Yonatan Karp-Rudin Download CV

Yonatan Karp-Rudin

Arrival Plaza

Staff Software Engineer: Kotlin, Spring Boot, Kafka. Pick a district to walk in.

I turn messy backend domains into systems a team can run and change.

Open to Staff+ backend roles in Israel, on-site or hybrid.

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Yonatan Karp-Rudin

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RRoofWhat's next

If your backend domain needs untangling, let's talk.

My strongest fit is Staff+ backend work where the domain has to become one system the whole team understands.

  • Staff+ backend roles in Israel, on-site or hybrid.
  • Payments, risk, compliance, or platform architecture.
  • OSS, technical writing, and teaching.

Get in touch at the Post Office →

R

RoofWhat's next

If your backend domain needs untangling, let's talk.

My strongest fit is Staff+ backend work where the domain has to become one system the whole team understands.

Based in
Berlin, Germany
Best for
Teams turning scattered services and vendors into one platform

I am useful when the team needs clarity as much as code

  • Important work that no team has clearly claimed.
  • Backend systems that run on context nobody wrote down.
  • Repeated problems that deserve a tool.
  • Teams that want someone to find the path and teach it.

What I try to leave behind on a team

People use the same words for the system and rely less on folklore. Tradeoffs are written down where the team can find and challenge them later. A problem that keeps coming back becomes an example, a library or a template anyone can pick up, and the system gets easier to change because more people know why it works the way it does.

Get in touch

At the Post Office: email and the CV →

7Billie, BerlinOct 2025 – Present

Staff Software Engineer, Payments

Case study · Compliance platform Creating a new service boundary for compliance workflows.

Case study · Engineering leverage Turning repeated operational friction into shared tooling.

Responsible for the reliability of the payments and compliance platform: service boundaries, vendor integrations, migrations, and operational tooling.

  • Took third-party transaction monitoring live after shadow mode caught lost messages and transactions that could have cost about €55k.
  • Rebuilt the compliance service around hexagonal architecture and a transactional outbox.
  • Designed the dead-letter and replay pattern for payment services and shipped it as a shared Spring Boot library, now in 3 services.
7

Billie, Berlin, GermanyOct 2025 – Present

Staff Software Engineer, Payments

Responsible for the reliability of the payments and compliance platform: service boundaries, vendor integrations, migrations, and operational tooling.

What I did

  • Took third-party transaction monitoring live after shadow mode caught lost messages and transactions that could have cost about €55k.
  • Rebuilt the compliance service around hexagonal architecture and a transactional outbox.
  • Designed the dead-letter and replay pattern for payment services and shipped it as a shared Spring Boot library, now in 3 services.
  • Built on-call triage tooling used across about 80 production incidents, and a Backstage Payments Hub to replace Postman workflows.

Case study

Compliance platform

Creating a new service boundary for compliance workflows.

Context

Transaction monitoring, screening, and sanction checks crossed product rules, vendor behavior, alerts, and audit expectations.

Decision

I authored the technical spec and interfaces, led the transaction monitoring vendor integration, and covered Kafka DLT alerts, settlement reports, and compliance states in the service design.

Result

Shadow mode found lost messages and transactions that could have cost about €55k. Operational knowledge that was scattered now sits in one service teams can monitor and recover.

Case study

Engineering leverage

Turning repeated operational friction into shared tooling.

Context

Platform work gets expensive when incidents, cronjobs, migrations, and service setup depend on private memory.

Decision

I build Backstage tools, templates, migration plans, and upstream fixes when the reusable path beats another one-off patch.

Result

The dead-letter and replay library runs in 3 services, and the triage tooling was used across about 80 production incidents.

6Billie, BerlinApr 2025 – Oct 2025

Staff Software Engineer, Risk

Case study · Risk architecture Moving risk work toward explicit orchestration and contracts.

Moved risk decisions from Purchases into a dedicated orchestrator, took the graph fraud integration to production, and set the target architecture for buyer risk.

  • Moved risk decisions from Purchases to a Risk-owned orchestrator, from RFC to production.
  • Led the graph fraud integration to production, reducing fraud by 4-6%.
  • Authored the Buyer Risk Assessment target architecture and the tokenization specification.
6

Billie, Berlin, GermanyApr 2025 – Oct 2025

Staff Software Engineer, Risk

Moved risk decisions from Purchases into a dedicated orchestrator, took the graph fraud integration to production, and set the target architecture for buyer risk.

What I did

  • Moved risk decisions from Purchases to a Risk-owned orchestrator, from RFC to production.
  • Led the graph fraud integration to production, reducing fraud by 4-6%.
  • Authored the Buyer Risk Assessment target architecture and the tokenization specification.

Case study

Risk architecture

Moving risk work toward explicit orchestration and contracts.

Context

Risk decisions depended on multiple services, fraud providers, recurrent identification, tokenization, and direct debit behavior.

Decision

I co-designed the Risk Orchestrator, led the fraud vendor integration, and authored the Buyer Risk Assessment target architecture.

Result

Risk decisions now run through one orchestrator, and the fraud integration cut fraud by 4-6%.

5Billie, BerlinNov 2023 – Apr 2025

Senior Software Engineer, Risk

Built Risk's credit limit and fraud-labelling services, and moved risk signals to event-driven, engineering-owned pipelines.

  • Built a credit limit service and a fraud-labelling service from scratch.
  • Replaced synchronous Risk-Refinancing calls with the event-driven credit score our partner required to fund Pan-European refinancing.
  • Moved real-time fraud features from Data Science to Engineering.
5

Billie, Berlin, GermanyNov 2023 – Apr 2025

Senior Software Engineer, Risk

Built Risk's credit limit and fraud-labelling services, and moved risk signals to event-driven, engineering-owned pipelines.

What I did

  • Built a credit limit service and a fraud-labelling service from scratch.
  • Replaced synchronous Risk-Refinancing calls with the event-driven credit score our partner required to fund Pan-European refinancing.
  • Moved real-time fraud features from Data Science to Engineering.
  • Led EDA 2.0 across 12 repositories, simplifying setup so all engineers can use it, and set shared CI and code standards for Risk.
4SumUp, BerlinJun 2019 – Nov 2023

Senior Software Engineer

Built shared backend foundations: a service template, a money library used across backend and Android, and large data migrations.

  • Cut new service setup from a week to 1-2 hours with a service template.
  • Built the money library shared by SumUp's backend and Android apps, and the authorization and permissions libraries for point-of-sale services.
  • Migrated 6 years of historical data with minimal production impact.
4

SumUp, Berlin, GermanyJun 2019 – Nov 2023

Senior Software Engineer

Built shared backend foundations: a service template, a money library used across backend and Android, and large data migrations.

What I did

  • Cut new service setup from a week to 1-2 hours with a service template.
  • Built the money library shared by SumUp's backend and Android apps, and the authorization and permissions libraries for point-of-sale services.
  • Migrated 6 years of historical data with minimal production impact.
  • Added SLOs and on-call for critical point-of-sale services, showing how much risk we could take, how fast we responded, and what mattered.
3NICE, Ra'ananaDec 2017 – May 2019

Backend Software Developer

Backend development on a distributed product, focused on cache performance and reliability.

  • Refactored a product's cache system for performance and reliability.
  • Built Jira-integrated release tooling in Python.
2Inuitive, Ra'ananaAug 2014 – Dec 2017

C++/C# Developer

Vision-processing algorithms in C++, and production lines for the chips in South Korea and China.

  • Developed algorithms for vision processing chips in C++.
  • Set up production lines and their calibration tooling on-site in South Korea and China.
1Reichman University2012 – 2016

B.Sc. Computer Science

Courses, degrees, and topics that keep showing up in the work.

Courses and workshops:

  • Advanced Software Architecture Workshop with Residuality Theory · Workshop, 2024
  • Neo4j Fundamentals · Neo4j, 2024
  • Software Architecture & Design · Udemy, 2023
  • Design Patterns · Coursera, 2022
1

Reichman University2012 – 2016

B.Sc. Computer Science

Courses, degrees, and topics that keep showing up in the work.

Teaching

  • Teaching Assistant to Computer Science Professor in Intro to CS · Oct 2013 – Feb 2015
  • Teaching Assistant to Computer Science Professor in Advanced Programming · Mar 2014 – Aug 2014

Courses and workshops

  • Advanced Software Architecture Workshop with Residuality Theory · Workshop, 2024 · certificate
  • Neo4j Fundamentals · Neo4j, 2024 · certificate
  • Software Architecture & Design · Udemy, 2023 · certificate
  • Design Patterns · Coursera, 2022 · certificate
  • Kotlin for Java Developers · JetBrains, 2020 · certificate
LLobbyHow I work
Portrait of Yonatan Karp-Rudin

What people notice after working with me.

  • He sets the bar for what a Staff Engineer should be Mohamed Bouallegue, VP of Engineering at BillieLinkedIn recommendation, Oct 2026
  • I'd love to work with Yonatan again Blake Irvin, Leading Observability Engineering at SumUpLinkedIn recommendation, Sep 2025
  • the go-to person for almost any problem Oren Hadri, Former Engineering Manager at InuitiveLinkedIn recommendation, Oct 2018
  • a highly talented and disciplined software developer Shimon Schocken, Computer Science Professor, Reichman UniversityLinkedIn recommendation, Oct 2018
L

LobbyHow I work

I like the moment when a domain becomes specific enough to build.

In backend work the hard part is usually finding the real boundary: whose rule it is, which event is authoritative, what happens when a vendor disagrees, and how the next engineer will debug the failure at 2 a.m.

That is usually where I help. I keep asking until the domain is crisp enough to model, then turn it into production code, API contracts, migration plans, dashboards, runbooks, or diagrams that survive the handoff.

Good code is part of it. Most of the payoff comes later, when the whole team can run the system, extend it, and argue about it with evidence.

Works across
Backend systems, Kotlin/JVM, service design, OpenAPI, Kafka, internal tools, docs, and OSS
Bias toward
A shared vocabulary, small useful abstractions, boring reliability, and written explanations

Recommendations

Portrait of Mohamed Bouallegue

I’ve worked with many strong engineers, but very few like Yonatan.

What sets Yonatan apart is that he thinks like an engineer and a business owner at once. He brings strong technical judgment, but he’s driven just as much by understanding what the business actually needs. That combination made him a multiplier at Billie: he shipped high-quality systems, and he found opportunities that other teams went on to build on.

Yonatan was the person we turned to when priorities changed. When we moved him to a new domain, he took full ownership almost immediately and delivered as if he had been there from the start. That level of adaptability is rare, and it gave us real flexibility as an organization.

He is also always looking ahead. He was a driving force behind AI adoption at Billie, and his work fundamentally changed how we build software. He made it part of how we work instead of a side experiment.

He sets the bar for what a Staff Engineer should be. Any organization that gets to work with him is lucky, and I’d jump at the chance to work with him again.

Mohamed Bouallegue, VP of Engineering at BillieLinkedIn recommendation, Oct 2026
Portrait of Blake Irvin

I’d love to work with Yonatan again. He’s incredibly smart, cares deeply about quality but balances this with delivery speed, and (maybe most importantly) a great human to be teammates with.

Blake Irvin, Leading Observability Engineering at SumUpLinkedIn recommendation, Sep 2025
Portrait of Oren Hadri

I was privileged to have Yonatan on my team for almost 3 years. Yonatan is a dedicated, intelligent, and hard-working team player who played a key role in our team and was the go-to person for almost any problem. I have seen few people who could match his skills at solving technical problems, coding and design.

Oren Hadri, Former Engineering Manager at InuitiveLinkedIn recommendation, Oct 2018
Portrait of Shimon Schocken

Yonatan is a highly talented and disciplined software developer, with an excellent background in both computer science and programming. He is a people-person, with remarkable empathy and ability to recognize when and where students and developers need help and further guidelines. He is also a very pleasant and good-spirited colleague.

Shimon Schocken, Computer Science Professor, Reichman UniversityLinkedIn recommendation, Oct 2018

Skills

Backend architectureDesigning service boundaries and contracts that still make sense as a system grows.KotlinJavaSpring BootOpenAPIgRPCProtocol Buffers
Distributed systems and data flowsBuilding event-driven services and real-time processing, and keeping them running under load.KafkaNeo4jMySQLPostgreSQL
Platform and developer experienceImproving daily engineering work with templates, CI, internal tools, and shared libraries.GradleGitHub ActionsTerraformDockerKubernetes
Observability and operationsMaking production systems easier to monitor and debug.OpenTelemetryNew RelicKafka DLTs
Technical writingWriting about backend design, debugging, and implementation tradeoffs.KotlinMkDocs

Stack

Kotlin, Java, Spring Boot, OpenAPI, Kafka, Terraform, GitHub Actions, Docker, PostgreSQL, MySQL