own the Datadog monitors, alerts and CloudWatch alarms for your component, and lead triage and post-incident reviews 
when it fails. You set performance budgets, profile under realistic load, and find memory leaks and blocking work in production.

• Security and identity. You implement OAuth 2.0 and OpenID Connect end to end, including the authorisation-code flow with PKCE and client credentials for service-to-service calls. You design role based access control, rotate secrets and keys, and secure your supply chain with dependency scanning and static analysis in the pipeline.

• Architecture and design. You design a service from a short brief, write design documents and architecture decision records that name the trade-offs, and design for backwards compatibility so that 
changes do not break the people who depend on your service.

• Engineering practices. You work trunk-based with GitHub Flow and hold others to it in code review. You build and maintain CI/CD pipelines, treat every dependency as something to pin and upgrade on a  regular cadence, and write documentation for the people who will read it. AI-first engineering and LLMs. You build production features on the Anthropic and OpenAI APIs, using tool calling, structured output and evaluations, and you track token usage and cost. You maintain the Claude Code configuration for your component, including CLAUDE.md, skills and subagents, and have built an MCP server that exposes your service to AI agents.

• Communication, collaboration and initiative. You communicate clearly and concisely, and you explain technical trade-offs to product, design and delivery colleagues in terms they can act on. You understand problems quickly and confirm shared understanding before acting. You collaborate well across locations and time zones, working asynchronously and handing over cleanly. You are proactive: you spot problems before you are asked, propose solutions and improvements of your own, and see them through without waiting for instructions.

• Leadership and behaviours. You review others' code with rigour and care, mentor less experienced engineers, and disagree openly when you need to and then commit fully to the decision. You say "I don't know" when you don't, and you dig in until you do.

Preferred qualifications:
• B.Tech or B.E. in Computer Science, Information Technology or a related field.
• Experience with monorepo tooling such as Nx or Turborepo at scale.
• Experience with Kafka and change data capture.
• Experience with behaviour-driven development using Cucumber.
• Experience with Bigtable.
• Experience shipping an AI agent with LangGraph, Google ADK or the Anthropic Agent SDK.
• Experience configuring an identity provider such as Okta, Keycloak or Cognito.