Senior Backend Engineer (Data serving)

Pleo; København; Hybrid; DKK 900,000 - 1,350,000; Full time

Benefits offered by this job

Your own Pleo card

Lunch is on us

Private healthcare

25 days annual leave

Hybrid and remote options

Mental health support program

Paid parental leave

Job summary

Pleo, a fast-growing spend-management company, is seeking a Senior Backend Engineer for the Data Serving team. You will own the boundary between raw product data and consumers, building APIs and a low-latency serving layer used by dashboards, AI agents, and customers.

You’ll work with Kotlin-based services on AWS/GCP, Docker, Kubernetes, and modern data tools, focusing on reliability, performance, and contract-driven data sharing across teams.

Qualifications

• Strong backend experience building and owning reporting and analytics API services.
• Focus on reliability, latency, and SLOs in production environments.
• Experience designing API boundaries with stable contracts for downstream consumers.
• Expertise in read-heavy systems, indexing, caching, and SQL performance.
• Deep JVM experience, especially Kotlin, with cloud and container orchestration.

Responsibilities

• Build and own the Data API boundary with versioned, low-latency endpoints.
• Design read models, indexes, and caching for fast queries in Postgres and OLAP stores.
• Integrate with Kotlin-based product backend services to surface correct data.
• Ensure reliability and performance with monitoring, incident response, and SLOs.
• Define contracts between ingestion/aggregation and serving databases.
• Collaborate on securing APIs with standard authentication/authorization.
• Develop near-real-time data aggregation across Pleo services.
• Define metadata, lineage, governance for explainable and auditable data.
• Own access control with row/column-level security and audit trails.

Skills

Backend engineering

API design

Performance tuning

SQL querying

Kotlin

Tools

Docker

Kubernetes

PostgreSQL

Kafka

BigQuery

dbt

Python

AWS

GCP

Job description

About Pleo

Messy spend management is tricky business. And tedious processes are a lose-lose situation for all involved, not just finance. At Pleo, we're changing that. We build spend solutions that make managing money seamless, empowering, and surprisingly effective for finance teams and employees alike - with a vision to help all businesses ‘go beyond’.

Messy spend management is tricky business. And tedious processes are a lose-lose situation for all involved, not just finance. At Pleo, we're changing that. We build spend solutions that make managing money seamless, empowering, and surprisingly effective for finance teams and employees alike - with a vision to help all businesses ‘go beyond’. The word ‘Pleo’ actually means ‘more than you’d expect’, and living by that mantra has been the secret to our success over the last 10 years. Now, we’re at a pivotal moment in our journey; every move we make has a direct impact on our 40,000+ customers, our business, and our collective success. We need people who take pride in uncovering customer needs, who turn complex problems into simple solutions, challenge the way things are done (respectfully), and always aim high. With great ambitions driving us forward, we can’t say we’ve got this whole thing figured out. And frankly, that’s half the fun! What we can say is that we’re a driven, progressive, and, importantly, a kind bunch of 850+ people from over 100 nationalities, all committed to delivering the future of business spending, together.

About The Role

We're looking for a Senior Backend Engineer to join the Data Serving team that owns the production-grade boundary between Pleo's raw product data and everyone who consumes it, including internal product teams, AI agents, and customers directly accessing their own data. This Senior Backend Engineer role builds and owns that boundary: APIs and the low-latency serving layer underneath it. You will build customer-facing infrastructure where contract stability and latency are non-negotiable, and where the clean abstraction you maintain is what lets every downstream consumer trust the data without ever touching a raw source.

Who You’ll Be Working With And Reporting To

You will report to our VP of Data, and work closely with our Staff Data Platform Engineer, Data Engineers, Product Managers and others Engineers across the business. You'll also coordinate closely with the GenAI Platform and Data Infrastructure teams.

What You’ll Be Doing

• Build and own the Data API boundary: delivering clean, versioned, and performant endpoints for internal dashboards, customer-facing features, and third-party tools (e.g., Fivetran connectors via incremental syncs and cursor pagination).
• Design and optimise the read models, indexes, and caching strategies in Postgres (and future OLAP stores) to guarantee low-latency query performance.
• Build reliable integrations with Pleo’s Kotlin-based product backend services to ensure the serving layer surfaces the correct data required for a customer facing feature.
• Own the reliability and performance of the services you build: monitoring, incident response, and SLOs appropriate to customer-facing infrastructure.
• Partner with Data Engineers to define clean contracts between the ingestion/aggregation layer and the serving DB, ensuring read patterns match storage schemas.
• Partner with the Authorization team to secure APIs using industry-standard authentication and authorization protocols.
• Build a near-real-time data aggregation service to collect and unify data across Pleo services.
• Design metadata, lineage, and governance capabilities that make the serving layer explainable, auditable, and trustworthy.
• Own access control and permission management services, including row and column-level data access with full audit trails.

To put things into context, you can expect to work with the following tech stack: AWS (product side), GCP (data side), Docker, Kubernetes, BigQuery, PostgreSQL dbt, Kafka, Airflow, Python, Kotlin and more!

What You Bring

• Strong backend engineering experience building and owning reporting and analytics API services and serving-layer infrastructure.
• A mindset focusing on reliability, latency, and SLOs.
• Experience owning API boundary layers including clean endpoint design, versioning, contract stability, and ensuring downstream consumers are never exposed to raw data sources.
• Strong expertise designing performant read-heavy systems, including relational database optimisation, indexing strategies, materialised views, caching, and API performance tuning.
• Solid database fundamentals (SQL and non-SQL) and strong SQL querying skills, as well as deep expertise in Kafka.
• Deep experience with a JVM-based language (Pleo's product backend is Kotlin-based).
• AWS or GCP with Kubernetes experience. You must be familiar with configuring, deploying and operating containerised applications in a k8s environment.
• Experience working at the boundary between data systems and product backend services, with a real understanding of the operational differences between the two.
• The ability to move quickly and independently. This is a hands-on delivery role with clear scope, not an architecture or advisory engagement.
• Experience in fintech, payments, or other regulated product environments.

Why is this role a good fit for you

• You are passionate about building systems that serve other engineers.
• You understand what it means to design, build and maintain services with high performance, availability and reliability requirements.
• You have a very deep understanding of the data world and know how to bridge the gap between data and engineering.

This role is not a good fit for you if

• You need to operate within very large and structured teams with clear hierarchy. This role sits within a small and specialist team with a lot of autonomy.
• You do not wish to be responsible for services with high availability requirements. You will be held accountable for the quality and availability of those services alongside your team.
• You prefer to be handed over clearly defined scope of work. You will be expected to define and design the solutions as much as building them.

How You’ll Develop In This Role

• Get deep into the current state: the upstream Kotlin services the serving layer will pull from, the internal consumers already waiting on the API (Data & AI Products, GenAI Platform), and any prototype serving logic that needs to be replaced or formalised.
• Ship the first production version of the Reporting API (a defined set of endpoints with agreed contracts, versioning, and SLOs) with at least one internal consumer live against it.
• Establish the access control, tenant isolation, and row/column-level security model for the API. You will have proven out low-latency query performance on Postgres, with clear metrics around reliability and SLOs, and established a clear architectural benchmark to understand when (or if) an OLAP layer would ever be necessary.

We can hire on a remote, hybrid or in-person set-up in any of the locations listed on the advert but you will need to be physically based in the country of your choice with a valid right to work. We are unable to offer visa sponsorship for this role in any of the listed locations.

Show Me The Benefits

• Your own Pleo card (no more out-of-pocket spending!)
• Lunch is on us for your work days - enjoy catered meals or receive a lunch allowance based on your local office
• Comprehensive private healthcare - depending on your location, coverage options include Vitality, Alan or Médis.
• 25 days of annual leave + public holidays (additional days may apply in select countries based on local standards).
• For our Team, we offer both hybrid and fully remote working options.
• We use MyndUp to give our employees access to free mental health and well-being support with great success so far
• Paid parental leave - we want to make sure that we’re supportive of families and help you feel that you don't have to compromise your family due to work

The interview process

• Intro call: A 30-minute chat with our Talent Partner to discuss the role and your background.
• Core skills test: An async AI-assisted programming test to assess your coding fundamentals.
• Hiring Manager interview: A 60-minute chat deep diving into your experience.
• Pleo Challenge: A 75-minute system design interview focusing on your architecture, infrastructure and problem-solving skills.

Transparency is important to us so we also wanted to share some insights about what we’re looking for in applications to ensure you can set yourself up for success!