Serhii Halchenko
Engineering Manager - Login Platform
Stockholm, Sweden
Summary
👤
Senior🎓
Top SchoolSerhii Halchenko is an engineering manager based in Stockholm with 12 years of experience building authentication and login platforms, currently leading Klarna's global OpenID Connect solution. He combines hands-on full-stack expertise (JS/TypeScript, React, Node.js) and cross-platform C++ experience with proven SRE and cloud infrastructure skills (AWS, EKS, Terraform, GitOps). At Klarna he scaled customer login and app authentication for millions of users and hired and grew teams to deliver an OpenID-compliant platform integrated across customer flows. Serhii is also an active open-source contributor to the widely used ory/hydra project, adding session management, refresh-token improvements, and back-channel logout support to strengthen OAuth2/OpenID workflows. Comfortable switching between product-facing frontends and security-critical backends, he favors pragmatic, auditable engineering practices like CI/CD, infrastructure-as-code, and robust testing. His background in technical cybernetics and AI gives him a systems-oriented perspective that surfaces non-obvious tradeoffs in authentication and session design.
12 years of coding experience
13 years of employment as a software developer
Engineer's degree, Technical Cybernetics, AI, Software Development, Engineer's degree, Technical Cybernetics, AI, Software Development at Dnipropetrovsk State Technical University of Railway Transport
English, Russian, Ukrainian
Github Skills (13)
authorizations10
go10
api10
back-end-development10
apidoc10
session-management10
oauth10
authorization10
openid-connect10
security9
dockers5
cloud-computing5
docker5
Programming languages (7)
Github contributions (5)
ory/hydra
Aug 2022 - Aug 2022
Internet-scale OpenID Certified™ OpenID Connect and OAuth2.1 provider that integrates with your user management through headless APIs. Solve OIDC/OAuth2 user cases over night. Consume as a service on Ory Network or self-host. Trusted by OpenAI and many others for scale and security. Written in Go.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:35 reviews, 1 commit, 6 PRs in 1 day
Contributions summary:Serhii contributed significantly to the `ory/hydra` project, focusing on backend features related to OpenID Connect and OAuth2. Their work included adding session management capabilities, specifically integrating session IDs into refresh token webhooks. They also implemented the ability to revoke login sessions via SessionID, including back-channel logout functionalities. Furthermore, the user enhanced the session management, allowing session lifespans to be extended when accepting login challenges and added an index to the `requested_at` field in refresh tokens.
gooauthopenaiopenidopenid-connect
sgal/utvecklarbolaget
Jun 2014 - Nov 2017
Contributions:46 commits, 2 PRs, 35 pushes in 3 years 6 months
cssresponsiveresponsive-website
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