Summary: Join a specialized engineering team at Zaleos to develop and maintain backend software and RTC services, focusing on secure, stable, and always-available communications. Highlights: 1. Work on mission-critical real-time communication systems 2. Culture of engineering excellence, quality, and technical responsibility 3. Directly contribute to reliability of critical infrastructures #### **About us** At **Zaleos**, we build software for **real\-time communication (RTC) systems**. We design, develop, test, and maintain software for companies that rely on protocols such as **SIP, RTP, and WebRTC**. Our mission is clear: **to help organizations ensure secure, stable, and always\-available communications.** We work in **mission\-critical environments** where reliability is not optional: * **Voice AI**: we enhance the telephony layer for conversational agents and intelligent voice platforms. * **Enterprise Communications**: we develop software for **VoIP, CPaaS, and cloud PBX platforms**. * **Emergency Systems**: extensive experience designing and building **Core Services for emergency call networks in the U.S.** Since **2015**, we have been helping companies across different industries keep their RTC communications running at all times, with a culture focused on **engineering excellence, quality, and technical responsibility**. #### **Our Culture \& Values** At Zaleos, we share a culture built on **trust, autonomy, and technical excellence**. Every team member acts with responsibility and professional judgment, contributing solutions while safeguarding product quality. **Our values:** * **Total Integrity** Transparency, accountability, and trust — even when things don’t go as planned. * **Ownership** Everyone works with autonomy and a strong sense of ownership over their work. * **Excellence** We deliver clean, stable, and maintainable systems we can truly be proud of. #### **How We Build Software** At Zaleos, we take engineering seriously. Our culture blends **Agile, Lean, and DevOps principles**, with a strong focus on **technical resilience, architectural clarity, and continuous improvement**. Our technical principles — **The Tao of Zaleos** — guide everything we do: * **Resiliency – Always up, always ready.** We design for fault tolerance and continuous availability. * **Strategic Modularity – Low coupling, high cohesion.** We build clear, cohesive modules with minimal dependencies. * **Immutability – Certainty through consistency.** Everything we deploy is automated and controlled — no improvisation. * **Everything as Code – What is not version\-tracked is lost.** All critical assets are under version control. * **Pragmatism – Effective solutions over perfect ideals.** We prioritize useful solutions over theoretically perfect ones. #### **Who We're Looking for** We’re looking for someone with a **solid technical foundation** and a strong desire to keep growing, who enjoys working on **real\-time communication systems** and **real\-world products**, often in direct contact with clients. You’ll be part of a **specialized engineering team**, where technical quality, continuous learning, and collaboration are key. Your work will directly contribute to the **reliability of critical infrastructures** and the **technological evolution of our clients**, supported by senior engineers in an environment designed for growth. #### **What you'll do** Your responsibilities will include: * Developing and maintaining **backend software components and RTC services**. * Working with Open Source technologies and products such as **Kamailio, FreeSWITCH, and OpenSIPS**, including their configuration and operation. * Implementing features and technical improvements following team\-defined architectures and standards. * Performing **functional, load, and interoperability testing** to ensure system quality and stability. * Automating tasks and contributing to technical quality through **CI/CD, testing, and documentation**. * Participating in **technical support and consulting tasks**, learning how to analyze infrastructure, reliability, and performance issues. * Supporting the growth of junior engineers by sharing knowledge, reviewing simple code, and collaborating on onboarding. * Collaborating with **international technical and product teams**, using English on a daily basis. #### **Requirements** * At least **3 years of experience as a Software Engineer** (or equivalent level), with real autonomy in production environments. * Strong command of at least one **backend programming language** (Java, Go, Python, or similar). * Experience with **automated testing** and **CI/CD pipelines**. * Interest in **distributed systems**, real\-time communications, and demanding technical environments. * Ability to work as part of a team, communicate clearly, and ask for help when needed. * Good level of **technical English** and fluency in international environments. * Continuous learning mindset and willingness to gradually take on **greater technical responsibility**. * Analytical, responsible mindset focused on **continuous improvement**. #### **What You'll Get** * **Hybrid work model** (Pozuelo de Alarcón – UPM Montegancedo Campus). **On\-site** Tuesday, Wednesday, and Thursday. **Remote** on Monday and Friday. * **Flexible working hours**, allowing a start time between **7:30 AM and 9:30 AM**. * **Reduced working** hours during the **summer months.** * **Semi\-annual performance and professional development reviews**. * **24 days of vacation**, including your birthday. * A **collaborative, close\-knit, and highly skilled technical tea.** * Talent referral **bonus program.** #### **Why Zaleos?** Because here, **engineering has a purpose**. Every project impacts our clients’ real\-time communications and helps keep **critical communication systems running worldwide**. If you’re passionate about technology, motivated by technical challenges, and value **quality over quantity**, **this is the place for you**.