>cat jonas-petrik-cv.md

# Summary

~/jonas-petrik-cv.md

Jonas Petrik

Staff Engineer / Team Lead · Backend & platform for high-traffic e-commerce checkout

Bavaria, Germany · Remote, EU

Summary

Staff Engineer and Team Lead with 14+ years in backend and platform engineering (PHP, Go, Kubernetes, AWS). I lead a 7-person checkout team at SCAYLE, the commerce platform behind 200+ enterprise online shops such as Harrods, Deichmann and Levi's. I work on performance, high availability and software architecture for payment-critical systems. Checkout held 1,000 checkouts per minute in a production load test and peaked at about 550 orders per minute on Black Friday 2025, with zero checkout downtime during the high-load period.

jonas@petrik.devhttps://petrik.devLinkedInGitLabGitHub
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Experience

SCAYLE

promoted internally

Senior Software Engineer (Checkout) → Staff Engineer / Team Lead (Checkout)

Jan 2024 – Present

Hamburg, Germany - Remote

Staff Engineer / Team Lead (Checkout)

Apr 2025 – Present

Lead the checkout team and stay hands-on with backend, platform and architecture for a multi-brand commerce platform.

highlights

  • -Lead a 7-person checkout team: 4 senior developers, 1 QA and 1 product owner. Run releases, on-call quality, the security backlog and onboarding.
  • -Replaced resource-based autoscaling for checkout with traffic-based autoscaling (requests in flight, with KEDA) and capped work per pod. Live in production ahead of Black Friday 2026. In a production load test, it handled 1,000 checkouts per minute for 10 minutes. 99.97% completed, none were dropped, and the service scaled out about 10× on its own.
  • -Led checkout through Black Friday 2025, with a peak of about 550 orders per minute and zero checkout downtime during the high-load period.
  • -Raised the largest basket from 75 to 500 unique configured items in load tests. Ran 15+ measured load-test rounds with Blackfire and Datadog. Each round found the next bottleneck. One round alone cut a 500-item checkout time by 44%.
  • -Designed the plan to separate checkout from the legacy order system, so that its outages and slowness will not stop customers from paying.
  • -Designed and built the A/B testing backend and conditional delivery fees. Both are live. Wrote 30+ design documents and technical proposals in total, covering shipping, payments, promotions and API contracts.
  • -Owned checkout reliability. Rewrote the monitoring-duty process, checked every SLO against what Datadog really measured, and wrote 15+ incident reports with fixes. Cut response times by 100–270 ms per checkout step.
  • -Use AI coding agents daily, with review rules for their output. Wrote an internal guide on where AI gets things wrong.

Senior Software Engineer (Checkout)

Jan 2024 – Apr 2025

Hands-on backend engineer on high-throughput, headless checkout for multi-tenant commerce.

highlights

  • -One of the key engineers who built the new checkout API on Laravel and RoadRunner. In 2024 it replaced the old checkout for every brand on the platform. Led many of its design decisions.
  • -Ran the Black Friday 2024 load test. Checkout passed well above its goal.
  • -Built payment and delivery features: payment provider integrations, express checkout, loyalty points, addresses and pickup points.
  • -Took on checkout on-call. This led to observability and error-reduction work that was part of the reason for my promotion.

PHP · Go · Kubernetes · KEDA · Laravel · Laravel Octane · RoadRunner · Symfony · Doctrine · FrankenPHP · gRPC · TypeScript · React · Redux · Redis · MySQL · Kubernetes HPA · Helm · Docker · AWS · SQS · SNS · Terraform · Datadog · Datadog APM · Blackfire · k6 · GitLab CI · OpenAPI · oasdiff · Trivy · PHPUnit · Jest · Cypress · Playwright · Claude Code

anwalt.de

promoted internally

Senior Software Developer → Senior Software Engineer Team Lead

Dec 2020 – Dec 2023

Nuremberg, Germany - Remote

Senior Software Engineer Team Lead

Dec 2022 – Dec 2023

Led a small platform team and stayed hands-on with backend, DevOps and architecture for Germany's largest legal marketplace.

highlights

  • -Led a 3-person team that built delivery and platform foundations. Other teams adopted them.
  • -Led modernization of database migrations, AWS infrastructure and deployable code patterns in a legacy codebase.
  • -Improved CI/CD and deployment safety with the DevOps team.
  • -Mentored engineers through code review and shared engineering practices.

Senior Software Developer

Dec 2020 – Dec 2022

Senior backend and full-stack engineer on search and marketplace features.

highlights

  • -Rebuilt anwalt.de search on Elasticsearch with GraphQL, geolocation, aggregations and range filters, for a marketplace with 4M+ monthly users.
  • -Migrated legacy code into services that are easier to maintain.
  • -Earned promotion to the lead role after the search rebuild.

PHP · Laminas · Go · Vue.js · TypeScript · MySQL · Elasticsearch · AWS · Docker · Kubernetes · REST · New Relic · GraphQL · Bitbucket Pipelines · SQS · Logstash · Kibana · Terraform · PHPUnit · Jest · EC2 · S3 · RDS · Lambda · Bugsnag · Algolia

SOLUTIONLAB PRODUCTION

promoted internally

Senior Web Developer → Senior Software Engineer Team Lead

Nov 2017 – Dec 2020

Senior Software Engineer Team Lead

Jan 2018 – Dec 2020

Vilnius, Lithuania - Hybrid

Team lead and hands-on engineer for Atobi and other retail products, at a dev house for startup and enterprise clients.

highlights

  • -Led the migration of Atobi from a prototype stack to a Laravel API, a React frontend and mobile apps.
  • -Designed a reusable gamification system for engagement and calls to action. Multiple products used it.
  • -Scaled the team from 3 to 10 engineers. Turned client product ideas into technical plans.
  • -Built offline-first and real-time retail app features for enterprise clients.

Senior Web Developer

Nov 2017 – Jan 2018

Vilnius, Lithuania - Remote

Senior backend engineer on a retail startup account at a dev house.

highlights

  • -Joined to build backend services for a retail startup and moved into the lead role within two months.

PHP · Laravel · Phalcon · React · React Native · JavaScript · MySQL · Redis · AWS · Docker · REST · Agile · SCRUM · Redux · SQLite · OneSignal · Jenkins · Laravel Nova · Laravel Queues · Sentry · Terraform · jQuery

Olympic Casino Group Baltija

Jan 2017 – Nov 2017

Vilnius, Lithuania - On-site

Full Stack Engineer

Jan 2017 – Nov 2017

Full-stack engineer on betting systems with a focus on correctness, latency and transaction handling.

highlights

  • -Built features for real-time betting products with strict rules for financial correctness.
  • -Worked under a stricter TDD culture than most web teams. This improved how I handle safety and regression risk.

PHP · Laravel · Vue.js · JavaScript · MySQL · Redis · Docker · REST · TDD · PHPUnit · Kubernetes · Jenkins · Bitbucket

Earlier experience

  • UAB inlusion Netforms, Senior Software Engineer → Team Lead (Nov 2015 – Jan 2017): led a distributed team of 10 on ERP and CRM projects (C#/.NET, PHP, Laravel, Vue.js).
  • UAB Integrus, Full Stack Engineer (Nov 2014 – Nov 2015): warehouse workflows and DPD/DHL/UPS shipping integrations for automotive e-commerce (PHP, Laravel).
  • Itlogas JSC, Ruby on Rails Developer (Feb 2014 – Oct 2014): voter-registration and campaign platform.
  • Profectus Novus, PHP Web Developer (Apr 2013 – Feb 2014): government education platform on SharePoint.

Skills

Backend and Platform Engineering:
PHP, Go, Laravel, Laravel Octane, RoadRunner, Symfony, Doctrine, FrankenPHP, gRPC, Redis, MySQL, OpenAPI, Elasticsearch, REST, GraphQL
Infrastructure and Reliability:
Kubernetes, KEDA, Kubernetes HPA, Helm, Docker, AWS, SQS, SNS, Terraform, Datadog, Datadog APM, Blackfire, k6, GitLab CI, Trivy
Frontend and Delivery:
TypeScript, React, oasdiff, Jest, Cypress, Playwright, Vue.js
AI tools:
Claude Code

Education

Vilniaus Universitetas, Bachelor's degree in Software Engineering (2011 – 2015)

Languages

Lithuanian (native), English (fluent), Russian (fluent), German (basic speaking proficiency; good comprehension)