Senior Backend Engineer (Go/PHP) – CIAM Migration (Auth0)

Senior Backend Engineer (Go/PHP) – CIAM Migration (Auth0)We are looking for a Senior Backend Engineer to join a high-impact Customer Identity and Access Management (CIAM) migration project. You will play a key role in transitioning the existing identity platform from AWS Cognito to Auth0, working across both legacy PHP systems and modern Golang microservices.This is a 100% remote role (CET timezone), offered as a fixed-term contract until September 2026.ResponsibilitiesImplement and support the migration from AWS Cognito to Auth0Develop and maintain backend services in Golang and PHPWork with both legacy monolith and modern microservices architectureAnalyze existing systems, integrations, and dependenciesParticipate in technical design and migration planningBreak down complex tasks and support delivery across teamsRequirements5+ years of experience in backend developmentStrong experience with Golang (Go) and PHPExperience working with legacy systems and monolith architectureSolid understanding of microservices architectureExperience with Auth0 or AWS CognitoGood knowledge of OAuth2, OpenID Connect, JWTExperience with REST APIs and system integrationsStrong analytical and problem-solving skillsNice to haveExperience with CIAM or identity systemsKnowledge of AWS and cloud-based architecturesExperience in system migrations or large-scale refactoringUnderstanding of authentication flows and user experience