Senior Backend Engineer, Toqi (AI Life Assistant)

Prosus; Amsterdam; On-site; EUR 90,000 - 130,000; Full time

Job summary

Prosus in Amsterdam is seeking a Senior Backend Engineer to own services end to end — from design and implementation to deployment, monitoring and pager duties. You will shape API contracts, database schemas and cost profiles, review backend PRs with care, and ensure a legible codebase while balancing reliability and cost.

You will focus on API Gateway (Go) and AI Agent Services (Python) with Postgres and Redis, and IaC via Terraform on GCP, delivering scalable, observable backend systems for a

Qualifications

• Backend development experience in Go/Python preferred.
• Experience designing and maintaining REST/WebSocket APIs.
• Familiarity with data modeling and database migrations.

Responsibilities

• 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
• 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
• 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
• 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)
• 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

Skills

Backend development

Tools

Go

Python

PostgreSQL

Redis

Terraform

GCP

Job description

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.