Senior Backend Engineer

Who We Are You've ordered from Just Eat Takeaway. You've bought and sold on OLX. You've paid with PayU. That's Prosus, a leading global technology technology company, based in Europe, powering the world's leading lifestyle brands and connecting two billion people across India, Latin America, Europe and beyond. We own and invest in 100+ companies across food delivery, quick commerce, fintech and experiences, tied together by an AI-driven ecosystem that delivers seamless, personalised experiences at a scale few companies can match. We've built one of the world's largest agentic workforces. 60,000+ AI agents automating complex workflows and creating the equivalent of 1,000 full-time employees in organisational capacity. Our people don't just use AI. They design it, deploy it, and push what it can do. Through our Ventures business, we're backing the next frontier: AI and commerce, the digital AI workforce, and emerging technologies like robotics, drones and synthetic biology. Context Toqi is an AI assistant platform with ~150k users and rapid growth. The system is a monorepo: React Native (Expo) mobile app, Go API gateway, Python AI agent, Postgres + Redis, deployed on GCP Cloud Run via Terraform. The Role As a Senior Backend Engineer you own services end to end — design, implementation, deployment, monitoring and the pager. Anything that changes an API contract, a database schema or a cost profile gets a short design note circulated before the code is written. Judgement calls on data modelling, failure modes and where to spend the latency budget sit with you rather than being escalated by default. Seniority here is measured in what the rest of the team can rely on. You review backend pull requests with the same care you expect on your own, leave the codebase more legible than you found it, and raise trade-offs early — where a product request would cost more in reliability, inference spend or long-term maintenance than it returns, we want that argued rather than absorbed quietly. Primary Responsibility — API Gateway (Go) Design, build and maintain REST and WebSocket endpoints serving the mobile app and WhatsApp surface Own domain models, repository interfaces, and database migrations Add new handlers and services as product features require Define and version shared API contracts (protobuf) consumed by the client Maintain authentication, authorisation and session handling Enforce rate limits, quotas and abuse protection Instrument services: structured logging, metrics, tracing and useful alerts Keep linters, formatting, and tests passing Secondary Responsibility — AI Agent Services (Python) Extend the agent runtime: tool calling, orchestration, and third-party or portfolio API integrations Manage prompt and model configuration, versioning, and evaluation harnesses Control inference latency and cost through caching, batching, model routing and token budgets Build and maintain the memory and context layer on Postgres and Redis Handle asynchronous and long-running work: queues, retries, idempotency, dead-letter paths Tertiary Responsibility — Data, Infra & Cross-Cutting Postgres schema design, indexing, query performance and connection pooling Redis for caching, ephemeral state and pub/sub behind the real-time chat layer Maintain and extend infrastructure as code (Terraform on GCP): Cloud Run services, secrets, IAM Assist with deploys, rollbacks, and environment configuration Implement data retention, deletion and export paths required under GDPR and LGPD Support incident response and write up what happened afterwards Engineering Practices Branch from dev, open PRs targeting dev, follow Conventional Commits Run pre-merge quality checks before pushing Write PRs with structured descriptions (why / what changed / how to test) Collaborate on the weekly release cadence Participate in code review (automated + peer) Expectations as We Scale Past 150k Users Harden the backend for scale: p95 latency, error rates, backpressure and graceful degradation Forecast capacity and cost across infrastructure and model inference Contribute to feature-flagged rollouts and zero-downtime migrations Improve observability so problems surface before users report them Help onboard future engineers to the backend codebase Our Diversity & Inclusion Commitment We respect the dignity and human rights of individuals and communities wherever we operate in the world. Building an inclusive workplace where everyone feels welcome and can thrive is critical for us. We provide access to education, which helps everyone understand the important role they play and the positive impact they can have.