Senior Backend Engineer (Node.js / NestJS) – Greenfield Product

<h1 data-section-id="8acsuy" data-start="281" data-end="348">Senior Backend Engineer (Node.js / NestJS) – Greenfield Product</h1> <p data-start="349" data-end="397"><strong data-start="349" data-end="397">Castle Tech GmbH – Berlin or Munich (Hybrid)</strong></p> <p data-start="399" data-end="567">We are building a <strong data-start="417" data-end="462">new standalone product from the ground up</strong> and are looking for a <strong data-start="485" data-end="512">Senior Backend Engineer</strong> to help design and build the system's foundation.</p> <p data-start="569" data-end="835">In this role, you will play a key&nbsp;<span style=" margin: 0px; padding: 0px;">role in&nbsp;<strong>shaping the product's architecture, backend services, and technical direction</strong></span>. You will work closely with frontend engineers, product managers, and stakeholders to turn ideas into reliable, scalable backend systems.</p> <p data-start="837" data-end="1016">This is an opportunity for engineers who enjoy <strong data-start="884" data-end="1015">designing systems, solving complex technical challenges, and taking ownership of meaningful projects from concept to production</strong>.</p> <hr data-start="1018" data-end="1021"> <h1 data-section-id="wbhumu" data-start="1023" data-end="1044">What You’ll Work On</h1> <ul data-start="1046" data-end="1645"> <li data-section-id="16lkqla" data-start="1046" data-end="1121"> <p data-start="1048" data-end="1121">Build and maintain <strong data-start="1067" data-end="1121">scalable backend services using Node.js and NestJS</strong></p> </li> <li data-section-id="n6hk0x" data-start="1122" data-end="1189"> <p data-start="1124" data-end="1189">Design a <strong data-start="1131" data-end="1160">clean system architecture</strong> for a new production product</p> </li> <li data-section-id="1p7svm2" data-start="1190" data-end="1254"> <p data-start="1192" data-end="1254">Take ownership of <strong data-start="1210" data-end="1254">features from concept through deployment</strong></p> </li> <li data-section-id="ox2s78" data-start="1255" data-end="1324"> <p data-start="1257" data-end="1324">Define and implement <strong data-start="1278" data-end="1324">APIs, services, and backend infrastructure</strong></p> </li> <li data-section-id="unecm2" data-start="1325" data-end="1399"> <p data-start="1327" data-end="1399">Collaborate with <strong data-start="1344" data-end="1399">frontend engineers, product managers, and designers</strong></p> </li> <li data-section-id="1qupuf9" data-start="1400" data-end="1486"> <p data-start="1402" data-end="1486">Establish <strong data-start="1412" data-end="1486">development standards, CI/CD pipelines, and engineering best practices</strong></p> </li> <li data-section-id="18cfa4n" data-start="1487" data-end="1559"> <p data-start="1489" data-end="1559">Mentor other engineers through <strong data-start="1520" data-end="1559">code reviews and technical feedback</strong></p> </li> <li data-section-id="bwcxma" data-start="1560" data-end="1645"> <p data-start="1562" data-end="1645">Continuously improve workflows using <strong data-start="1599" data-end="1645">modern tooling and AI-assisted engineering</strong></p> </li> </ul> <hr data-start="1647" data-end="1650"> <h1 data-section-id="4mbe8q" data-start="1652" data-end="1678">AI-Augmented Engineering</h1> <p data-start="1680" data-end="1706">AI is part of how we work.</p> <p data-start="1708" data-end="1852">We expect engineers to <strong data-start="1731" data-end="1804">actively use modern AI tools to improve development speed and quality</strong>, while maintaining strong engineering judgment.</p> <p data-start="1854" data-end="1880">You should be comfortable:</p> <ul data-start="1882" data-end="2121"> <li data-section-id="pp707u" data-start="1882" data-end="1943"> <p data-start="1884" data-end="1943">Using <strong data-start="1890" data-end="1918">AI-assisted coding tools</strong> in your daily workflow</p> </li> <li data-section-id="1t82lkm" data-start="1944" data-end="2013"> <p data-start="1946" data-end="2013">Writing effective prompts and <strong data-start="1976" data-end="2011">critically evaluating AI output</strong></p> </li> <li data-section-id="71zpg" data-start="2014" data-end="2066"> <p data-start="2016" data-end="2066">Identifying <strong data-start="2028" data-end="2064">AI limitations and failure modes</strong></p> </li> <li data-section-id="1m9w6db" data-start="2067" data-end="2121"> <p data-start="2069" data-end="2121">Exploring modern <strong data-start="2086" data-end="2121">AI-driven development workflows</strong></p> </li> </ul> <p data-start="2123" data-end="2238">This role is for engineers who see AI as a <strong data-start="2166" data-end="2197">tool to enhance engineering</strong>, not replace good engineering practices.</p> <hr data-start="2240" data-end="2243"> <h1 data-section-id="1r7bi2d" data-start="2245" data-end="2258">Your Skills</h1> <h3 data-section-id="19d0r9f" data-start="2260" data-end="2273">Must Have</h3> <ul data-start="2275" data-end="2810"> <li data-section-id="lrryow" data-start="2275" data-end="2323"> <p data-start="2277" data-end="2323"><strong data-start="2277" data-end="2323">5+ years of backend engineering experience</strong></p> </li> <li data-section-id="1b83989" data-start="2324" data-end="2384"> <p data-start="2326" data-end="2384">Strong experience with <strong data-start="2349" data-end="2384">TypeScript, Node.js, and NestJS</strong></p> </li> <li data-section-id="1nx72kx" data-start="2385" data-end="2442"> <p data-start="2387" data-end="2442">Experience designing <strong data-start="2408" data-end="2442">scalable backend architectures</strong></p> </li> <li data-section-id="vrj9sw" data-start="2443" data-end="2524"> <p data-start="2445" data-end="2524">Strong understanding of <strong data-start="2469" data-end="2524">software design principles and maintainable systems</strong></p> </li> <li data-section-id="1jqxcya" data-start="2525" data-end="2591"> <p data-start="2527" data-end="2591">Experience with <strong data-start="2543" data-end="2591">relational databases (PostgreSQL or similar)</strong></p> </li> <li data-section-id="sscscj" data-start="2592" data-end="2654"> <p data-start="2594" data-end="2654">Experience working with <strong data-start="2618" data-end="2654">Git, CI/CD pipelines, and Docker</strong></p> </li> <li data-section-id="1tmfg11" data-start="2655" data-end="2707"> <p data-start="2657" data-end="2707">Experience mentoring or supporting other engineers</p> </li> <li data-section-id="1c6abb" data-start="2708" data-end="2765"> <p data-start="2710" data-end="2765">Experience working in <strong data-start="2732" data-end="2765">agile teams (Scrum or Kanban)</strong></p> </li> <li data-section-id="1t422a4" data-start="2766" data-end="2810"> <p data-start="2768" data-end="2810">Strong communication skills in <strong data-start="2799" data-end="2810">English</strong></p> </li> </ul> <hr data-start="2812" data-end="2815"> <h3 data-section-id="gxq2rq" data-start="2817" data-end="2833">Nice to Have</h3> <ul data-start="2835" data-end="3129"> <li data-section-id="dn2k2g" data-start="2835" data-end="2900"> <p data-start="2837" data-end="2900">Experience with <strong data-start="2853" data-end="2900">microservices or event-driven architectures</strong></p> </li> <li data-section-id="z7v855" data-start="2901" data-end="2960"> <p data-start="2903" data-end="2960">Experience building <strong data-start="2923" data-end="2960">greenfield or standalone products</strong></p> </li> <li data-section-id="ddqbx0" data-start="2961" data-end="3037"> <p data-start="2963" data-end="3037">Familiarity with <strong data-start="2980" data-end="3005">AI-related components</strong> such as RAG or vector databases</p> </li> <li data-section-id="1jp9uxe" data-start="3038" data-end="3101"> <p data-start="3040" data-end="3101">Experience integrating <strong data-start="3063" data-end="3101">AI services or data-driven systems</strong></p> </li> <li data-section-id="1msgjy2" data-start="3102" data-end="3129"> <p data-start="3104" data-end="3129"><strong data-start="3104" data-end="3129">Conversational German</strong></p> </li> </ul> <hr data-start="3131" data-end="3134"> <h1 data-section-id="3y8qow" data-start="3136" data-end="3153">What You’ll Own</h1> <p data-start="3155" data-end="3265">As a <strong data-start="3160" data-end="3179">Senior Engineer</strong>, you will play a key role in shaping both the <strong data-start="3226" data-end="3264">technology and engineering culture</strong>.</p> <p data-start="3267" data-end="3276">You will:</p> <ul data-start="3278" data-end="3706"> <li data-section-id="15jy571" data-start="3278" data-end="3360"> <p data-start="3280" data-end="3360">Design backend systems with <strong data-start="3308" data-end="3360">clear service boundaries and scalability in mind</strong></p> </li> <li data-section-id="12in0mc" data-start="3361" data-end="3429"> <p data-start="3363" data-end="3429">Identify <strong data-start="3372" data-end="3429">technical risks early and propose effective solutions</strong></p> </li> <li data-section-id="uxhoua" data-start="3430" data-end="3492"> <p data-start="3432" data-end="3492">Contribute to <strong data-start="3446" data-end="3492">architecture discussions and system design</strong></p> </li> <li data-section-id="nsjqu" data-start="3493" data-end="3556"> <p data-start="3495" data-end="3556">Improve the <strong data-start="3507" data-end="3556">team’s engineering standards and productivity</strong></p> </li> <li data-section-id="1mslcsy" data-start="3557" data-end="3623"> <p data-start="3559" data-end="3623">Mentor engineers and contribute to <strong data-start="3594" data-end="3623">technical decision-making</strong></p> </li> <li data-section-id="16wqaj5" data-start="3624" data-end="3706"> <p data-start="3626" data-end="3706">Deliver high-impact backend features aligned with <strong data-start="3676" data-end="3706">product and business goals</strong></p> </li> </ul> <hr data-start="3708" data-end="3711"> <h1 data-section-id="1r99sjv" data-start="3713" data-end="3736">Why Join Castle Tech?</h1> <ul data-start="3738" data-end="4294"> <li data-section-id="1g8c6q4" data-start="3738" data-end="3813"> <p data-start="3740" data-end="3813"><strong data-start="3740" data-end="3763">Build something new</strong> – work on a greenfield product from the beginning</p> </li> <li data-section-id="13arnkd" data-start="3814" data-end="3887"> <p data-start="3816" data-end="3887"><strong data-start="3816" data-end="3844">Real technical ownership</strong> – influence system design and architecture</p> </li> <li data-section-id="5437hi" data-start="3888" data-end="3962"> <p data-start="3890" data-end="3962"><strong data-start="3890" data-end="3924">Modern engineering environment</strong> – Node.js, NestJS, and modern tooling</p> </li> <li data-section-id="42bx1f" data-start="3963" data-end="3999"> <p data-start="3965" data-end="3999"><strong data-start="3965" data-end="3999">AI-forward engineering culture</strong></p> </li> <li data-section-id="12mwtli" data-start="4000" data-end="4071"> <p data-start="4002" data-end="4071"><strong data-start="4002" data-end="4023">Hybrid work model</strong> – office and remote options in Berlin or Munich</p> </li> <li data-section-id="1rhhh70" data-start="4072" data-end="4147"> <p data-start="4074" data-end="4147"><strong data-start="4074" data-end="4100">Your gear, your choice</strong> – MacBook or Windows with the tools you prefer</p> </li> <li data-section-id="1ceh105" data-start="4148" data-end="4213"> <p data-start="4150" data-end="4213"><strong data-start="4150" data-end="4176">Growth and development</strong> – structured onboarding and coaching</p> </li> <li data-section-id="8akwr2" data-start="4214" data-end="4294"> <p data-start="4216" data-end="4294"><strong data-start="4216" data-end="4238">Collaborative team</strong> – ambitious engineers who enjoy building great products</p> </li> </ul> <hr data-start="4296" data-end="4299"> <p data-start="4301" data-end="4462">&nbsp;</p>