Senior Backend Engineer II, Authentication & Authorization

About the company

Vinted is a second-hand marketplace that connects buyers and sellers and operates integrated logistics and payments services.

About this role

<div class="content-intro"><h2><strong>Brief info about Vinted&nbsp;</strong></h2> <p data-renderer-start-pos="1"><span data-sheets-root="1">Our mission is to make second-hand the first choice, and we're looking for people who want to help us get there. Every day, we work together to help our members buy and sell pre-loved clothing and lifestyle items, giving each piece a second life – or even a third. <br>The Vinted Group is made up of three business units that support this mission:<br><br><strong><a href="https://careers.vinted.com/marketplace" target="_blank">Vinted Marketplace</a></strong> is Europe’s leading platform for second-hand fashion and a go-to destination for all kinds of pre-loved items, with a growing range of categories. Our platform connects millions of members across 20+ markets, helping great items find a new life.<br><br><a href="https://careers.vinted.com/vintedgo" target="_blank"><strong>Vinted Go</strong></a> enhances the shipping experience with a vast network of over 500,000 pick-up and drop-off points, partnering with more than 60 carriers across Europe, with added services like item verification for peace of mind on high-value pieces.<br><br><a href="https://careers.vinted.com/vintedpay" target="_blank"><strong>Vinted Pay</strong></a> is the newest part of the Vinted Group, dedicated to bringing secure, reliable payments to buyers and sellers across Europe. Seamlessly integrated into the Vinted app, it helps keep every transaction safe, efficient, and easy for our members.<br><br>Founded in 2008 in Lithuania, Vinted began as a way for friends to find new homes for clothes they no longer needed. In 2019, we became Lithuania's first unicorn! Today, our headquarters remain in Vilnius, and we've grown with offices across Europe, supported by a team of over 2,000 people.&nbsp;</span></p></div><h2><strong>Information about the position&nbsp;</strong></h2> <p>Authentication and authorization underpin nearly every interaction on Vinted. They determine how members, employees, and services prove who they are, and what they are allowed to do.</p> <p>Today, these responsibilities span our core platform, dedicated identity services, gateways, service-mesh infrastructure, and workforce systems. We are evolving this landscape towards a shared identity model and an authorization platform that is secure, reliable, observable, and straightforward for engineering teams to adopt.</p> <p>We’re looking for a Senior Backend Engineer II to join the Authentication and Authorization team. You’ll work across two connected areas:</p> <ul> <li>Evolving authentication towards a consistent, federated identity model for members, employees, and systems</li> <li>Building shared authorization capabilities that replace fragmented, service-specific solutions with common concepts, APIs, tooling, and decision observability</li> </ul> <p>This is neither a purely greenfield role nor a legacy-maintenance role. You’ll help extract existing functionality safely, improve production services, and build new platform capabilities.</p> <p>We’re looking for an experienced engineer, but not necessarily someone who already knows every part of identity and access management. What matters is strong engineering judgement, curiosity, and the ability to learn unfamiliar technologies and domains. You should be comfortable going deep into a technical problem, then zooming out to understand how the solution affects users, services, infrastructure, security, and other engineering teams.</p> <h2><strong>In this position, you’ll&nbsp;</strong></h2> <ul> <li>Design, build, and operate backend services supporting authentication, identity propagation, token exchange, authorization decisions, and policy management</li> <li>Help extract authentication functionality from existing systems while preserving feature parity, controlling rollout risk, and retiring legacy paths safely</li> <li>Contribute to stable identity and authorization contracts that allow services to evolve without depending on individual identity providers, token formats, or API implementations</li> <li>Build shared authorization capabilities, including a capability registry, policy APIs, decision logs, and tools for understanding who or what can access a resource</li> <li>Improve supported integration paths - such as SDKs, libraries, conformance tests, documentation, and migration tooling - that make secure adoption easier for other teams</li> <li>Work with Registration, Platform, Security, and product-domain engineers to define ownership boundaries, integration contracts, and safe migration plans</li> <li>Keep security-critical systems reliable and observable by contributing to SLOs, latency expectations, failure behaviour, monitoring, and operational response</li> <li>Take ownership of complex areas of work from design through implementation, rollout, and production operation</li> <li>Contribute to technical proposals and architectural decisions, helping the team understand the available trade-offs</li> <li>Support other engineers through thoughtful code reviews, pairing, documentation, and knowledge sharing</li> <li>Write, review, test, deploy, monitor, and troubleshoot production code</li> </ul> <h2><strong>About you&nbsp;</strong></h2> <p>You’re an experienced backend engineer who can take responsibility for difficult or unfamiliar problems. You don’t need to arrive with every answer. You’re comfortable saying, “I don’t know yet,” then learning enough to make a thoughtful decision and move the work forward.You can work across a wide technical surface without losing sight of the underlying problem. You know when to investigate deeply, when to involve someone else, and when a pragmatic solution is better than an elaborate one.</p> <p>We’d expect that:</p> <ul> <li>You have a strong track record of building and operating distributed backend systems in production</li> <li>You can take ownership of complex backend work, including design, delivery, rollout, and