Senior Polyglot Engineer

Employer: Klarna

Location: Warsaw (hybrid work: 2-3 days in the office)

Rate: 170 - 195 PLN per hour

Cooperation model: B2B or Employment Contract

Start date: ASAP

Duration: long-term agreement

Recruitment process: 1 timed Abstract and Logical Reasoning Test (up to 15 minutes); 1 short interview (up to 30 minutes)

Do you want to play a key role in revolutionizing the future of finance? Join Klarna - a global leader in deferred payments, with over 85 million active users and 2.5 million transactions processed daily! As a pioneer in modern payment solutions, Klarna is developing innovative methods that streamline the shopping experience, enhance transaction security, and expand the availability of purchasing options. 

We're seeking individuals eager to achieve remarkable results and share their bold vision to redefine the future of payments and fintech. Send us your CV - we can’t wait to meet you!

Your role is:

-> To take part in building a cross-platform money movement engine seamlessly connecting Klarna users (and non-users) across markets, currencies (incl. crypto), and payment networks;

-> To work as a full-stack engineer with strong backend focus;

-> To build and maintain scalable backend services in Java, Python, and TypeScript;

-> To develop high-performance APIs powering P2P and cross-border money transfer experiences in Klarna’s app and web products;

-> To design and maintain secure, observable, and fault-tolerant infrastructure;

-> To own the full development lifecycle—from design to deploy and monitor;

-> To integrate with third-party money movement APIs (e.g. banking and crypto API providers, banking partners, SEPA, etc.);

-> To ensure compliance with Klarna’s security, identity, KYC, and AML flows;

-> To build robust and secure payment orchestration and settlement logic;

-> To work with Klarna-internal teams (e.g. Payments, Identity, Customer Support) to reuse or extend foundational capabilities;

-> To understand and plug into Klarna’s existing infra (e.g. PubSub events, internal auth models, mobile architecture);

-> To build feature-rich AI powered UIs for chat-based money transfers, payment link generation, FX tracking, and transaction history;

-> To contribute to UI codebases (TypeScript/React/React Native) as needed.

Your skills and experiences:

-> 8+ years of experience with NodeJS, JavaScript/TypeScript, React, and React Native;

-> Experience with Redis and PostgreSQL;

-> Strong emphasis on backend development, particularly with Express and related technologies;

-> Familiarity with AWS services such as DynamoDB, Firehose, and Elasticache;

-> Experience with tools like Datadog and Elasticsearch;

-> Prior experience with Klarna payments API (PACS, OPF, etc.) and understanding of how orders flow through various services from creation to merchant capture;

-> Strong educational background in Computer Science, Information Technology, or a related field;

-> Language proficiency: Advanced English (minimum B2 level).

Nice to have:

+ Experience with payments, remittances, or banking APIs;

+ Klarna experience (or Klarna platform knowledge—e.g. routing layers, service registration, AuthN/AuthZ models);

+ Comfortable contributing to web or app UI codebases (React, React Native).

Our client offers:

+ Great opportunity for personal development in a stable and friendly large multinational company;

+ Start-up mentality, small agile teams;

+ Global Reach: Impact millions with seamless shopping and payments;

+ Career growth and additional education.

If interested, please apply safely through this portal (application rules are in accordance with GDPR). Employment agency Nr 17138.